Exposure History and its Effect Towards Stabilizing Li Exchange Across Disordered Rock Salt Interfaces. Issue 20 (4th November 2021)

• Record Type: Journal Article
• Authors: Satish, Rohit; Wichmann, Lennart; Crafton, Matthew J.; Giovine, Raynald; Li, Linze; Ahn, Juhyeon; Yue, Yuan; Tong, Wei; Chen, Guoying; Wang, Chongmin; Clement, Raphäele J.; Kostecki, Robert
• Is Part Of: ChemElectroChem. Volume 8:Issue 20(2021)
• Page Start: 3982
• Page End: 3991
• Publication Date: 2021-11-04
• Subjects: disordered rock salt -- exposure history -- electrode/electrolyte interface -- surface modification -- surface passivation; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.202100891
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: The application of lithium rich disordered rock salts (DRX) as cathode materials has greatly expanded the materials space for high energy density cathodes. These materials are able to consistently achieve capacities higher than 250 m A h g - 1 via a complex percolation based intercalation mechanism. Most current DRX materials face significant capacity fade when cycled over an extended period. One of the factors responsible for this could be deleterious side effect of interface reactions between the electrode and electrolyte at high voltage. We aim to focus on one aspect of this interaction, i.e the effect of exposure to electrolyte on the surface and its effect on the electrochemical properties of L i 1 . 2 M n 0 . 625 N b 0 . 175 O 1 . 95 F 0 . 05 (LMNOF) powder. LMNOF was systematically treated in an electrolyte solution for varying periods of time at an elevated temperature. Treated samples exhibit surface layer modification (removal of F rich surface layer), leading to a 10 % improvement in the capacity retention behavior of LMNOF. Surface and bulk based measurements indicate an increase in disorder and gradual removal of F and Li. All of these processes mimic an aging process similar to cycling. This a priori formed interface allows for increased stability with respect to retention of capacity and oxygen loss. Abstract : Cathode/electrolyte interface stabilization in disordered rock salts was achieved by a priori modification of the surface layer by electrolyte pre‐treatment. The exposure to electrolyte removes an amorphous layer on the surface exposing fresh crystalline facets for Li (de)intercalation. It also acts as a trigger to reduce cation short range order and form a more permeable 0‐TM network. The resulting modified material indicates a 10 % improvement in capacity retention.