Boosting the Potassium Storage Performance of Alloy‐Based Anode Materials via Electrolyte Salt Chemistry. Issue 15 (12th February 2018)

• Record Type: Journal Article
• Authors: Zhang, Qing; Mao, Jianfeng; Pang, Wei Kong; Zheng, Tian; Sencadas, Vitor; Chen, Yuanzhen; Liu, Yajie; Guo, Zaiping
• Is Part Of: Advanced energy materials. Volume 8:Issue 15(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-02-12
• Subjects: alloy‐based anodes -- electrolyte salts -- potassium‐ion batteries -- SEI; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201703288
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: Potassium‐ion batteries (PIBs) are promising energy storage systems because of the abundance and low cost of potassium. The formidable challenge is to develop suitable electrode materials and electrolytes for accommodating the relatively large size and high activity of potassium. Herein, Bi‐based materials are reported as novel anodes for PIBs. Nanostructural design and proper selection of the electrolyte salt have been used to achieve excellent cycling performance. It is found that the potassiation of Bi undergoes a solid‐solution reaction, followed by two typical two‐phase reactions, corresponding to Bi ↔ Bi(K) and Bi(K) ↔ K5 Bi4 ↔ K3 Bi, respectively. By choosing potassium bis(fluorosulfonyl)imide (KFSI) to replace potassium hexafluorophosphate (KPF6 ) in carbonate electrolyte, a more stable solid electrolyte interphase layer is achieved and results in notably enhanced electrochemical performance. More importantly, the KFSI salt is very versatile and can significantly promote the electrochemical performance of other alloy‐based anode materials, such as Sn and Sb. Abstract : Bismuth stores potassium electrochemically via a solid‐solution reaction, followed by two typical two‐phase reactions, corresponding to Bi↔ Bi(K) and Bi(K) ↔ K5 Bi4 ↔ K3 Bi, respectively. Moreover, a more uniform, stable, conductive, and robust solid electrolyte interphase is achieved by replacing potassium hexafluorophosphate with potassium bis(fluorosulfonyl)imide (KFSI) and hence results in better cycling performance. The KFSI salt is also effective in other alloy‐based anode materials, such as Sn and Sb.