Efficient thermal management is crucial for ensuring the safety and performance of lithium-ion batteries powering electric vehicles. Here, we develop a passive battery thermal management system with thermally enhanced water adsorbents by evenly loading MIL-101(Cr) particles onto a copper foam. MIL-101(Cr) particles can absorb water from the ambient and release water at an elevated temperature to dissipate heat, while the copper foam acts as a thermal conductive network to transfer the heat among the particles. The cooling performance of the system is tested under various battery working conditions. Results show that the thermal conductivity of the composite water adsorbent is increased to 1.9 W m−1 K−1, nearly 10 times of the pure MIL-101(Cr). Compared with natural cooling, air cooling and solid–liquid phase change material cooling, the proposed passive cooling method reduces the battery temperature by 7.5, 2.6, and 2.1 °C, respectively, at 3 C discharge. Additionally, the battery temperature and the temperature difference are confined below 37.6 and 1.5 °C in the dynamic discharge–charge cycling test. All these encouraging results indicate that the developed passive thermal management system achieves high cooling capability, good temperature uniformity, and zero energy consumption, which possesses a broad application prospect in electric vehicles. © 2022 Elsevier Ltd