© 2020 Defect engineering, which is a concept applied to exploit the potential of a given material fully, is also considered when designing materials for energy-related applications. In general, defect engineering focuses on the direct chemical or physical changes caused by defects through varied mechanisms. In this study, sulfur vacancies on the surface of molybdenum disulfide (MoS2) nanoflakes are created easily via hydrogen-etching and are employed to improve the composite uniformity and binding condition with tin dioxide (SnO2), which is strongly related to electrochemical performance. When the as-prepared MoS2-SnO2 is used as the anode material in a lithium-ion battery (LIB), it delivers a peak capacity of 800 mAh g−1, while retaining a capacity of 580 mAh g−1 in the 1000th cycle at a current density of 1 A g−1. The vacancy-assisted compositing method we propose is demonstrated to be an effective and controllable synthetic technology and is expected to work in an analogous way for preparing MoS2 composites with other promising oxide anode candidates (e.g., Fe3O4, CoO, or MnO) in LIB applications.