Construction of 3D Electronic/Ionic Conduction Networks for All-Solid-State Lithium Batteries

High and balanced electronic and ionic transportation networks with nanoscale distribution in solid-state cathodes are crucial to realize high-performance all-solid-state lithium batteries. Using Cu₂ SnS₃ as a model active material, such a kind of solid-state Cu₂ SnS₃ @graphene-Li₇ P₃ S₁₁ nanocomposite cathodes are synthesized, where 5-10 nm Cu₂ SnS₃ nanoparticles homogenously anchor on the graphene nanosheets, while the Li₇ P₃ S₁₁ electrolytes uniformly coat on the surface of Cu₂ SnS₃ @graphene composite forming nanoscaled electron/ion transportation networks. The large amount of nanoscaled triple-phase boundary in cathode ensures high power density due to high ionic/electronic conductions and long cycle life due to uniform and reduced volume change of nano-Cu₂ SnS_3. The Cu₂ SnS₃ @graphene-Li₇ P₃ S₁₁ cathode layer with 2.0 mg cm^-2 loading in all-solid-state lithium batteries demonstrates a high reversible discharge specific capacity of 813.2 mAh g^-1 at 100 mA g^-1 and retains 732.0 mAh g^-1 after 60 cycles, corresponding to a high energy density of 410.4 Wh kg^-1 based on the total mass of Cu₂ SnS₃ @graphene-Li₇ P₃ S₁₁ composite based cathode. Moreover, it exhibits excellent rate capability and high-rate cycling stability, showing reversible capacity of 363.5 mAh g^-1 at 500 mA g^-1 after 200 cycles. The study provides a new insight into constructing both electronic and ionic conduction networks for all-solid-state lithium batteries.