Industrial-scale nonmetal current collectors designed to regulate heat transfer and enhance battery safety

Abstract Safety concerns have become a long-lived challenge that impedes the industrial implementation of high-energy lithium-ion batteries (LIBs). The major safety issue, known as thermal runaway, is triggered by the local thermal aggregation caused by slower heat dissipation than that of heat generation inside the battery. However, how to improve the internal heat transfer is challenged by the low thermal conductivity of metal current collectors (CCs) and the scalable manufacturing of nonmetal CC foils. Here we report a fast thermoresponsive non-metallic CC that can substitute the benchmark metal CCs, i.e., Al and Cu foils, to regulate heat transfer and considerably enhance battery safety. The non-metallic CC was fabricated using graphene (Gr) oxide through a continuous thermal pressing process to afford a dense and defect-free Gr foil of at a hundred-meter level. This Gr foil demonstrates ultra-high thermal conductivity of up to 1400.8 W m − 1 K − 1 , about one order of magnitude higher than those of Al and Cu foils. Importantly, tangible LiNi 0.8 Co 0.1 Mn 0.1 O 2 || graphite pouch cells integrated with these fast thermoresponsive foils show faster heat dissipation, eliminating the local heat concentration and circumventing the fast exothermic aluminothermic and hydrogen-evolution reactions, which are critical factors causing the thermal failure propagation of LIB packs with Al CCs. Fast thermoresponsive and light weight Gr CC enable LIBs to operate with increased output energy and survive under extremely harsh abuses.