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Crystallization of olivine and maricite structures in polyanionic groups flourishing with splendid electrochemical performance is tedious, and the preparation of these materials involves ion exchan...

Sulfur (S)/silicon dioxide (SiO2)/multiwalled carbon nanotube (MWCNT) ternary composites with potential application in high-performance lithium-sulfur (Li-S) batteries have been prepared by a heat treatment method. The S/SiO2/MWCNT composite with MWCNT content of 20 wt.% exhibited efficient electrochemical performance for use as a cathode in Li-S batteries, with initial discharge capacity of 926 mAh g−1 and coulombic efficiency of 99% at 0.2 C rate. A discharge capacity of 501 mAh g−1 was observed after 300 cycles with a decay rate of 0.15% per cycle. The average capacity retention was found to be 81.7% and 54.1% after 100 cycles and 300 cycles, respectively. These results demonstrate that a high content of MWCNT improved the electronic conductivity while the SiO2/MWCNT matrix represents a strong physical and chemical host for the polysulfides and active material. This study determines the combined effect of silica and MWCNT to improve the performance of the sulfur cathode.

Lithium iron orthosilicate (LFS) cathode can be prepared via the polyol-assisted ball milling method with the incorporation of carbon derived from eggshell membrane (ESM) for improving inherent poor electronic conduction. The powder X-ray diffraction (XRD) pattern confirmed the diffraction peaks without any presence of further impure phase. Overall, 9 wt.% of carbon was loaded on the LFS, which was identified using thermogravimetric analysis. The nature of carbon was described using parameters such as monolayer, and average surface area was 53.5 and 24 m2 g&minus, 1 with the aid of Langmuir and Brunauer&ndash, Emmett&ndash, Teller (BET) surface area respectively. The binding energy was observed at 285.66 eV for C&ndash, N owing to the nitrogen content in eggshell membrane, which provides more charge carriers for conduction. Transmission electron microscopy (TEM) images clearly show the carbon coating on the LFS, the porous nature of carbon, and the atom arrangements. From the cyclic voltammetry (CV) curve, the ratio of the anodic to the cathodic peak current was calculated as 1.03, which reveals that the materials possess good reversibility. Due to the reversibility of the redox mechanism, the material exhibits discharge specific capacity of 194 mAh g&minus, 1 for the first cycle, with capacity retention and an average coulombic efficiency of 94.7% and 98.5% up to 50 cycles.

In the present study, Li2FeSiO4 (LFS) cathode material has been prepared via a modified polyol method. The stabilizing nature of polyol solvent was greatly influenced to reduce the particle size (~50 nm) and for coating the carbon on the surface of the as-mentioned materials (~10 nm). As-prepared nano-sized Li2FeSiO4 material deliver initial discharge capacity of 186 mAh&middot, g&minus, 1 at 1C with the coulombic efficiency of 99% and sustain up to 100 cycles with only 7 mAh&middot, 1 is the difference of discharge capacity from its 1st cycle to 100th cycle. The rate performance illustrates the discharge capacity 280 mAh&middot, 1 for lower C-rate (C/20) and 95 mAh&middot, 1 for higher C-rate (2C).