Enhanced Cathode/Electrolyte Interface in Solid-state Li-metal Battery based on Garnet-type Electrolyte

Li/garnet/LiFePO 4 solid-state battery was fabricated. The cathode contains LiFePO 4 , Ketjen black, poly(vinylidene fluoride):LiTFSI polymer as active material, electric conductor and Li-ion conducting binder, respectively. Polyvinylpyrrolidone was added into the cathode to improve cathode/electrolyte interfacial performance. When combined with polyvinylpyrrolidone additive, poly(vinylidene fluoride):polyvinylpyrrol idone:LiTFSI blend forms, and the cathode/electrolyte interfacial resistance reduces from 10.7 kΩ to 3.2 kΩ. The Li/garnet/LiFePO 4 solid-state battery shows 80% capacity retention after 100 cycles at 30 °C and 0.05 C. This study offers a general strategy to improve cathode/electrolyte interfacial performance and may enable the practical application of solid-state Li-metal batteries.