Natural graphite coated with Li2SiO3–Li2CO3-CNTs composite by solvothermal synthesis for high-performance sulfide-based all-solid-state lithium batteries

Abstract

Natural graphite is used as the anode material for sulfide-based all-solid-state lithium batteries, but the sulfide solid electrolyte causes problems with the natural graphite, the performance of which needs to be improved. Natural graphite coated with a Li₂SiO₃ and Li₂CO₃ composite was prepared by solvothermal synthesis at 650 °C for sulfide-based all-solid-state lithium batteries. The coating was intended to prevent decomposition of the solid electrolyte at low potential, cracking of the graphite or solid electrolyte, and separation of the bond between the graphite and solid electrolyte as a result of volume expansion and shrinkage during insertion and desorption of lithium ions into the graphite. Coating natural graphite with the Li₂SiO₃ and Li₂CO₃ composite improved the capacity retention rate after the 100th charging, and the addition of carbon nanotubes to the composite improved the rate characteristics. This study demonstrates that high-performance natural graphite can be developed as an anode material for sulfide-based all-solid-state lithium batteries.