Promoting the Energy Conversion of Li-CO2/O2 Batteries via Ru-Doped HKUST with Substantial Adsorption and Excellent Catalytic Effect

Abstract

Li-CO2/O-2 batteries hold tremendous promises for energy storage and conversion systems, attributed to their high theoretical energy density and economic viability. Nevertheless, their widespread application is hindered by high overpotential and compromised cycling stability. Herein, ruthenium (Ru)-doped copper-based metal organic frameworks (HKUST) octahedral particles (Ru@HKUST) are synthesized as the cathode catalyst for Li-CO2/O-2 batteries. The Ru@HKUST matrix rich in free channels provides unimpeded gas permeation and substantial adsorption spaces for CO2/O-2. A synergistic interaction between HKUST and Ru significantly enhances the kinetic conversion of Li2CO3 upon cycles, thereby markedly boosting the capacity and extending the cycle life of Li-CO2/O-2 batteries. A high discharge capacity of 19 437 mAh g(-1) is achieved at 2 V cutoff voltage in the Li-CO2/O-2 cell with Ru@HKUST under a constant current density of 200 mA g(-1). The cells exhibit a superior catalytic efficiency with reduced charge plateaus of 4.1 V for over 100 cycles at a fixed capacity of 1000 mAh g(-1), demonstrating excellent electrochemical properties and paving the way for advanced battery technology.