Hierarchical Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> MXene/Carbon Nanotubes for Low Overpotential and Long-Life Li-CO<sub>2</sub> Batteries.

Hu, Zhe; Xie, Yaoyi; Yu, Deshuang; Liu, Qiannan; Zhou, Limin; Zhang, Kai; Li, Peng; Hu, Feng et al. · ACS Nano · 2021

basic_science · Level V

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Abstract

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-CO<sub>2</sub> batteries. In this report, a two-dimensional Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> 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<sup>-1</sup>. The heterostructure that inherited the high catalytic performance of Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> MXene and the outstanding stability of carbon material promoted the adsorption of CO<sub>2</sub> and accelerated the decomposition of lithium carbonate, which was proved by <i>in situ</i> and <i>ex situ</i> 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.