Protecting Li-metal anode with ethylenediamine-based layer and in-situ formed gel polymer electrolyte to construct the high-performance Li–CO2 battery

Abstract

Rechargeable Li–CO2 batteries have attracted extensive attentions since their excellent abilities of absorbing CO2 and delivering super-high energy density. Recently, many effective catalysts have been developed to improve the performance of Li–CO2 batteries, which nevertheless is still inhibited by problems derived from Li anodes and liquid electrolyte, such as Li dendrites and electrolyte leakage. In this work, we construct Li-ethylenediamine (LE) layer on Li (LE-Li) and use it to further react with tetraglyme in battery to obtain tetraglyme-based polymer electrolyte (TPE). The uniform LE layer coupled with in-situ formed TPE can not only restrain dendrite generation, Li-induced side reaction and corresponding passivation/pulverization, but also reduce interfacial impedance and enable battery work normally at bending condition. Therefore, the LE-Li electrode presents the more stable electrochemical property than the pure Li anode in symmetric battery. Additionally, the Li–CO2 battery using LE-Li/TPE displays high discharge capacity of 22873 mAh g−1 and good rate capability under full discharge/charge condition. When operated at cut-off capacity, this cell can steadily run for 104 cycles with a small overpotential of <1.9 V, which is better than bare Li/liquid electrolyte-based Li–CO2 battery. The LE-Li/TPE based Li–CO2 flexible cell also shows superior performance even at different bending angles.