The poor performance of lithium-ion batteries in extreme temperatures is hindering their wider adoption in the energy sector. A fundamental challenge in battery thermal management systems (BTMSs) is that hot and cold environments pose opposite requirements: thermal transmission at high temperature for battery cooling, and thermal isolation at low temperature to retain the batteries’ internally generated heat, leading to an inevitable compromise of either hot or cold performances. Here, we demonstrate a thermal regulator that adjusts its thermal conductance as a function of the temperature, just as desired for the BTMS. Without any external logic control, this thermal regulator increases battery capacity by a factor of 3 at an ambient temperature (T_ambient) of −20 °C in comparison to a baseline BTMS that is always thermally conducting, while also limiting the battery temperature rise to 5 °C in a very hot environment (T_ambient = 45 °C) to ensure safety. The result expands the usability of lithium-ion batteries in extreme environments and opens up new applications of thermally functional devices.

锂离子电池在极端温度下的不良性能阻碍了其在能源领域的广泛采用。电池热管理系统（BTMS）的一个基本挑战是，冷热环境提出了相反的要求：高温下的热传递用于电池冷却，低温下的热隔离以保留电池内部产生的热量，导致不可避免的折衷不论是热还是冷的表演。在这里，我们演示了一种热调节器，它可以根据BTMS的要求根据温度调节其热导率。在没有任何外部逻辑控制的情况下，该热调节器在环境温度（T_环境）相对于始终保持导热的基准BTMS而言为-20°C），同时还在非常热的环境（T_环境 = 45°C）中将电池温度上升限制在5°C以确保安全。结果扩展了锂离子电池在极端环境下的可用性，并开创了热功能设备的新应用。