The Negative-Charge Triggered "Dead Zone" Between Electrode and Current Collector Realizes Ultralong Cycle Life of Aluminum-Ion Batteries.

Typically, volume expansion of the electrodes after active ions intercalation is highly undesirable yet inevitable, which can significantly reduce the adhesion force between the electrodes and current collectors. Especially in aluminum-ion batteries (AIBs), the intercalation of large-sized AlCl 4 - 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, we have come out with an interesting concept, the "dead zone", to overcome the above challenge. By incorporating a large number of OH - and COOH - groups onto the surface of MXene film, rich negative charges 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 AlCl 4 - 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 has helped to effectively increase the battery's cycle life to as high as 50,000 times. We believe the proposed concept can be an important reference for future development of current collectors in rocking chair batteries. This article is protected by copyright. All rights reserved.