Thermally conductive phase change electrodes for in situ thermal management of lithium-ion batteries

Abstract

With the implementation of diverse application scenarios, the safety issue mainly stemming from the accumulation of generated heat and the formation of internal hot spots has become a major obstacle to the development of lithium-ion batteries (LIBs). Although external thermal management strategies for LIBs have been developed to avoid the thermal runaway, they are incapable of eliminating the temperature gradient (TG) inside an individual cell due to the difference in thermal diffusion between inside and outside the cell, which in turn affects their cycling life and operational safety. In addition, the thermal resistance contribution from the electrode is larger than that from the separator inside the battery. Herein, the effective thermal management of LIBs is achieved by in situ coating thermally conductive boron nitride (BN) and phase change microcapsules on the phosphate cathode surface, promoting uniform heat distribution and absorbing excess heat production. The batteries containing the thermal management electrode exhibit superior ion transport and rate performance, especially in high-temperature environments. The in situ modified coating on the electrode surface endows the LIBs with a positive thermal management effect and a negligible increase in the internal resistance. This work provides a viable solution to the development of internal thermal management for next-generation LIBs.