Sagar Mitra

High-Rate and High-Energy-Density Lithium-Ion Battery Anode Containing 2D MoS2 Nanowall and Cellulose Binder

Electrochemically stable molybdenum disulfide (MoS₂) with a two-dimensional nanowall structure is successfully prepared by a simple two-step synthesis method followed by thermal annealing at 700 °C in a reducing atmosphere. MoS₂ nanowalls provide a better electrochemical performance and stability when cellulose (CMC) binder is used instead of the usual PVDF. The electrodes exhibit a high specific discharge capacity of 880 mA h g⁻¹ at 100 mA g⁻¹ without any capacity fading for over 50 cycles. The electrode also exhibits outstanding rate capability with a reversible capacity as high as 737 mA h g⁻¹ and 676 mA h g⁻¹ at rates of 500 mA g⁻¹ and 1000 mA g⁻¹ at 20 °C, respectively. The excellent electrochemical stability and high specific capacity of the nano structured materials are attributed to the two-dimensional nanowall morphology of MoS₂ and the use of cellulose binder. These results are the first of its kind to report a superior stability using bare MoS₂ as an active material and CMC as a binder.

Electrochemical capacitors with plasticized gel-polymer electrolytes

Solid electrolytes which comprise lithium and magnesium triflate ionic salts in polyacrylonitrile (PAN)-based gels are used to fabricate electrochemical double-layer capacitors in conjunction with ethylene carbonate (EC) and propylene carbonate (PC) as plasticizers and high-density graphite (HDG) as polarizable electrodes. The conductivity of the solid electrolytes is around

Exfoliated MoS2 Sheets and Reduced Graphene Oxide-An Excellent and Fast Anode for Sodium-ion Battery.

10 ^-^3 S cm ^-^1

Tin sulfide (SnS) nanorods: structural, optical and lithium storage property study

at ambient temperatures. Composites which consist of PAN+EC+PC+electrolyte are electrochemically stable over a wide potential range. Cells of the type: HDG/PAN–EC–PC–Li and Mg-triflate/HDG exhibit single-electrode discharge capacitance values of 480 and 383

Improved electrochemical performance of SnO2-mesoporous carbon hybrid as a negative electrode for lithium ion battery applications.

\mu F cm^-^2

Atomic Layer Deposited Molybdenum Nitride Thin Film: A Promising Anode Material for Li Ion Batteries

, respectively, with attractive charge–discharge characteristics.

Electrochemical activity of α-MoO3 nano-belts as lithium-ion battery cathode

Three dimensional (3D) MoS2 nanoflowers are successfully synthesized by hydrothermal method. Further, a composite of as prepared MoS2 nanoflowers and rGO is constructed by simple ultrasonic exfoliation technique. The crystallography and morphological studies have been carried out by XRD, FE-SEM, TEM, HR-TEM and EDS etc. Here, XRD study revealed, a composite of exfoliated MoS2 with expanded spacing of (002) crystal plane and rGO can be prepared by simple 40 minute of ultrasonic treatment. While, FE-SEM and TEM studies depict, individual MoS2 nanoflowers with an average diameter of 200 nm are uniformly distributed throughout the rGO surface. When tested as sodium-ion batteries anode material by applying two different potential windows, the composite demonstrates a high reversible specific capacity of 575 mAhg−1 at 100 mAg−1 in between 0.01 V–2.6 V and 218 mAhg−1 at 50 mAg−1 when discharged in a potential range of 0.4 V–2.6 V. As per our concern, the results are one of the best obtained as compared to the earlier published one on MoS2 based SIB anode material and more importantly this material shows such an excellent reversible Na-storage capacity and good cycling stability without addition of any expensive additive stabilizer, like fluoroethylene carbonate (FEC), in comparison to those in current literature.

Excellent electrochemical performance of tin monosulphide (SnS) as a sodium-ion battery anode

Tin mono-sulfide (SnS) nanorods (NRs) have been successfully synthesized through a solvothermal process using hydrated tin(II) chloride and sodium sulfide as precursors and N,N-dimethyl formamide (DMF) as solvent. The Reitveld refined powder X-ray diffraction (PXRD), Raman and 119Sn solid-state NMR experiments have confirmed the presence of a SnS phase with Pnma space group and a SnS2 phase with Pm1 space group as a minor impurity. HRTEM and HRSEM studies have confirmed the nanoparticle shape as nanorods (NRs). The growth of the NRs has been explained from the observation that by increasing the solvothermal temperature, nanorods grow preferentially in the [100] direction. Optical properties of the SnS nanorods were measured and it was found that all NRs have an indirect band gap in the range of 1.10 eV to 1.2 eV. The electrochemical properties for lithium storage (half-cell configuration) have been tested against Li/Li+ using conventional polyvinylidene fluoride (PVDF) binder and an eco-friendly, low cost binder, carboxy methyl cellulose (CMC). After fifty cycles of charge–discharge, the CMC binder electrode shows a superior electrochemical charge storage property of 591 mA h g−1 compared with 385 mA h g−1 for the PVDF binder electrode, at 160 mA g−1 current rate. At a high current rate of 350 mA g−1, the SnS NRs with the CMC binder shows a discharge capacity of 565 mA h g−1 after 50 cycles, therefore exhibiting excellent properties for a lithium battery anode as it can maintain a high capacity and coulombic efficiency continuously for 50 cycles.

Intercalation Anode Material for Lithium Ion Battery Based on Molybdenum Dioxide

To utilize the high specific capacity of SnO2 as an anode material in lithium-ion batteries, one has to overcome its poor cycling performance and rate capability, which result from large volume expansion (∼300%) of SnO2 during charging-discharging cycles. Hence, to accommodate the volume change during cycling, SnO2 nanoparticles of 6 nm diameter were synthesized specifically only on the outer surface of the mesopores, present within mesoporous carbon (CMK-5) particles, resulting in an effective buffering layer. To that end, the synthesis process first involves the formation of 3.5 nm SnO2 nanoparticles inside the mesopores of mesoporous silica (SBA-15), the latter being used as a template subsequently to obtain SnO2-CMK-5 hybrid particles. SnO2-CMK-5 exhibits superior rate capabilities, e.g. after 30 cycles, a specific discharge capacity of 598 mA h g(-1), at a current density of 178 mA g(-1). Electrochemical impedance spectroscopy reveals that the SnO2-CMK-5 electrode undergoes a significant reduction in solid-electrolyte interfacial and charge transfer resistances, with a simultaneous increase in the diffusion coefficient of lithium ions, all these in comparison to an electrode made of only SnO2 nanoparticles. This enhances the potential of using the SnO2-CMK-5 hybrid as a negative electrode, in terms of improved discharge capacity and cycling stability, compared to other electrodes, such as only SnO2 or only CMK-5.

Nickel ferrite as a stable, high capacity and high rate anode for Li-ion battery applications

Molybdenum nitride (MoNx) thin films are deposited by atomic layer deposition (ALD) using molybdenum hexacarbonyl [Mo(CO)6] and ammonia [NH3] at varied temperatures. A relatively narrow ALD temperature window is observed. In situ quartz crystal microbalance (QCM) measurements reveal the self-limiting growth nature of the deposition that is further verified with ex situ spectroscopic ellipsometry and X-ray reflectivity (XRR) measurements. A saturated growth rate of 2 Å/cycle at 170 °C is obtained. The deposition chemistry is studied by the in situ Fourier transform infrared spectroscopy (FTIR) that investigates the surface bound reactions during each half cycle. As deposited films are amorphous as observed from X-ray diffraction (XRD) and transmission electron microscopy electron diffraction (TEM ED) studies, which get converted to hexagonal-MoN upon annealing at 400 °C under NH3 atmosphere. As grown thin films are found to have notable potential as a carbon and binder free anode material in a Li ion battery. Under half-cell configuration, a stable discharge capacity of 700 mAh g(-1) was achieved after 100 charge-discharge cycles, at a current density of 100 μA cm(-2).