Solid-solution reaction suppresses the Jahn–Teller effect of potassium manganese hexacyanoferrate in potassium-ion batteries. Issue 36 (2nd September 2022)

• Record Type: Journal Article
• Authors: Liu, Bingqiu; Zhang, Qi; Ali, Usman; Li, Yiqian; Hao, Yuehan; Zhang, Lingyu; Su, Zhongmin; Li, Lu; Wang, Chungang
• Is Part Of: Chemical science. Volume 13:Issue 36(2022)
• Page Start: 10846
• Page End: 10855
• Publication Date: 2022-09-02
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d2sc03824b
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : The hollow KMnHCF nanospheres that are organized by numerous ultrasmall KMnHCF nanocube subunits (9 nm) replace the traditional phase transition of KMnHCF by a solid-solution reaction, which effectively suppress the Jahn–Teller effect. Abstract : Potassium manganese hexacyanoferrate (KMnHCF) suffers from poor cycling stability in potassium-ion batteries due to the Jahn–Teller effect, and experiences destabilizing asymmetric expansions and contractions during cycling. Herein, hollow nanospheres consisting of ultrasmall KMnHCF nanocube subunits (KMnHCF-S) are developed by a facile strategy. In situ XRD analysis demonstrates that the traditional phase transition for KMnHCF is replaced by a single-phase solid-solution reaction for KMnHCF-S, which effectively suppresses the Jahn–Teller effect. From DFT calculations, it was found that the calculated reaction energy for K + extraction in the solid-solution reaction is much lower than that in the phase transition, indicating easier K + extraction during the solid-solution reaction. KMnHCF-S delivers high capacity, outstanding rate capability, and superior cycling performance. Impressively, the K-ion full cell composed of the KMnHCF-S cathode and graphite anode also displays excellent cycling stability. The solid-solution reaction not only suppresses the Jahn–Teller effect of KMnHCF-S but also provides a strategy to enhance the electrochemical performance of other electrodes which undergo phase transitions.