Self-healing polymer electrolyte for long-life and recyclable lithium-metal batteries

Nowadays, the complex application environment requires lithium batteries to be self-healing to cope with the inevitable volume changes and breakage during use. However, only a small part of self-healing materials has been applied in lithium batteries because the introduction of self-healing components will affect the electrochemical performance. Developing a self-healing and recyclable electrolyte to pursue sustainable and long-life lithium batteries is still a great challenge. Herein, a self-healing and recyclable electrolyte has been prepared with a rigid and flexible epoxy resin as a backbone and disulfide bonds as reversible cross-linking points. The epoxy resin imparts superior mechanical abilities (tensile strength >20 MPa) to the electrolytes, while the disulfide bonds provide excellent self-healing capabilities (healing efficiency >95%). Meanwhile, the ionic conductivity (25 °C) of the rigid-flexible self-healing polymer electrolytes (RFSPEs) is as high as 10−3 S/cm, and the multiple healed RFSPE has no changes in the ionic conductivity. In addition, RFSPE has an inhibitory effect on the growth of lithium dendrites, which can cycle stably for up to 1800 h at 1 mAh/cm2. The Li/LiFePO4 cell also exhibits good cycling stability and superior rate performance.