Browsing by Author "Shitanshu Pratap Singh"

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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.
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
Dynamics of ionic liquid-polymer gel membranes—Insight from NMR relaxometry for [BMIM][BF4]-PVDF-HFP systems
(American Institute of Physics, 2024) Shitanshu Pratap Singh; Elżbieta Masiewicz; Rajendra Kumar Singh; Sujeet Kumar Chaurasia; Danuta Kruk
1H spin-lattice relaxation experiments have been performed for ionic liquid-polymer gel membranes, including 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) with different proportions. The experiments have been performed in a broad range of resonance frequencies (from about 5 Hz to 40 MHz) vs temperature and complemented with analogous studies for [BMIM][BF4] in bulk as a reference. A model of the relaxation processes in the membranes has been proposed. The model includes two relaxation contributions. One of them corresponds to the concept of restricted, two-dimensional translation diffusion with a residence lifetime, while the second one has the form characteristic of polymers (mathematically similar to the limiting behavior of two-dimensional translation diffusion with a very long residence lifetime). The extensive dataset has been consistently interpreted in terms of the model, revealing two dynamical processes on the time scales of 10−7 s (for the second relaxation contribution) and 10−9 s (for the first one). The relationship of these relaxation contributions to the motion of the polymer or ionic liquid-polymer complexes and to the translation diffusion of BMIM cations in the matrix has been discussed. © 2024 Author(s).
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.
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
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.
Sponge-like porous sustainable hard carbon as an efficient anode for sodium-ion batteries
(Elsevier Ltd, 2025) Anupam Patel; Anurag Tiwari; Samriddhi; Shitanshu Pratap Singh; Vikas G. Yadav; Tanya Jaiswal; Danuta Kruk; Ranjith Krishna Pai; Rajendra K. Singh
Renewable, cost-effective, eco-friendly, and abundant biodegradable waste has emerged as a promising resource for developing hard carbon (HC) anode materials for rechargeable sodium-ion batteries (SIBs). This study focuses on synthesizing HC anode materials from mango leaves using hydrothermal carbonization process, and thereafter pyrolysis at 900 °C and 1000 °C. The synthesized HC shows the spongelike morphology along with large specific surface area (88.3 m² g−1). The resulting materials pyrolyzed at 900 °C and 1000 °C, designated as Mango (Mangifera indica) Leaves Hard Carbon (MLHC-900) and (MLHC-1000) respectively, deliver impressive discharge capacities per unit mass of approximately 241 mAh g−1 and 215 mAh g−1 at a current density of 10 mA g−1, respectively. After 1200 cycles at a current density 1000 mA g−1, the MLHC-900 demonstrated superior capacity retention compared to MLHC-1000. These results signify the potential of using biodegradable waste utilizing hydrothermal carbonization to fabricate efficient HC anodes for SIBs. © 2025 Elsevier Ltd
Surface-Coated NaNi0.815Co0.15Al0.035O2 Cathode-Based Sodium-Ion Batteries with Enhanced Performance
(American Chemical Society, 2024) Dipika Meghnani; Nitin Srivastava; Rupesh Kumar Tiwari; Raghvendra Mishra; Anupam Patel; Anurag Tiwari; None Samriddhi; Shitanshu Pratap Singh; Vikas Yadav; Rajendra Kumar Singh
The cathode material is the main component for stabilizing sodium-ion batteries, and there is an urgent need for cathode materials with long-term cyclability and better capacity retention. Surface stabilization is one approach that can improve the performance of the cathode materials. This study focuses on modifying the surface of NaNi0.815Co0.15Al0.035O2 (Na-NCA) cathode materials using the hydrothermal method with different amounts (0.5, 1.0, and 1.5 wt %) of Na-ion conducting Na3PO4 by the liquid precipitation method and its impact on the electrochemical performance of Na-NCA has been investigated. Transmission electron microscopy analysis confirms the coating layer of Na3PO4 with thicknesses ∼2.2 and 20 nm for Na3PO4@0.5 and Na3PO4@1, respectively, and varying thicknesses (∼20-10 nm) is observed for Na3PO4@1.5 cathodes. Electrochemical testing indicates that the sample with a thickness of ∼2.2 nm shows a uniform coating layer, high discharge capacity, better kinetics of Na+ ions, and capacity retention than that of pristine Na-NCA. © 2023 American Chemical Society.