N-doped Ti3C2Tx MXene sheet-coated SiOx to boost lithium storage for lithium-ion batteries

Constructing SiOx-based composite materials with fast reaction kinetics and high stability is crucial but challenging for high-performance lithium-ion batteries. Herein, we developed the N-doped Ti3C2Tx MXene ultrathin sheet (NTS)-coupled SiOx nanoparticles using a melamine-assisted ball milling and annealing procedure. The principle of melamine in exfoliating MXene was demonstrated by contrast experiments and theoretical calculations. The strong interfacial interactions between SiOx and the NTS (Si−O−Ti bond) can effectively enhance the electron transfer and ensure electrode stability. Moreover, the NTS with rich surface groups endowed the composite with a pseudocapacitive behavior, beneficial for fast lithium storage. As a result, the composite delivered a long lifespan (∼700 mA h g−1 over 800 cycles at 1.0 A g−1) and a superior rate performance (596.4 mA h g−1 at 5 A g−1). More importantly, the composite in half and full cells exhibited high areal capacity and good cycling stability at high mass loadings, revealing a promising application prospect.