Lithiation mechanism of antimony chalcogenides (Sb2X3; X = S, Se, Te) electrodes for high-capacity all-solid-state Li-ion battery

All-solid-state Li-ion batteries are considered as next-generation batteries, which provide safer operation by replacing the flammable liquid electrolyte by solid electrolyte. Developing these batteries using high capacity anode materials is warranted with the increasing demand of the energy sector. Among all the anode materials, alloying-type anode materials are very attractive due to their high gravimetric as well as volumetric capacities, but they show large volume expansion which can be buffered by mixing different materials. Herein, all-solid-state Li-ion batteries were prepared using Sb chalcogenide composites as electrode materials, and the detailed electrochemical reaction mechanism for the lithiation/delithiation has been established using cyclic voltammetry (CV), electrochemical charge-discharge profiling, electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The lithiation reaction for all the composites was found to be conversion reaction in the first step (Sb <-> Li2X and Sb) followed by alloying reaction in the second step (Sb <-> Li3Sb), which is similar to that for liquid electrolyte case. All the composites showed the high volumetric capacity of >4000 mAh/cm(3) in the first cycle, which reduced down to similar to 1500-2000 mAh/cm(3) after 100 cycles. This 50% retained capacity is higher in comparison to conventional carbon electrode as well as previously reported works on similar materials. The coulombic efficiency for all the composites was found nearly 99% after initial 10 cycles. The highest energy density was found as 344 Wh/kg for Sb2S3 composite after 100 cycles (765 Wh/kg in the first cycle), which nearly equals to the target values and makes these composites suitable for the future Li-ion battery.

Automated summary

All-solid-state Li-ion batteries using Sb chalcogenide composites as electrode materials exhibit high volumetric capacity, retained capacity, and energy density, making them suitable for future Li-ion batteries. The lithiation mechanism involves conversion and alloying reactions similar to liquid electrolyte cases, with a high coulombic efficiency of nearly 99% after initial cycles. The composites show potential as promising candidates for advanced energy storage systems.