A Microcapsule‐Assistant Self‐Healing Magnesium Battery Cathodes

Self‐healing secondary batteries have attracted great attention for constructing stable energy‐storage systems. Herein, a novel self‐healing rechargeable magnesium battery cathode is developed using self‐healing microcapsules in a vanadium pentoxide microflower‐based cathode. The microcapsules are prepared through a microfluidic approach. The core of the microcapsule contains a conductive hydrogel and carbon nanospheres, and the shell composes of a UV‐curved polymer. When the self‐healing Mg battery cathode cracks, the microcapsules break and release the core into the cracks, rebuilding the pathways for the electron transport and enabling a stable electrochemical performance. The presented cathode displays a good capacity of 105 mAh g−1 after 500 cycles at 100 mA g−1 and it delivers a stable capacity of 98.3 mAh g−1 after long‐term cycling 1000 times at 200 mA g−1. A recoverable rate‐performance and a good temperature tolerance are also achieved. It is expected that the general preparation approach of the self‐healing microcapsules and the long‐term stable Mg battery will find broad applications for developing many emerging energy‐storage systems.