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

Cheng, Guangzeng; Sun, Hao; Wang, Haoran; Ju, Zhengyu; Zhu, Yue; Tian, Weiqian; Chen, Jingwei; Wang, Huanlei et al. · Adv Mater · 2024

basic_science · Level V

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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 Li<sub>0.35</sub>La<sub>0.55</sub>TiO<sub>3</sub> 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 LiFePO<sub>4</sub>/Li cells using poly(ethylene oxide) as the electrolyte is able to deliver high capacities of 151 mAh g<sup>-1</sup> (2 C) and 100 mAh g<sup>-1</sup> (5 C) at 60 °C, and a room-temperature capacity of 108 mAh g<sup>-1</sup> can be achieved at a charging rate of 2 C. Furthermore, the cell can reach a high areal capacity of 3 mAh cm<sup>-2</sup> even with a practical LFP loading of 20 mg cm<sup>-2</sup>. The universality of this strategy is also presented showing the demonstration in LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2</sub> cathodes. This work offers new pathways for designing ASSLBs with improved energy/power densities.