Thermoregulating phase-change composite separators with thermal runaway suppression for safe and high-performance lithium-ion batteries.

Lithium-ion batteries(LIBs)have been widely used and its safety has attracted much attention. Separators are an essential part of ensuring the safety of LIBs by both allowing ion transport and preventing direct electrical contact between the cathode and anode, Herein, a unique temperature-regulating separator that is thermally stimuli-responsive is designed. A thermosensitive composite separator was ingeniously crafted by filling hollow halloysite that followed by encapsulation with a phase change materials (PCMs) and a bio-adhesive polydopamine with a high-temperature-resistant poly (arylene ether nitriles) polymer. The enthalpy of the separator spans a broad range of 3-12 J g, enabling composite separator to effectively alleviate the internal temperature escalation in LIBs. Under harsh conditions, the heat generated within the battery triggers the melting of the encapsulated PCM. This process absorbs a substantial amount of heat, thereby preventing a significant temperature increase. Moreover, separators demonstrate superior electrochemical performance compared to commercial polyolefin separators. PCM-based separator hold promise for mitigating safety hazards associated with thermal runaway in batteries. This innovative approach offers valuable insights for the development of multifunctional separators aimed at enhancing the safety of LIBs.