Navigating the safe operation of high-voltage cathodes: Challenges and strategies

Lithium-ion batteries play a crucial role in storing energy for renewable sources and electric vehicles, yet face challenges related to insufficient energy density. Elevating the working-voltage of cathodes is promising to boost the energy density of batteries by increasing both the output voltage and capacity of cathode, which however could compromise life cycle and safety. This review provides a comprehensive summary of essential factors governing pathways of cathode-induced thermal runaway, including electrolyte decomposition, phase transitions, and crosstalk-induced reactions. Electrode and electrolyte modifications aimed at mitigating parasitic reactions and preventing crosstalk were also discussed. The review concludes with insights into the future application of these strategies, providing a comprehensive perspective on the realization of high-energy and safe batteries.