Efficient Ion Percolating Network for High-Performance All-Solid-State Cathodes

All-solid-state lithium batteries (ASSLBs) face critical challenges of low cathode loading and poor rate performances, which handicaps their energy/power densities. The widely-accepted aim of high ionic conductivity and low interfacial resistance seems insufficient to overcome these challenges. Here, it is revealed that an efficient ion percolating network in the cathode exerts a more critical influence on the electrochemical performance of ASSLBs. By constructing vertical alignment of Li_0.35La_0.55TiO₃ nanowires (LLTO NWs) in solid-state cathode through magnetic manipulation, the ionic conductivity of the cathode increases twice compared with the cathode consisted of randomly distributed LLTO NWs. The all-solid-state LiFePO₄/Li cells using poly(ethylene oxide) as the electrolyte is able to deliver high capacities of 151 mAh g^-1 (2 C) and 100 mAh g^-1 (5 C) at 60 °C, and a room-temperature capacity of 108 mAh g^-1 can be achieved at a charging rate of 2 C. Furthermore, the cell can reach a high areal capacity of 3 mAh cm^-2 even with a practical LFP loading of 20 mg cm^-2. The universality of this strategy is also presented showing the demonstration in LiNi_0.8Co_0.1Mn_0.1O₂ cathodes. This work offers new pathways for designing ASSLBs with improved energy/power densities.