Elucidating the electrochemical reaction mechanism of lithium-rich antiperovskite cathodes for lithium-ion batteries as exemplified by (Li2Fe)SeO

We report in the context of lithium-rich antiperovskite cathode materials outstanding electrochemical properties of (Li2Fe)SeO, which for the first time was synthesized via direct ball-milling. The unique structured material displays an electrochemical cycling performance of 250 mA h g(-1) at 0.1C when used as a cathode in lithium-ion batteries. Comprehensive electrochemical analysis combined with detailed transmission electron microscopy studies reveal that, above 2.5 V, the multi electron storage mechanism involves conversion of (Li2Fe)SeO to Fe1-xSex. Our results furthermore demonstrate the general relevance of our findings to the whole class of antiperovskite cathode materials and present a route to strongly enhance their cell performance by avoiding the degradation path deciphered by our studies.

Automated summary

We report the outstanding electrochemical properties of (Li2Fe)SeO, a lithium-rich antiperovskite cathode material synthesized for the first time via direct ball-milling. It exhibits a cycling performance of 250 mA h g(-1) at 0.1C when used as a cathode in lithium-ion batteries. The conversion of (Li2Fe)SeO to Fe1-xSex above 2.5 V suggests a multi-electron storage mechanism.