Browsing by Author "Anupam Patel"

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A novel hybrid sodium ion capacitor based on Na [Ni0.60Mn0.35Co0.05] O2 battery type cathode and presodiated D-Ti3C2Tx pseudocapacitive anode
(Elsevier Ltd, 2024) Vikas Yadav; Anupam Patel; Anurag Tiwari; Samriddhi; Shitanshu Pratap Singh; Raghvendra Mishra; Rajendra K. Singh
The combination of the high-power density of supercapacitors and the high energy density of batteries makes hybrid sodium-ion capacitors (HSICs) a promising device. HSICs can provide better performance characteristics by harnessing both ion adsorption/desorption in the capacitor-type electrode and sodium-ion intercalation in the battery-type electrode. Here, the synthesis of MXene (Ti3C2Tx), a two-dimensional (2D) carbide and nitride is reported. Delaminated MXene (D-Ti3C2Tx) is a promising candidate for anode material in HSIC due to its large surface area (∼ 42 m2/g) and good electronic conductivity. Electrochemical study indicates that D-Ti3C2Tx anode exhibits a high discharge capacity of ∼213 mAh/g at a current rate of 20 mA/g. Further the presodiated D-Ti3C2Tx anode is paired with Na [Ni0.60Mn0.35Co0.05] O2 (P2-NMC) cathode to obtain the configuration of HSIC. The HSIC exhibits good specific capacitance of ∼187 F/g and specific discharge capacity of ∼110 mAh/g at a current density of 10 mA/g, according to the electrochemical analysis. A notable improvement in specific energy density (∼ 256 Wh/kg) and specific power density (∼579 W/kg) is also demonstrated by the HSIC. With P2-NMC being used as the cathode material rather than traditional activated carbon, there has been a rise in specific energy density. © 2024 Elsevier B.V.
A twofold approach for prolonging the lifespan of cobalt-free Na[Ni0.55Mn0.35Fe0.1]O2 cathode via Bi5+-doping and Bi2O3 coating in sodium ion batteries
(Elsevier Ltd, 2024) Raghvendra Mishra; Rupesh K. Tiwari; Anupam Patel; Anurag Tiwari; Rajendra K. Singh
A cobalt-free biphasic (P2/O3) layered Na[Ni0.55Mn0.35Fe0.1]O2 (NFM) cathode material has been synthesized and dual surface and structural modifications have been performed. Bi5+ is doped into pure NFM in order to tune the P2/O3 phase, whereas, a thin layer of Bi2O3 is coated on surface of the Bi5+-doped NFM (BNFM) for surface modification. The structure, morphology, and electrochemical performance of prepared samples are analyzed and compared by various characterization techniques. The pristine NFM cathode exhibits the specific discharge capacity of 170 mAh g−1, while Bi-doped cathode exhibits 181 mAh g−1, and Bi2O3 coated cathode renders 180 mAh g−1. It is observed that, pristine NFM cathode suffers rapid capacity degradation and nearly ~80 % capacity loss within first 250 cycles. After 1000 cycles, BNFM shows 47 % capacity retention, while, Bi2O3 coated BNFM (BNMF@Bi2O3) shows 73 % capacity retention of initial capacity. This improvement in the rate capability is obtained due to the effect of Bi-doping and Bi2O3 coating, where, former enlarges interlayer spacing and latter provides the ionic conducting channel as well as protects the particle from the contact of the electrolyte. The combined effect of Bi-doping and Bi2O3 coating facilitates fast diffusion of Na-ions within the transition metal layers resulting in superior rate capability. © 2023 Elsevier Ltd
Boosting sodium hybrid-ion capacitor performance via exfoliated Ti3C2TX (O/OH/F) anode and bio-derived activated hard carbon cathode
(Elsevier Ltd, 2025) Vikas G. Yadav; Anupam Patel; Anurag Tiwari; Samriddhi; Shitanshu Pratap Singh; Tanya Jaiswal; Rajendra K. Singh
The exfoliated MXene (eTCT) was synthesized from its parent MAX phase using a hydrofluoric acid-free etching system (HCl/LiF). The resulting eTCT sample exhibits a specific surface area of 51 m2 g−1 The fabricated eTCT electrode demonstrates remarkable electrochemical performance, delivering a high gravimetric specific discharge capacity of ∼280 mAh g−1 and an impressive specific capacitance of ∼385 F g−1, along with excellent rate capability. Cyclic voltammetry measurements reveal maximum specific capacitances of ∼730 F g−1 and ∼ 418 F g−1 at scan rates of 0.1 mV/s and 0.5 mV/s, respectively. After 150 cycles, the eTCT cell retains approximately 70 % of its initial discharge capacity, corresponding to a capacity fade rate of only 0.2 % per cycle. For energy storage applications. Further MXene's potential is explored by fabricating a sodium hybrid-ion capacitor (SHIC). Based on the total active mass of both electrodes, the SHIC achieves a gravimetric specific capacitance of 79 Fg−1. The eTCT//AMHC system demonstrates outstanding power and energy densities reaching ∼4.1 kW k g−1 and 156 Wh k g−1, respectively. These values surpass many lithium-based capacitors, highlighting the superior performance of MXene-based devices. The Wien2k calculations reveal that LiF-etched MXene exhibits enhanced electronic conductivity. Notably, MXene ([sbnd]F, -OH, [sbnd]O) show higher density of states (DOS) near the Fermi level compared to MAX phase, suggesting the enhancement in metallic character of MXene. Furthermore, the strong Na[sbnd]O interaction in Ti3C2O2 makes it particularly promising for sodium-ion storage applications. © 2025
Conducting Carbon Rich Graphitic Carbon Nitride Nanosheets with Attached Nano Sulfur Copolymer as High Capacity Cathode for Long-Lifespan Lithium-Sulfur Battery
(John Wiley and Sons Inc, 2022) Rupesh K. Tiwari; Shishir K. Singh; Nitin Srivastava; Raghvendra Mishra; Dipika Meghnani; Anupam Patel; Anurag Tiwari; Vimal K. Tiwari; Rajendra K. Singh
A mesoporous, conducting, high specific surface area, carbon-rich graphitic carbon nitride (GCN) nanosheets host covered by nano sulfur copolymer has been reported as a cathode material that shows high capacity along with long cyclability for rechargeable lithium-sulfur batteries (LiSBs). The thermal pyrolysis technique has been used for carbon-rich GCN sheets synthesis, and the chemical deposition approach has been used to attach surface nanoparticles to the sheets. Further, to improve the binding of nano sulfur with host material, copolymerization of nano sulfur is carried out with help of 1,3-diethynylbenzene (DEB) monomer through the solution route. The sulfur nanoparticles are loaded on conducting carbon-rich GCN framework for fast electro kinematics and further copolymerization of sulfur nanoparticles is done to prevent the dissolution of the active material (sulfur) into the electrolyte during the charging/discharging for high capacity and long cycle life rechargeable LiSBs cathode preparation. The synthesized composite with high sulfur loading (∼76 wt.% of composite cathode material) as cathode shows an initial discharge capacity of ∼1380 mAh g−1 at 0.1 C and a good discharge capacity of ∼700 mAh g−1 after 1000 cycles at 1 C with ultra-low-capacity fading ∼0.016 % of the initial capacity in each cycle. © 2022 Wiley-VCH GmbH.
Diffusion mechanism in a sodium superionic sulfide-based solid electrolyte: Na11Sn2AsS12
(Institute of Physics, 2022) Anurag Tiwari; Shishir K. Singh; Nitin Srivastava; Dipika Meghnani; Raghvendra Mishra; Rupesh K. Tiwari; Anupam Patel; Himani Gupta; Vimal K. Tiwari; Rajendra K. Singh
Recently, in all solid-state batteries, sulfide-based solid electrolytes have received increased attention due to their high ionic conductivity, good mechanical features, and better chemical stability. Therefore, in the present study, we have synthesized a novel sodium superionic conducting sulfide-based inorganic solid electrolyte (Na11Sn2AsS12) using a solid-state reaction method. The prepared solid electrolyte (Na11Sn2AsS12) is characterized by different techniques such as x-ray diffractometry (XRD), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy, thermogravimetric analysis (TGA), electrochemical impedance spectroscopy, and linear sweep voltammetry to study its various properties such as structure, surface morphology, thermal stability, dielectric properties, ionic conductivity, and electrochemical stability window for sodium ion battery (SIB) applications. The XRD analysis confirms two coexisting phases - tetragonal and cubic, with phase fractions of 0.69 and 0.31, respectively. The SEM study reveals the irregular shape and dense morphology of the solid electrolyte. On the other hand, TGA shows that the prepared solid electrolyte is suitable for high temperature battery applications. The ionic and transport studies confirm that the synthesized Na11Sn2AsS12 is purely ionic in nature, with ionic conductivity found to be 1.14×10-4 S cm-1 and negligible electronic conductivity 1/4 1.43×10-10 S cm-1 at room temperature. Furthermore, the detailed ionic conduction mechanism is studied using temperature and frequency-dependent AC impedance analysis. In addition, the synthesized solid electrolyte Na11Sn2AsS12 exhibits a wide electrochemical window ( 1/47.0 V) and a high diffusion coefficient ( 1.3×10-7 cm2 s-1) showing suitable electrolyte properties for solid-state SIB applications. © 2022 IOP Publishing Ltd.
Electrochemical investigation of double layer surface-functionalized Li-NMC cathode with nano-composite gel polymer electrolyte for Li-battery applications
(Elsevier Ltd, 2022) Shishir K. Singh; Dimple P. Dutta; Himani Gupta; Nitin Srivastava; Raghvendra Mishra; Dipika Meghnani; Rupesh K. Tiwari; Anupam Patel; Anurag Tiwari; Rajendra K. Singh
A long cycle-stability and safety is key requirement for the large-scale application of rechargeable Li-batteries. In this study, a thin double-layer (reduce graphene oxide and Li2MoO4) coated Li-NMC111 cathode is successfully synthesized which delivers improved electrochemical performance such as higher specific energy density and better rate capability, as compared to the pristine Li-NMC111. Furthermore, a freestanding/flexible nano-composite gel polymer electrolyte (NGPEs) is successfully prepared by solution cast technique and found suitable for high-temperature Li-battery applications. The developed 5 wt.% MCM-41 containing NGPE (NGPE#1) not only facilitates enhanced Li-ion conductivity of ∼4.4 ✗ 10−3 S cm−1 at 30 °C but also prevents uncontrolled lithium dendrite growth. The RGO-wrapped Li2MoO4@Li-NMC111 cathode with optimized NGPE#1 delivers high specific discharge capacity (∼211 mAh g − 1 at 0.2C and ∼157 mAh g − 1 at 0.5C) and specific energy density (∼728 mWh g − 1 at 0.2C and ∼520 mWh g − 1 at 0.5C) as compared to pristine Li-NMC111 cathode. Moreover, after 100 cycles, the discharge capacity of RGO-wrapped Li2MoO4@Li-NMC111 with optimized NGPE#1 is obtained ∼150 mAh g − 1 at 0.5C, with 75% capacity retention of the maximum capacity. In addition, at 70 °C, the specific discharge capacity of Li/RGO-wrapped Li2MoO4@Li-NMC111 cell with optimized NGPE#1 is obtained ∼186 mAh g − 1 at 0.5C. © 2022 Elsevier Ltd
Electrochemical Performance of High-Valence Mo6+ and Low-Valence Mn2+ Doped- Na3V2(PO4)3@C Cathode for Sodium-Ion Batteries
(John Wiley and Sons Inc, 2022) Dipika Meghnani; Shishir Kumar Singh; Nitin Srivastava; Rupesh Kumar Tiwari; Raghvendra Mishra; Anupam Patel; Anurag Tiwari; Rajendra Kumar Singh
The sodium superionic conductor (NASICON)-Na3V2(PO4)3 (NVP) is an attractive cathode for sodium-ion batteries, which is still confronted with limited rate performance due to its low electronic conductivity. In this paper, a chemical strategy is adopted to partially replace V3+ of the NVP framework by low-valence Mn2+ and high-valence Mo6+ substitution. The crystal structure, sodium-ion diffusion coefficient and electrochemical performance of Mn−Mo-doped [Na3.94V0.98Mo0.02Mn(PO4)3@C] cathode were investigated. X-ray diffraction confirmed the NASICON-type structure and XPS analysis confirmed the oxidation state of Mn and Mo in doped NVP cathode. The Na ion diffusion processes were inferred from Cyclic Voltammetry (CV), Galvanostatic intermittent titration technique (GITT) and Electrochemical Impedance Spectroscopy (EIS) measurement, which clearly show rapid Na-ion diffusion in NASICON-type cathode materials. The Mn−Mo-substituted NVP shows smoother charge-discharge profiles, improved rate performance (64.80 mAh/g at 1 C rate), better energy density (308.61 mWh/g) and superior Na-ion kinetics than that of unsubstituted NVP@C cathode. Their enhanced performance is attributed to large interstitial volume mainly created by high valence Mo6+ and enhanced capacity is attributed to the low valence Mn2+ doping. These results demonstrate that Mn−Mo-doped NVP cathode is strongly promising cathode material for sodium-ion batteries. © 2022 Wiley-VCH GmbH.
Electrochemical performance of Li-rich NMC cathode material using ionic liquid based blend polymer electrolyte for rechargeable Li-ion batteries
(Elsevier Ltd, 2020) Nitin Srivastava; Shishir Kumar Singh; Himani Gupta; Dipika Meghnani; Raghvendra Mishra; Rupesh K. Tiwari; Anupam Patel; Anurag Tiwari; Rajendra Kumar Singh
In this paper, synthesis of lithium rich nickel manganese cobalt oxide cathode material (Li1·2Ni0·6Mn0·1Co0·1O2) and ionic liquid (IL) based blend gel polymer electrolytes (BGPEs) are reported. Li1.2Ni0.6Mn0.1Co0.1O2 cathode material as well as BGPEs are prepared by solution combustion and solution casting technique, respectively. X-ray diffraction (XRD) technique clearly reveals that the cathode material is in pure phase, having well defined layered structure. Thermal, electrical and electrochemical properties of BGPEs are investigated by using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), impedance spectroscopy and linear sweep voltammetry (LSV). It is observed that 70 wt% IL containing BGPE provides maximum Li-ion conductivity (σLi∼1.1 mS cm−1), thermal (∼250 °C) and electrochemical stability (∼4.3 V vs. Li/Li+). Electrochemical analysis of the cell (Li/70 wt% BGPE/Li1·2Ni0·6Mn0·1Co0·1O2) provides well defined redox peaks corresponding to Ni2+/Ni4+ and it delivers specific discharge capacity of 166 mAh g−1 at 0.1 C-rate and 97% efficiency upto 140 cycle. © 2020 Elsevier B.V.
Enhanced Cyclic Stability of LiNi0.815Co0.15Al0.035O2 Cathodes by Surface Modification with BiPO4 for Applications in Rechargeable Lithium Polymer Batteries
(John Wiley and Sons Inc, 2021) Dipika Meghnani; Himani Gupta; Shishir K. Singh; Nitin Srivastava; Raghvendra Mishra; Rupesh K. Tiwari; Anupam Patel; Anurag Tiwari; Rajendra K. Singh
The effect of incorporating the ionic liquid (IL) N-methyl-N-propyl piperidinium bis(fluorosulfonyl)imide (PP13FSI) to a polymer electrolyte (PE) based on the polymer poly(ethylene oxide) (PEO)- lithium bis(fluorosulfonyl)imide (LiFSI) [PEO+20 wt.% LiFSI] is investigated. The concentration of PP13FSI IL is varied from 10 to 40 wt.% in the PEO+20 wt.% LiFSI system and the influences of the ionic conductivity, thermal stability, diffusion coefficient, and electrochemical stability are studied. The 40 wt.% IL containing PE shows good thermal stability ∼210 °C and high ionic conductivity, (Formula presented.), at 40 °C with a wide electrochemical stability window ∼4.7 V vs. Li/Li+ and high (Formula presented.) at 30 °C. Furthermore, the electronic conducting BiPO4 is coated on the LiNi0.815Co0.15Al0.035O2 (BiPO4@NCA) cathode by the liquid precipitation method. To investigate the structural and electrochemical properties of the pristine and BiPO4@NCA cathodes, XRD, SEM, TEM, and DSC as well as the electrochemical method are employed. The XRD results reveal a hexagonal layered structure without any impurity phase in BiPO4@NCA. The TEM investigations show that the BiPO4 layer (∼10 nm) is homogeneously coated on the NCA particles. The electrochemical testing showed an improvement in the cyclic performance of BiPO4@NCA with a capacity retention 94.64 % after 150 cycles, which is 8 % greater than that of the pristine NCA. © 2021 Wiley-VCH GmbH
Enhanced electrochemical performance of K0.67[Ni0.3Mn0.6Co0.1] O2 as a cathode material for secondary K-Ion batteries: Improved K-Ion insertion and reduced charge transfer barrier
(Elsevier B.V., 2024) Shitanshu Pratap Singh; Anupam Patel; Anurag Tiwari; Samriddhi; Vikas Yadav; Raghvendra Mishra; Rupesh Kumar Tiwari; Rajendra Kumar Singh
Potassium-ion batteries, with their high operating voltage and cost-efficiency, emerged as promising contenders for large-scale energy storage system. Nevertheless, the practical application is hindered by the significant challenges of achieving high capacity and good rate capability in cathodes. Herein, a novel layered oxide cathode, K0.67[Ni0.3Mn0.6Co0.1] O2 (KNMCO), has been synthesized via solid-state (S-KNMCO) and co-precipitation (C-KNMCO) routes. The X-Ray diffraction (XRD) peaks of KNMCO are identified in R3 m space group and well-indexed to hexagonal unit cell. The FE-SEM shows non-spherical morphologies for both samples. Additionally, high-resolution transmission electron microscopy (HR-TEM) images of the synthesized cathode materials shows the interlayer spacing of S-KNMCO is higher than that of C-KNMCO. Furthermore, the electrochemical performance of S-KNMCO and C-KNMCO is characterized using K-metal as anode and electrolyte KPF6 in EC/DEC (1:1, v/v). The S-KNMCO and C-KNMCO exhibit the maximum specific discharge capacity of ∼101 mAhg-1 and ∼66 mAhg-1 at the current rate of C/20 respectively. Additionally, these cells show the good rate capability and coulombic efficiency (∼94%). This research offers novel perspectives on the development of cathode substances for KIBs. © 2024 Elsevier B.V.
Enhanced Electrochemical Performance of Mg-Doped P2-Na0.7[Ni0.3Mn0.6Fe0.1]O2 Cobalt-Free Cathode Materials for Sodium-Ion Batteries
(American Chemical Society, 2024) Raghvendra Mishra; Anupam Patel; Anurag Tiwari; None Samriddhi; Shitanshu Pratap Singh; Vikas Yadav; Rupesh Kumar Tiwari; Rajendra Kumar Singh
In this study, cobalt-free P2-Na0.7[Ni0.3Mn0.6Fe0.1]O2 (NFM) cathode material is synthesized by a cost-effective and easy solid-state reaction route and its structure is stabilized by Mg-doping. The doping content is optimized by evaluating the physical and electrochemical performances of the series of Mg-doped (Mg = 0.05, 0.10, 0.15) cathode. The structural, morphological, and electronic properties of the cathode materials were characterized using various analytical techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Electrochemical measurements, including cyclic voltammetry (CV) and galvanostatic charge/discharge, were conducted to assess the electrochemical performance of pristine as well as doped cathode materials. It is observed that Mg-doped cathodes exhibited enhanced capacity and cycle life compared to the pristine counterpart, with NFMMg10 demonstrating the best performance. The optimized Mg-doped NFMMg10 sample shows a maximum discharge capacity of 184 mAh g-1 at 0.05C and 75% capacity retention over 1000 cycles. © 2024 American Chemical Society.
Fabrication and electrochemical characterization of lithium metal battery using IL-based polymer electrolyte and Ni-rich NCA cathode
(Springer Science and Business Media Deutschland GmbH, 2020) Dipika Meghnani; Himani Gupta; Shishir Kumar Singh; Nitin Srivastava; Raghvendra Mishra; Rupesh Kumar Tiwari; Anupam Patel; Anurag Tiwari; Rajendra Kumar Singh
Electrolytes with high Li+ transference number and good electrochemical stability are urgently needed for high-energy-density Li battery. In this paper, we present newly synthesized ionic liquid (IL)-based polymer electrolyte using polymer poly(ethylene oxide) (PEO), salt lithium bis(fluorosulfonly)imide (LiFSI), and IL 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide (BMPyTFSI) by solution cast technique. They show high Li+ transference number and good electrochemical and thermal stability. Also, nickel-rich layered cathode material LiNi0.90Co0.05Al0.05O2 (NCA) with good electrochemical performance for lithium secondary battery is successfully synthesized by Co-precipitation method. Using the optimized polymer electrolyte and NCA cathode, Li cell is prepared which shows initial discharge capacity of ~ 137 mAh g−1 at 0.1 C-rate and good Coulombic efficiency ~96.0% upto 125 cycles. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
Graphene-Based Metal-Ion Batteries
(Springer Science and Business Media Deutschland GmbH, 2024) Anupam Patel; Rajendra Kumar Singh
Graphene-based metal-ion batteries are a promising technology for energy storage due to the unique properties of graphene, such as its high surface area, good electrical conductivity, and mechanical strength. These batteries utilize graphene as a conductive additive or electrode material, which enhances their performance, energy density, and cycling stability. The metal ions used in these batteries can be lithium (Li), sodium (Na), potassium (K), or other multivalent ions (e.g., magnesium (Mg), zinc (Zn), aluminum (Al)), which are inserted and extracted from the graphene electrode during charging and discharging cycles. Graphene-based metal-ion batteries have shown excellent electrochemical performance, including high capacity, fast charge–discharge rates, and long cycle life. Furthermore, they have the potential for large-scale commercial applications due to their low cost, safety, and environmental friendliness. Despite the encouraging results, additional research is required to optimize the design and performance of graphene-based metal-ion batteries for energy storage applications. This chapter details the preparation, and characterization of graphene and its application for metal ion batteries. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
Hydrothermal assisted RGO wrapped fumed silica-sulfur composite for an advanced room-temperature sodium-sulfur battery
(Elsevier Ltd, 2024) Samriddhi; Anupam Patel; Anurag Tiwari; Shitanshu Pratap Singh; Vikas Yadav; Rupesh Kumar Tiwari; Rajendra Kumar Singh
A promising cathode material RGO/SiO2/S composite for an advanced room-temperature sodium‑sulfur (RT Na[sbnd]S) batteries is synthesized via incorporating nanosulfur into amorphous fumed silica wrapped with reduced graphene oxide (RGO) through the hydrothermal method. Fumed silica (SiO2) offers a high surface area beneficial for sulfur loading. In the presence of ethylenediamine (EDA), nanosulfur is incorporated into SiO2. Additionally, hydrothermal treatment of the prepared solution that contained EDA facilitates the optimal reduction of graphene oxide (GO) into nitrogen–doped interlinked, conducting, and porous RGO. EDA played a multifunctional role as nanosulfur precursor, a nitrogen source, as well as a reducing agent. The synthesized RGO/SiO2/S composite delivers a high initial discharge capacity of 923 mAh/g at 0.1 C-rate with excellent coulombic efficiency (∼99 %). During cycling, fumed silica in the composite buffers volume expansion that happens throughout the cycling process, while RGO in the composite enhances the conductivity of the sulfur. Additionally, the presence of nitrogen also improves the conductivity of the cathode material. © 2024 Elsevier Ltd
Impact of sintering temperature and ascertaining hopping bottlenecks for ions in sodium superionic conducting electrolyte for sodium-ion batteries
(Elsevier B.V., 2023) Anurag Tiwari; Dipika Meghnani; Raghvendra Mishra; Rupesh Kumar Tiwari; Anupam Patel; Rajendra Kumar Singh
Recently, sodium super-ionic conducting (NASICON) type solid electrolytes have gained attention for next generation batteries because of their high ionic conductivity, low cost, excellent chemical and electrochemical stability. Therefore, in the present study, NASICON-type solid electrolyte Na3Zr2Si2PO12 is synthesized by solution assisted-solid state reaction (SA-SSR) route. The electrolytes are sintered at three different temperatures, 1200 °C, 1250 °C and 1300 °C. The sintered electrolytes are characterized by various experimental techniques. The Rietveld refinement of X-ray diffraction pattern of prepared electrolytes revealed the monoclinic crystal structure. The 3-dimension hopping channel for sodium ion migration through triangular bottleneck area is identified. From complex impedance spectroscopy measurement, the highest bulk and grain boundary conductivity are found, ∼4.05mScm−1 and ∼0.31mScm−1, respectively, for the sample sintered at 1250 °C. The optimized electrolyte shows wide electrochemical stability (∼6.5 V) which is suitable for high voltage battery application. Using optimized electrolyte, sodium half-cell is fabricated with sodium metal as anode, and Na3V2P3O12 (NVP) as cathode. The assembled cell delivers maximum discharge capacity ∼101.6 and ∼84.5mAhg−1 at the current density 10 and 40mAg−1, respectively with good capacity retention (∼95.02%) upto 50 cycles. © 2023 Elsevier B.V.
Improved High Voltage Performance of Li-ion Conducting Coated Ni-rich NMC Cathode Materials for Rechargeable Li Battery
(American Chemical Society, 2021) Himani Gupta; Shishir K. Singh; Nitin Srivastava; Dipika Meghnani; Rupesh K. Tiwari; Raghvendra Mishra; Anupam Patel; Anurag Tiwari; Achchhe L. Saroj; Rajendra Kumar Singh
Recently, in lithium batteries, high-capacity Ni-rich cathode materials (LiNi0.8Mn0.1Co0.1O2) have gained tremendous attention. However, they also suffer from serious capacity degradation upon cycling, particularly at high voltage. To solve this problem, two strategies are proposed. The first one is the surface modification on the NMC811 cathode material with Li-ion-conducting Li3PO4. The second is the use of IL-based gel polymer electrolytes in Li metal batteries. Li3PO4 coating not only maintains the structure stability of the cathode but also suppresses the side reaction at the electrode-electrolyte interface. It also improves the Li+ ion conduction in the cathode material. Furthermore, in order to avoid the sensitivity of the cathode material toward H2O, CO2, and HF attack and solubility of transition metal ions in the electrolyte and enhance the cyclic performance of the Li battery, an IL-based gel polymer electrolyte is used. Mechanical stability of the polymer electrolyte can help suppress the lithium dendrite growth and overcome the issues of low electrochemical stability, leakage, and corrosion in liquid electrolytes. Electrochemical performance of the Li3PO4-coated NMC cathode material with the gel polymer electrolyte is tested at higher and lower upper cutoff voltages. Li batteries show a high discharge capacity of ∼182 mA h/g and an energy density of 606 mW h g-1 at C/10 current rate with almost stable cyclic stability up to 300 cycles. These tremendous features of polymer-based batteries with a surface-modified cathode material highlight its promising application in next-generation Li batteries. ©
Mitigating the Capacity Degradation by Ion-Electron-Conducting Dual-Layer Coating on a Layered Oxide Cathode Material for Sodium Ion Batteries
(American Chemical Society, 2023) Raghvendra Mishra; Shishir K. Singh; Nitin Srivastava; Rupesh K. Tiwari; Dipika Meghnani; Anupam Patel; Anurag Tiwari; Vimal K. Tiwari; Rajendra K. Singh
A high-capacity and long-life layered P2-Na0.7[Ni0.35Mn0.60Co0.05]O2 (NMC) cathode material, dually coated with Na-ion-conducting Na2SiO3 and electron-conducting RGO, has been successfully synthesized and tested for half-cell as well as full-cell applications. The first coating layer of Na2SiO3 provides a three-dimensional (3D) diffusion channel for Na-ion migration, while the second coating layer of RGO offers the electron-conducting pathways to enhance the charge transfer. Moreover, Si4+ migration in the NMC lattice during Na2SiO3 coating causes the enhancement in the interlayer spacing, which significantly increases the Na+-diffusion rate. The structural, morphological, electronic, and electrochemical analyses of the prepared cathode materials have been performed. The synergic effect of dual-layer modification and Si4+ doping not only protects the cathode particles but also improves the Na-ion kinetics as well as charge transfer rate, resulting in superior electrochemical performance. The dually surface-modified cathode shows a maximum discharge capacity of 171 mAh g-1 at ∼13 mA g-1 and 62 mAh g-1 at ∼1300 mA g-1 with 76% capacity retention and ∼98% coulombic efficiency over 500 cycles at 1C rate (260 mA g-1) for the half cell, while for the full cell, it delivers an initial discharge capacity of ∼91 mAh g-1 and 66% capacity retention over 1000 cycles at 1C rate. © 2023 American Chemical Society.
Molybdenum-Doped Li/Mn-Rich Layered Transition Metal Oxide Cathode Material Li1.2Mn0.6Ni0.1Co0.1O2with High Specific Capacity and Improved Cyclic Stability for Rechargeable Li-Batteries
(American Chemical Society, 2022) Nitin Srivastava; Shishir Kumar Singh; Dipika Meghnani; Raghvendra Mishra; Rupesh Kumar Tiwari; Anupam Patel; Anurag Tiwari; Rajendra Kumar Singh
A series of cathode materials, Li1.2Mn0.6-xNi0.1Co0.1MoxO2 (x = 0, 0.005, and 0.01), are synthesized via the sol-gel method. Structural characterization revealed that the Mo-doped material shows a well-defined ordered layered structure having less cation mixing. The Li1.2Mn0.59Ni0.1Co0.1Mo0.01O2 (LMRMo#0.01) cathode shows a high specific discharge capacity of 193.9 mAh g-1 with an initial Coulombic efficiency of 81.4% at room temperature and an excellent cyclic stability with a discharge capacity of ∼175.3 mAh g-1 (capacity retention 92.5%) after 250 cycles at 0.1 C. Substitution of Mn4+ by Mo6+ leads to low charge transfer resistance and enhancement in the stability of the layered structure, which result in outstanding electrochemical performance of the Mo-doped cathode. © 2022 American Chemical Society.
Multifaceted ethylenediamine and hydrothermal assisted optimum reduced GO-nanosulfur composite as high capacity cathode for lithium-sulfur batteries
(John Wiley and Sons Inc, 2022) Rupesh K. Tiwari; Shishir K. Singh; Himani Gupta; Nitin Srivastava; Dipika Meghnani; Raghvendra Mishra; Anupam Patel; Anurag Tiwari; Vimal K. Tiwari; Rajendra K. Singh
A high specific capacity conducting reduced graphene oxide nanosulfur nanocomposite (RGOSNC) cathode is synthesized via deposition of nanosulfur on graphene oxide (GO) through the hydrothermal treatment in the presence of multifaceted ethylenediamine (EDA) for improving the performance of lithium-sulfur battery (LiSB). The maximum utilization of active material (sulfur) is facilitated by the attachment of nanosulfur to GO via EDA, and further, optimum reduction of GO into conducting, porous and interconnected RGO is performed via hydrothermal treatment in the available solution having residual EDA. Therefore, GO is reduced in highly conducting RGO without the use of any external reducing agent; minimizing the chance of impurity in the synthesized RGOSNC. A three-dimensional interconnected porous conducting architecture with nitrogen (heteroatom) doping in RGO of RGOSNC with conductivity ∼1.83 S/cm assists easy electron transportation through conducting RGO network and stabilizes intermediate polysulfide to prevent loss of active material during the electrochemical performance. The synthesized RGOSNC cathode material delivers high initial specific capacities 1448 and 1040 mAh/g at 0.1 and 0.5 C, respectively. Prepared LiSB maintains ∼741 mAh/g retention over 100 cycles at 0.5 C with excellent Coulombic efficiency (∼99%). © 2021 The Authors. Electrochemical Science Advances published by Wiley-VCH GmbH.
Nitrogen-Doped Bioderived Mesoporous Hard Carbon as a Promising Anode for Long-Life Sodium-Ion Battery
(American Chemical Society, 2024) Anupam Patel; Raghvendra Mishra; Rupesh Kumar Tiwari; Anurag Tiwari; None Samriddhi; Shitanshu Pratap Singh; Vikas Yadav; Rajendra Kumar Singh
The recent development of energy storage systems that combine high efficiency with the possibility of inexpensive application is required in order to satisfy the ever-increasing demand for energy around worldwide. The development of sustainable electrode materials with enhanced capacity plays a pivotal role in advancing these energy storage systems. It is noteworthy that carbon-based materials have shown great potential as very promising options for fulfilling the role of negative electrode materials in sodium-ion batteries (SIBs). However, the electrochemical performance can be improved through the doping of nitrogen into carbonaceous materials. In this work, we have synthesized successfully activated Aegle marmelos hard carbon (AC-AMHC) and nitrogen-doped AC-AMHC as anodes for SIBs. The AC-AMHC and nitrogen-doped activated AMHC electrodes exhibit specific discharge capacities of ∼177 and ∼207 mA h g-1, respectively, at a current density of 10 mA g-1. The AC-AMHC and nitrogen-doped AC-AMHC electrodes exhibit outstanding cycling stability, maintaining high reversible capacities of ∼47 and ∼66 mA h g-1 at 500 mA g-1 up to 2000 cycles. Subsequently, a nitrogen-doped AC-AMHC anode and NVP cathode are used to fabricate a Na-ion full cell, which achieves a specific discharge capacity of ∼67 mA h g-1 at a C/10 rate. © 2024 American Chemical Society.