Hierarchical Ti3C2Tx MXene/Carbon Nanotubes for Low Overpotential and Long-Life Li-CO2 Batteries.

Electrochemical carbon dioxide conversion at ambient temperature is an efficient route to synchronously provide a continuous power supply and produce useful chemicals such as carbonates. Rigid catalysts with rational morphological and structural design are used to overcome the sluggish reaction kinetics and contribute to a better cycle life in Li-CO2 batteries. In this report, a two-dimensional Ti3C2Tx MXene/carbon heterostructure assembled parallel-aligned tubular architecture was delicately synthesized through a self-sacrificial templating method and delivered an ultralow overpotential of 1.38 V at 0.2 A·g-1. The heterostructure that inherited the high catalytic performance of Ti3C2Tx MXene and the outstanding stability of carbon material promoted the adsorption of CO2 and accelerated the decomposition of lithium carbonate, which was proved by in situ and ex situ characterizations and density functional theory calculations. The tubular architecture with large surface area was demonstrated to provide a high durability for long cycle life and ensure good contacts among gas, electrolyte, and electrode.