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

Abstract 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 Cu 2 SnS 3 as a model active material, such a kind of solid‐state Cu 2 SnS 3 @graphene‐Li 7 P 3 S 11 nanocomposite cathodes are synthesized, where 5–10 nm Cu 2 SnS 3 nanoparticles homogenously anchor on the graphene nanosheets, while the Li 7 P 3 S 11 electrolytes uniformly coat on the surface of Cu 2 SnS 3 @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‐Cu 2 SnS 3. The Cu 2 SnS 3 @graphene‐Li 7 P 3 S 11 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 Cu 2 SnS 3 @graphene‐Li 7 P 3 S 11 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.