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 Cu2SnS3 as a model active material, such a kind of solid‐state Cu2SnS3@graphene‐Li7P3S11 nanocomposite cathodes are synthesized, where 5–10 nm Cu2SnS3 nanoparticles homogenously anchor on the graphene nanosheets, while the Li7P3S11 electrolytes uniformly coat on the surface of Cu2SnS3@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‐Cu2SnS3. The Cu2SnS3@graphene‐Li7P3S11 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 Cu2SnS3@graphene‐Li7P3S11 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. Using Cu2SnS3 as a model active cathode material, Cu2SnS3@graphene‐Li7P3S11 nanocomposite cathode with nanoscaled 3D electronic/ionic conduction networks is achieved. The large amount of nanoscale triple‐phase boundaries between active material, carbon, and solid electrolyte can significantly enhance interfacial contact, reduce stress/strain, and maintain the structural integrity of electrode material, resulting in high power density and long cycle life all‐solid‐state lithium batteries.