Efficient synthesis strategy of near-zero volume change materials for all-solid-state batteries operable under minimal stack pressure

Abstract

All-solid-state batteries are promising for energy storage applications because of the high ionic conductivity of solid electrolytes. Nevertheless, high stack pressure is required during operation to accommodate electrode volume changes and to maintain interfacial contact. Li_8/7Ti_2/7V_4/7O₂ (LTVO) has been reported as a dimensionally invariable high-capacity positive electrode material. While the synthesis of LTVO typically necessitates high-energy ball milling to produce nanosized particles with large surface areas, thereby mitigating the sluggish electrode kinetics inherent to disordered structures, this process is unsuitable for mass production. In this study, LTVO samples with different surface areas are synthesized by tuning synthesis temperatures and post-milling treatment conditions and employing solution-based synthesis methods. The optimized sample (∼20 m² g⁻¹) exhibits a large reversible capacity of ∼250 mA h g⁻¹, and can be synthesized using a scalable approach. Furthermore, the optimized LTVO enables stable operation of all-solid-state batteries under minimal stack pressure (<0.5 MPa).