Environmentally friendly ball milling for particle modification of anti-perovskite cathodes for Lithium-ion batteries applications

The pursuit of a clean energy future requires the development of next-generation battery technology. To that aim, studies on Li-based systems to boost the gravimetric capacity of the cathode are at the forefront of battery chemistries capable of multielectron redox processes. Lithium-rich Anti perovskite cathode materials with cationic and anionic redox bi-functionality are promising candidates for lithium-ion batteries (LIB) with high energy density. Here, we report the synthesis of Anti perovskite (Li2Fe)SeO by means of a one-step solid-state method which results in phase pure material consisting of predominantly micrometre-sized particles. Thermodynamic investigations confirm the high thermal stability of (Li2Fe)SeO up to 1200 ◦C without any indication of phase decomposition. The distinct structured material exhibits a cycling capacity of 250 mAh g−1 at 0.1 C as a cathode in lithium-ion batteries. Through thorough electrochemical analysis and in-depth transmission electron microscopy investigations, it is discovered that the multi-electron storage mechanism of this material involves the transformation of (Li2Fe)SeO to Fe1−xSex when the voltage exceeds 2.5 V. Moreover, our findings have broader implications for all antiperovskite cathode materials, illustrating a means to significantly improve their performance by circumventing the degradation process revealed in our research.