RECHARGEABLE LI//BR BATTERY: A PROMISING PLATFORM FOR POST LITHIUM ION BATTERIES

摘要

Energy storage systems with higher energy density and good electrochemical performance are urgently demanded in new energy industry for electric vehicles, which is one promising way to increase energy efficiency, reduce carbon emission and protect our environment. Lithium ion batteries including some systems such as Li//S, Li//air (or oxygen) batteries are encountered with the bottleneck. Here another rechargeable lithium battery, Li//Br, is reported by using aqueous bromide/tribromide redox pair as positive electrode and a coated lithium metal as negative electrode. The positive Br_2 electrode shows fast redox kinetic and good stability. This battery presents excellent electrochemical performance with an average discharge voltage up to 3.96 V at 1.7 mA cm~(-2), an energy density of 1220 Wh kg~(-1), a power density of 29.7 mW cm~(-2) at current density of 12.8 mA cm~(-2), and long cycling life. There is no evident voltage decrease after 100 cycles at 35% DOD. It would become a good platform between lithium ion batteries and Li//air batteries since the former shows lower energy density and the latter has quite some challenging problems to solve prior to practical application. This finding will present another promising choice for electrochemical energy storage systems. This work was supported by NSFC (21073046 and 21374021) and STCSM (12JC1401200).