The Negative‐Charge‐Triggered “Dead Zone” between Electrode and Current Collector Realizes Ultralong Cycle Life of Aluminum‐Ion Batteries

• Published in: Advanced materials (Weinheim) Vol. 35; no. 50; pp. e2205489 - n/a
• Main Authors: Guan, Wei, Huang, Zheng, Wang, Wei, Song, Wei‐Li, Tu, Jiguo, Luo, Yiwa, Lei, Haiping, Wang, Mingyong, Jiao, Shuqiang
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01-12-2023
• Subjects: Aluminum; aluminum‐ion batteries; Battery cycles; Collectors; current collector; dead zone; Electrodes; Intercalation; Materials science; Ti 3C 2T x films; ultralong cycle life; current collector; Ti 3C 2T x films; ultralong cycle life; aluminum-ion batteries; dead zone
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202205489

Typically, volume expansion of the electrodes after intercalation of active ions is highly undesirable yet inetvitable, and it can significantly reduce the adhesion force between the electrodes and current collectors. Especially in aluminum‐ion batteries (AIBs), the intercalation of large‐sized AlCl4− can greatly weaken this adhesion force and result in the detachment of the electrodes from the current collectors, which seems an inherent and irreconcilable problem. Here, an interesting concept, the “dead zone”, is presented to overcome the above challenge. By incorporating a large number of OH− and COOH− groups onto the surface of MXene film, a rich negative‐charge region is formed on its surface. When used as the current collector for AIBs, it shields a tiny area of the positive electrode (adjacent to the current collector side) from AlCl4− intercalation due to the repulsion force, and a tiny inert layer (dead zone) at the interface of the positive electrode is formed, preventing the electrode from falling off the current collector. This helps to effectively increase the battery's cycle life to as high as 50 000 times. It is believed that the proposed concept can be an important reference for future development of current collectors in rocking chair batteries.
A stable, lightweight, durable, and low‐cost current collector, MXene (Ti3C2Tx) film, is achieved for aluminum‐ion batteries. A large number of OH− and COOH− groups are incorporated onto the surface of the MXene film to form rich negative charges region on its surface, which shields the positive electrode material from AlCl4− intercalation in its “dead zone.”