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

Abstract

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 Li0.35 La0.55 TiO3 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 151mAhg-1 (2C) and 100mAhg-1 (5C) at 60°C, and a room-temperature capacity of 108mAhg-1 can be achieved at a charging rate of 2C. Furthermore, the cell can reach a high areal capacity of 3mAhcm-2 even with a practical LFP loading of 20mgcm-2 . The universality of this strategy is also presented showing the demonstration in LiNi0.8 Co0.1 Mn0.1 O2 cathodes. This work offers new pathways for designing ASSLBs with improved energy/power densities.