Lignin stabilizes lauric-stearic acid eutectics and suppresses supercooling for efficient thermal energy storage

Fatty acid phase change materials encounter leakage issues during phase transition and limited single working temperature in practical use. Therefore, our study developed temperature-responsive phase change microcapsules by compounding lauric acid-stearic acid eutectics (LA-SA) with lignin. Alkali lignin-based AL/LA-SA capsules exhibit stable nanostructure, tunable phase transition temperature   within the range of 36–39 °C, which can be adjusted to approach human body temperature, excellent phase change performance with low supercooling, wide operating temperature range, and maintained stability over 50 cycles. Experimental and DFT calculations reveal synergistic effects between lignin’s hydrophilic and hydrophobic groups enable efficient PCM encapsulation and provide nucleation sites for supercooling suppression, offering new theoretical basis for PCM supercooling regulation. Temperature-controllable phase change capsules show broad application prospects, facilitating targeted development and efficient utilization of phase change materials.