Organocatalytic Lithium Chloride Oxidation by Covalent Organic Frameworks for Rechargeable Lithium-Chlorine Batteries

Rechargeable Li-Cl2 battery is a promising high energy density battery system. However, reasonable cycle life could only be achieved under low specific capacities due to the sluggish oxidation of LiCl to Cl2. Herein, we propose an amine-functionalized covalent organic framework (COF) with catalytic activity, namely COF-NH2, that significantly decreases the oxidation barrier of LiCl and accelerates the oxidation kinetics of LiCl in Li-Cl2 cell. The resulting Li-Cl2 cell using COF-NH2 (Li-Cl2@COF-NH2) simultaneously exhibits low overpotential, ultrahigh discharge capacity up to 3500 mAh/g and a promoted utilization ratio of deposited LiCl at the first cycle (UR-LiCl) of 81.4 %, which is one of the highest reported values to date. Furthermore, the Li-Cl2@COF-NH2 cell could be stably cycled for over 200 cycles when operating at a capacity of 2000 mAh/g at -20 degrees C with a Coulombic efficiency (CE) of approximate to 100 % and a discharge plateau of 3.5 V. Our superior Li-Cl2 batteries enabled by organocatalyst enlighten an arena towards high-energy storage applications. An amine-functionalized COF with catalytic activity significantly decreases oxidation barrier and accelerates oxidation kinetics of LiCl in rechargeable Li-Cl2 battery. The resulting Li-Cl2 cell using COF-NH2 exhibits low overpotential and ultrahigh discharge capacity up to 3500 mAh/g, which can be stably cycled at -20 degrees C with a Coulombic efficiency of approximate to 100 %.image