In-situ electrochemical activation accelerates the magnesium-ion storage

Rechargeable magnesium batteries (RMBs) have emerged as a highly promising post-lithium battery systems owing to their high safety, the abundant Magnesium (Mg) resources, and superior energy density. Nevertheless, the sluggish kinetics has severely limited the performance of RMBs. Here, we propose an in-situ electrochemical activation strategy for improving the Mg-ion storage kinetics. We reveal that the activation strategy can effectively optimize surface composition of cathode that favors Mg-ion transport. Cooperating with lattice modifications, the CuSe | |Mg batteries exhibit a specific capacity around 160 mAh/g after 400 cycles with a capacity retention of over 91% at the specific current of 400 mA/g. Of significant note is the slight decay in specific capacity from 205 to 141 mAh/g has been observed with an increase in specific current from 20 to 1000 mA/g. This strategy provides insights into accelerating Mg-ion storage kinetics, achieving a promising performance of RMBs especially at high specific current.