Water Harvesting MOF Enables Stable Cycling of Nickel-Rich Batteries

Nickel (Ni)-rich cathode materials use a high abundance of Ni instead of Cobalt (Co) while increasing battery voltage, making them the representative materials for developing high-energy-density batteries. However, Ni-rich batteries are prone to Ni leaching and performance deterioration; stable cycling thus requires strict control of the H2O/HF content in the electrolyte. Here, the use of an emerging H2O capture metal-organic framework (MOF) is reported to realize stable cycling of Ni-rich batteries with H2O-containing electrolytes. The MOF-801 separator enables NCM622 and even NCM811 batteries containing electrolyte solutions with a 300 ppm H2O content to maintain 91.4% and 81% of the initial capacities after 200 cycles at 0.2 C. Moreover, MOF-801 is found to significantly suppress fragmentation of the cathode, Li-Ni intermixing, and Ni dissolution. Additionally, the MOF-801@PP based separator can largely inhibit the lithium dendrite. The results reveal the pivotal role of MOF-801 in high-energy-density batteries, inspiring in-depth exploration of MOF's indispensable application in lithium batteries.