Among the germanium-based composites, germanium phosphide (GeP) is a promising anode material for lithium-ion batteries (LiBs) because of its good electronic conductivity, low binding energy and high theoretical energy density. Nevertheless, the severe volume variation and sluggish reaction kinetics hindered its applications. To solve the above issues, this work come up with a killer idea that inspired by the free volume theory of polymers, which was mainly involved creation of free volume into GeP matrix. Specifically, structural design that elaborately deals with severe aggregation while helps alleviating volume expansion and contraction of GeP have being made by a facile ball milling-assisted in-situ generation of free expansion volume. Compared with pristine GeP and direct ball milled GeP, the addition of NaCl as grinding agent plays a very positive role on generating free volume space in flake-like GeP particles, which was assembled by numerous amorphous GeP granules. In this way, the as obtained GeP particles exhibited enhanced reversible capacity, improved cyclability and rate performance (883 mAh g⁻¹ at 0.2 C after 100th cycle, and 680 mAh g⁻¹ at 2 C) when served as anode material in LiBs. This study highlights a highly efficient and cost effective approach in advancing the high performance GeP towards practical applications for energy storage.

在锗基复合材料中，磷化锗（GeP）具有良好的电子导电性、低结合能和高理论能量密度，是一种很有前途的锂离子电池（LiBs）负极材料。然而，严重的体积变化和缓慢的反应动力学阻碍了其应用。为了解决上述问题，这项工作提出了一个受聚合物自由体积理论启发的杀手级想法，主要涉及在 GeP 矩阵中创建自由体积。具体而言，通过简单的球磨辅助原位生成自由膨胀体积，精心处理严重聚集同时有助于减轻 GeP 体积膨胀和收缩的结构设计。与原始 GeP 和直接球磨 GeP 相比，添加 NaCl 作为研磨剂对在片状 GeP 颗粒中产生自由体积空间起着非常积极的作用，该颗粒由许多无定形 GeP 颗粒组装而成。通过这种方式，所获得的 GeP 颗粒表现出增强的可逆容量、改善的循环性能和倍率性能（883 毫安 克^-1在第100次循环后0.2 C，和680 毫安 克^-1时在LIBS阳极材料投放在2℃）。这项研究强调了一种高效且具有成本效益的方法，可以将高性能 GeP 推向储能的实际应用。