High-Performance Li–Se Battery Enabled via a One-Piece Cathode Design

A high-performance Li–Se battery is demonstrated by adopting a novel Se cathode design. The Se cathode is a one-piece body combined with a Se deposited current collector and a solid polymer electrolyte (SPE). In the preparation of the Se cathode, Se is electrodeposited on Ni-foam, and the pores are filled with SPE layers. Through this electrodeposition, the cathode is easily fabricated, and charge transports are facile. The use of the SPE layer offers a durable Se electrode, enhancing ion pathways, securing safety, and suppressing undesirable electrochemical reactions. Li–Se batteries assembled with the one-piece Se cathode and Li-metal anode, without using conductive carbon, polymer binder, and separator, exhibit ultrastable performance with a low capacity decay of 0.001% per cycle at 1 C over 3000 cycles. The rational design of a one-piece electrode may hold great promise for the future development of energy storage devices with facile fabrication process and long-term stability.