Tuning the electrochemical properties by anionic substitution of Li-rich antiperovskite (Li₂Fe)S_1−xSe_xO cathodes for Li-ion batteries

Abstract

A tunable redox potential and electrochemical performance are realized by anionic substitution of S by Se for the Li-rich antiperovskite (Li2Fe)SO cathode.

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

“…For both materials at hand, the two initial oxidation peaks O 1 and O 2 appear at about ∼2.3 V and 2.5 V and signal the two-stage cationic Fe 2+ to Fe 3+ oxidation process. 2,13 We note the lower voltage of these features compared to (Li 2 Fe)SeO-SSR. 3 This shi towards lower voltages can be attributed to lower polarization due to the smaller particle sizes and corresponding smaller diffusion path length for Li + .…”

“…[34][35][36] An anionic reaction of the contained chalcogen is proposed to take place in the highvoltage region O 2 , O * . 2,13 During the rst intercalation (discharge), both samples display distinct reduction peaks (R 1 , R 2 , R 3 ) in the CV. Note, the lower distinctness and the higher broadness of the peaks in the cyclic voltammogram of (Li 2 Fe)SeO-BM can, in accordance with the XRD data, be attributed to the lower crystallinity.…”

“…In the previous literature, lithium storage was discussed as a multielectron storage process involving cationic and anionic contributions. 2,6,13 In particular, (Li 2 Fe)SO, (Li 2 Fe)SeO, and the mixed systems (Li 2 Fe)S 1−x Se x O have been studied. 2,3,13 By means of in situ XAS, in situ XRD and Mössbauer spectroscopy, the rst two oxidation peaks in the cyclovoltammograms were attributed to the oxidation of Fe 2+ to Fe 3+ .…”

“…2,6,13 In particular, (Li 2 Fe)SO, (Li 2 Fe)SeO, and the mixed systems (Li 2 Fe)S 1−x Se x O have been studied. 2,3,13 By means of in situ XAS, in situ XRD and Mössbauer spectroscopy, the rst two oxidation peaks in the cyclovoltammograms were attributed to the oxidation of Fe 2+ to Fe 3+ . 2 In contrast, the exact anionic process associated with sulfur/selenium has not been fully elucidated despite many investigations.…”

Mechanochemical synthesis of Li-rich (Li2Fe)SO cathode for Li-ion batteries

“…1,3 The recently reported (Li 2 Fe)SO cathode, which belongs to the Li-rich antiperovskites with the general formula (Li 2 TM)ChO (TM = Fe, Mn and Ch = S, Se), is a promising alternative with superior theoretical and practical specific capacities due to its multi-electron storage through cationic and anionic redox processes. [4][5][6][7] In addition, the antiperovskite (Li 2 Fe)SO has low cost and toxicity compared to Co-containing cathode materials, which can reduce the cost and environmental footprint of Li-ion batteries. [8][9][10][11] Numerous studies show approaches for recycling of Li-ion batteries including sulfur-containing materials as well.…”