A Rechargeable Li-CO2 Battery with a Gel Polymer Electrolyte.

The utilization of CO2 in Li-CO2 batteries is attracting extensive attention. However, the poor rechargeability and low applied current density have remained the Achilles' heel of this energy device. The gel polymer electrolyte (GPE), which is composed of a polymer matrix filled with tetraglyme-based liquid electrolyte, was used to fabricate a rechargeable Li-CO2 battery with a carbon nanotube-based gas electrode. The discharge product of Li2 CO3 formed in the GPE-based Li-CO2 battery exhibits a particle-shaped morphology with poor crystallinity, which is different from the contiguous polymer-like and crystalline discharge product in conventional Li-CO2 battery using a liquid electrolyte. Accordingly, the GPE-based battery shows much improved electrochemical performance. The achieved cycle life (60 cycles) and rate capability (maximum applied current density of 500 mA g-1 ) are much higher than most of previous reports, which points a new way to develop high-performance Li-CO2 batteries.