In this study, Nypa fruticans shell-derived cellulose was successfully produced, and the hydrothermal method was employed to generate ZnO@C (ZOC) composites, which were then subjected to calcination in N2 gas at a temperature of 600 °C for varying durations. X-ray diffraction and thermogravimetric analyses demonstrated that the annealing duration had a substantial impact on the quantities of C and ZnO in the ZOC composites. The scanning electron microscope images indicated the presence of ZnO nanoparticles on the surface of the C phase and revealed a similar morphology among the ZOC composites. ZOC anodes exhibited excellent electrochemical properties when used in lithium-ion batteries (LIBs), making them promising alternatives to graphite as LIB anode materials. As an illustration, the ZOC_2h electrode delivered a reversible capacity of 500 mAh g−1 after 100 cycles at a current density of 0.1 A g−1. The excellent electrochemical performance of the ZOC electrodes may be attributed to the carbon matrix obtained from cellulose, the appropriate quantity of C and ZnO phases in the ZOC composites, and their distinctive structure.