Constructing SiO x -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 Ti 3 C 2 T x MXene ultrathin sheet (NTS)-coupled SiO x 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 SiO x 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.