Cationic metal–organic framework derived ruthenium–copper nano-alloys in porous carbon to catalytically boost the cycle life of Li–CO₂batteries

Abstract

Rechargeable Li-CO₂ batteries are an innovative energy storage technology with broad application prospects owing to their superb energy density and ability to capture the greenhouse gas CO₂. However, they are still suffering from severe challenges in the formation and decomposition of electrochemically sluggish Li₂CO₃ discharge products, resulting in poor battery performance. Development of an efficient cathodic electrocatalyst has the potential to address these issues by catalytically boosting the conversion of Li₂CO₃. Herein, we have designed a Ru-Cu nanoalloy decorated porous carbon (Ru-Cu@NPC) material derived from an anion-exchanged cationic MOF, and it can serve as an efficient cathode electrocatalyst for Li-CO₂ batteries. Benefitting from the uniform distribution of ultrafine Ru-Cu nanoalloys with high catalytic performance, Ru-Cu@NPC displays excellent CO₂ reduction and evolution activities. Impressively, the Li-CO₂ battery with the Ru-Cu@NPC catalyst exhibits a remarkably low potential gap of 0.93 V at 100 mA g^-1 and a stable discharge/charge cycling performance of more than 400 cycles at a high current density of 400 mA g^-1 within a limiting capacity of 1000 mA h g^-1. The study provides an opportunity for the research of cationic MOF derived bimetallic catalysts in the Li-CO₂ battery field.