Diethyl ether as self-healing electrolyte additive enabled long-life rechargeable aqueous zinc ion batteries

Aqueous rechargeable zinc ion batteries (ARZIBs) is considered one of the most compelling candidates for grid-scale energy storage owing to their cost effectiveness, good safety, eco-friendliness, high output voltage, and high capacity. However, their practical applications are still largely limited by the undesirable cyclability and high-rate capability. Here, we report a discovery that using a small amount (2 vol%) of diethyl ether (Et2O) as the electrolyte additive could largely improve the performance of Zn-MnO2 batteries. The addition of Et2O yielded the first cycle coulombic efficiency of 95.6% at 50 mA/g, a high capacity of 115.9 mAh/g at 5 A/g and 97.7% retention of initial capacity after 4000 cycles, demonstrating an outstanding rate capability and cycling performance among the reported Mn-based zinc ions batteries in mild electrolyte. Ex-situ characterizations revealed that appropriate amount of Et2O molecules could effectively suppress the formation of Zn dendrites on Zn anode, which is the main mechanism for cyclability improvements.