Polypyrrole‐boosted photothermal energy storage in MOF‐based phase change materials

Abstract Infiltrating phase change materials (PCMs) into nanoporous metal–organic frameworks (MOFs) is accepted as a cutting‐edge thermal energy storage concept. However, weak photon capture capability of pristine MOF‐based composite PCMs is a stumbling block in solar energy utilization. Towards this goal, we prepared advanced high‐performance pristine MOF‐based photothermal composite PCMs by simultaneously integrating photon absorber guest (polypyrrole [PPy]) and thermal storage guest (1‐octadecanol [ODA]) into an MOF host (Cr‐MIL‐101‐NH 2 ). The coated PPy layer on the surface of ODA@MOF not only serves as a photon harvester, but also serves as a phonon enhancer. Resultantly, ODA@MOF/PPy composite PCMs exhibit intense and broadband light absorption characteristic in the ultraviolet–visible–near‐infrared region, and higher heat transfer ability than ODA@MOF. Importantly, the photothermal conversion and storage efficiency of ODA@MOF/PPy‐6% is up to 88.3%. Additionally, our developed MOF‐based photothermal composite PCMs also exhibit long‐standing antileakage stability, energy storage stability, and photothermal conversion stability. The proposed coating strategy and in‐depth understanding mechanism are expected to facilitate the development of high‐efficiency MOF‐based photothermal composite PCMs in solar energy utilization.