Amorphous ZrCl4-Based Superionic Conductor as a Cost-Effective Solid Electrolyte for Batteries
Guangxing Zhang, Zhantao Liu, Yifan Ma, Jakub Pepas, Hang Xu, Rui Cai, Shuman Xia, Yong Ding, Jianming Bai, Hui Zhong, Yuanzhi Tang, Hailong ChenAbstract
Developing highly conductive and cost-effective solid electrolytes is essential for the commercialization of all-solid-state batteries (ASSBs). Zr-based halide electrolytes hold great promise due to their low estimated cost and high oxidation stability. However, the ionic conductivities of most of them are not high enough to enable moderate- and high-rate cycling of ASSBs. Here, fast ion transport is achieved in a group of cost-effective ZrCl4-based electrolytes via a design strategy to create highly disordered amorphous structures. Amorphous Li0.8ZrCl4(SO4)0.4, with a low estimated cost of $21 kg–1, achieves an ionic conductivity of 1.86 mS cm–1 at 25 °C. It also shows a high oxidation limit of 4.5 V vs Li/Li+ and good compatibility with high-voltage cathodes, as demonstrated by the stable cycling of ASSBs (73.7% capacity retention after 1000 cycles at 1 C). Synchrotron X-ray diffraction, pair distribution function analysis, and electrochemical impedance spectroscopy reveal that the outstanding conductivity of these amorphous electrolytes is closely related to their short-range and medium-range ordering, revealing new insights for designing high-performance, cost-effective solid electrolytes.