A high-capacity Sn metal anode for aqueous acidic batteries

Aqueous acidic batteries are a good choice to respond to battery diversity, delivering safety, cost, environmental friendliness, and high-power necessary for renewable energy storage. However, the practical adoption is greatly challenged by low voltage and energy density due to the inadequate metal anode materials. Here, we report an interfacial regulated Sn metal anode as the solution of the last piece of the puzzle. The ease of recycling, low potential, fast redox kinetics, and high capacity of Sn perfectly fit the battery system, and the Sn metal shedding critical issue is successfully suppressed by promoting uniform deposition for added interaction from alloying. Consequently, this reversible Sn anode with 442 mAh g−1 matches well to different types of cathodes. The as-assembled acidic batteries also demonstrate sufficient output voltage (up to 1.7 V), energy density (up to 312 Wh kg−1 based on both electrodes), kinetics (up to 24 C), and stability (up to 2,400 cycles).