Unlocking the potential of liquid crystals as phase change materials for thermal energy storage
Rahul Karyappa, Jiayao Cheng, Chanda Ho, Suxi Wang, Warinton Thitsartarn, Junhua Kong, Dan Kai, Beng Hoon Tan, Pei Wang, Zhengyao Qu, Xian Jun Loh, Jianwei Xu, Qiang Zhu
Abstract
This review paper examines the innovative use of liquid crystals (LCs) as phase change materials in thermal energy storage systems. With the rising demand for efficient energy storage, LCs offer unique opportunities owing to their tunable phase transitions, high latent heat, and favorable thermal conductivity. This paper covers various types of LCs, such as nematic, smectic, and cholesteric phases, and their roles in enhancing thermal energy storage. It discusses the mechanisms of LC phase transitions and their impact on energy storage efficiency. Strategies to improve the thermal conductivities of LCs and LC polymers have also been explored. One method involves embedding LC units within the molecular structure to promote orderly arrangement, facilitate heat flow, and reduce phonon scattering. Aligning polymer chains through external fields or mechanical processes significantly improves intrinsic thermal conductivity. The inclusion of thermally conductive fillers and optimization of filler-matrix interactions further boost thermal performance. Challenges related to the scalability, cost-effectiveness, and long-term stability of LC-based phase change materials are addressed, along with future research directions. This review synthesizes the current knowledge and identifies gaps in the literature, providing a valuable resource for researchers and engineers to develop advanced thermal energy storage technologies, contributing to sustainable energy solutions.