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

• Published in: Advanced materials (Weinheim) 2024-05, Vol.36 (21), p.e2312927-n/a
• Main Authors: Cheng, Guangzeng, Sun, Hao, Wang, Haoran, Ju, Zhengyu, Zhu, Yue, Tian, Weiqian, Chen, Jingwei, Wang, Huanlei, Wu, Jingyi, Yu, Guihua
• Format: Article
• Language: English
• Subjects: Cathodes; composite cathodes; Electrochemical analysis; Electrolytic cells; Electrons; Ethylene oxide; Ion currents; ion transport pathways; Lithium batteries; Nanowires; Percolation; Polyethylene oxide; solid‐state battery
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202312927

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 Li0.35La0.55TiO3 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 LiNi0.8Co0.1Mn0.1O2 cathodes. This work offers new pathways for designing ASSLBs with improved energy/power densities. A magnetic‐field‐induced alignment strategy is explored to effectively control the orientation of Li0.35La0.55TiO3 nanowires (LLTO NWs) in solid‐state composite cathodes. Simulation calculations combined with experiments reveal the merits of vertically aligned LLTO NWs in the composite cathode alleviating the ion concentration gradient and enhancing the active material utilization which is promising for achieving high‐performance ASSLBs.