Reinforced Capacity and Cycling Stability of CoTe Nanoparticles Anchored on Ti<sub>3</sub>C<sub>2</sub> MXene for Anode Material.

Abstract

Developing high-performance anode materials is critical for lithium-ion batteries (LIBs) to meet consumers' demands. Cobalt tellurides (CoTe) exhibit promising electrochemical properties due to their higher theoretical capacity compared to commonly used graphite anodes. However, their practical application is hindered by poor electrical conductivity, agglomeration of nanoparticles, and significant volume changes during charge-discharge cycling. To overcome these challenges, CoTe nanoparticles are synthesized and anchored on Ti₃C₂ MXene (CoTe@Ti₃C₂) via a facile hydrothermal approach. The integration of CoTe nanoparticles with Ti₃C₂ nanosheets leverages their synergistic advantages: Ti₃C₂ MXene serves as a conductive substrate, improving electrical conductivity, reducing CoTe agglomeration, and accommodating volume changes, while CoTe nanoparticles prevent Ti₃C₂ nanosheet restacking. As a result, compared to the CoTe electrode, the CoTe@Ti₃C₂ anode exhibits an exceptional capacity increase, exceeding tenfold and reaching 698 mAh g^-1 after 1000 cycles at 0.1 A g^-1. Additionally, the CoTe@Ti₃C₂ anode demonstrates long-term cycling stability over 1300 cycles at 1 A g^-1. In situ synchrotron X-ray diffraction and in situ X-ray absorption spectroscopy elucidate the insights into the charge storage mechanisms. The superior electrochemical performance of CoTe@Ti₃C₂ highlights its potential as a high-performance anode material for next-generation LIBs.