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

Rechargeable Li–CO 2 batteries have attracted extensive attentions since their excellent abilities of absorbing CO 2 and delivering super-high energy density. Recently, many effective catalysts have been developed to improve the performance of Li–CO 2 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–CO 2 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–CO 2 battery. The LE-Li/TPE based Li–CO 2 flexible cell also shows superior performance even at different bending angles. • We constructed LE-Li by spontaneous reaction between Li metal and ethylenediamine. • LE-Li cross-linked with tetraglyme to build polymer electrolyte (TPE) in battery. • Synergy between LE-Li and TPE effectively improved performance of Li–CO 2 battery.