在“碳中和、碳达峰”的背景下，如何减少化石能源的应用，开发新能源，提高能源利用率成为世界共同关注的问题，相变材料在未来拥有广泛的应用前景。本文从掰掰乐暖手袋的加热原理出发，介绍了热冰实验，即醋酸钠过饱和溶液结晶，释放相变潜热的实验现象。本实验不仅具有化学之美，在实际生活中也具有重要意义。本实验启发读者从电池对于电能的储存与使用出发，思索利用相变潜热对热能进行储存和利用的可行性，并介绍了几个相关领域的应用案例。

In the context of global efforts toward carbon neutrality and peak carbon emissions, developing alternative energy solutions and improving energy efficiency have become critical priorities. Phase change materials(PCMs) show significant promise in addressing these challenges. This article explores the fundamental chemistry behind reusable hand warmers through the “hot ice” experiment, demonstrating how crystallization of supersaturated sodium acetate solution releases latent heat. Beyond its visual appeal, this experiment serves as an engaging introduction to thermal energy storage concepts. We draw parallels between electrical energy storage in batteries and thermal energy storage using PCMs, presenting several practical applications that highlight the potential of this technology for sustainable energy solutions.