Bifunctional Liquid Metals Allow Electrical Insulating Phase Change Materials to Dual-Mode Thermal Manage the Li-Ion Batteries

Phase change materials (PCMs) are expected to achieve dual-mode thermal management for heating and cooling Li-ion batteries (LIBs) according to real-time thermal conditions, guaranteeing the reliable operation of LIBs in both cold and hot environments. Herein, we report a liquid metal (LM) modified polyethylene glycol/LM/boron nitride PCM, capable of dual-mode thermal managing the LIBs through photothermal effect and passive thermal conduction. Its geometrical conformation and thermal pathways fabricated through ice-template strategy are conformable to the LIB's structure and heat-conduction characteristic. Typically, soft and deformable LMs are modified on the boron nitride surface, serving as thermal bridges to reduce the contact thermal resistance among adjacent fillers to realize high thermal conductivity of 8.8 and 7.6 W m(-1) K-1 in the vertical and in-plane directions, respectively. In addition, LM with excellent photothermal performance provides the PCM with efficient battery heating capability if employing a controllable lighting system. As a proof-of-concept, this PCM is manifested to heat battery to an appropriate temperature range in a cold environment and lower the working temperature of the LIBs by more than 10 degrees C at high charging/discharging rate, opening opportunities for LIBs with durable working performance and evitable risk of thermal runaway.

Automated summary

This article presents a liquid metal modified phase change material that achieves dual-mode thermal management of Li-ion batteries through photothermal effect and passive thermal conduction. The PCM has high thermal conductivity and efficient battery heating capability, allowing it to heat the battery in cold environments and lower the working temperature at high charging/discharging rates. This innovation offers opportunities for reliable operation of Li-ion batteries with improved performance and reduced risk of thermal runaway.