Electrolyte‐Mediated Stabilization of High‐Capacity Micro‐Sized Antimony Anodes for Potassium‐Ion Batteries

• Published in: Advanced materials (Weinheim) Vol. 33; no. 8; pp. e2005993 - n/a
• Main Authors: Zhou, Lin, Cao, Zhen, Zhang, Jiao, Cheng, Hraoran, Liu, Gang, Park, Geon‐Tae, Cavallo, Luigi, Wang, Limin, Alshareef, Husam N., Sun, Yang‐Kook, Ming, Jun
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.02.2021
• Subjects: Alloying; alloying anode; Anions; Anodes; Antimony; Control stability; electrolyte; Electrolytes; Electronegativity; Failure mechanisms; Materials science; Potassium; potassium‐ion battery; Rechargeable batteries; solid electrolyte interface (SEI); Solid electrolytes; Solvation; solvation structure; Solvents; solid electrolyte interface (SEI); solvation structure; alloying anode; potassium-ion battery; electrolyte
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202005993

Alloying anodes exhibit very high capacity when used in potassium‐ion batteries, but their severe capacity fading hinders their practical applications. The failure mechanism has traditionally been attributed to the large volumetric change and/or their fragile solid electrolyte interphase. Herein, it is reported that an antimony (Sb) alloying anode, even in bulk form, can be stabilized readily by electrolyte engineering. The Sb anode delivers an extremely high capacity of 628 and 305 mAh g–1 at current densities of 100 and 3000 mA g–1, respectively, and remains stable for more than 200 cycles. Interestingly, there is no need to do nanostructural engineering and/or carbon modification to achieve this excellent performance. It is shown that the change in K+ solvation structure, which is tuned by electrolyte composition (i.e., anion, solvent, and concentration), is the main reason for achieving this excellent performance. Moreover, an interfacial model based on the K+‐solvent‐anion complex behavior is presented. The electronegativity of the K+‐solvent‐anion complex, which can be tuned by changing the solvent type and anion species, is used to predict and control electrode stability. The results shed new light on the failure mechanism of alloying anodes, and provide a new guideline for electrolyte design that stabilizes metal‐ion batteries using alloying anodes. A new electrolyte‐engineering approach is presented to stabilize the micro‐sized alloying anodes (e.g., Sb anode) in potassium‐ion batteries. A high capacity of 628 mAh g–1 close to the capacity limit of potassium metal is achieved. An interfacial model related to the electronegativity and stability of the K+‐solvent‐anions is presented to predict and analyze the electrolyte stability and electrode performance.