Enabling unidirectional thermal conduction of wood-supported phase change material for photo-to-thermal energy conversion and heat regulation. (October 2022)

• Record Type: Journal Article
• Authors: Shi, Xuetong; Meng, Yang; Bi, Ran; Wan, Zhangmin; Zhu, Ya; Rojas, Orlando J.
• Is Part Of: Composites. Number 245(2022)
• Publication Date: 2022-10
• Subjects: Wood -- Phase change material -- Boron nitride -- Solar energy conversion -- Thermal energy storage -- Layer-by-layer assembly; Composite materials -- Periodicals; Materials science -- Periodicals; Composite materials; Periodicals; Electronic journals; 620.118
• DOI: 10.1016/j.compositesb.2022.110231
• Languages: English
• ISSNs: 1359-8368

Abstract

Abstract: Phase change materials (PCMs) enable passive thermal management by minimizing energy waste. However, a limitation of organic PCMs is their low thermal conductivity, which leads to uneven phase transitions. Herein, we introduce a composite following a green and simple synthesis strategy that uses wood's fiber anisotropy and microporosity to support an organic PCM (polyethylene glycol, PEG). We first incorporate exfoliated boron nitride (BN) and polyethylenimine (PEI) in a layer-by-layer (LbL) assembly followed by capping with conductive polypyrrole. This modification of the wood framework endows non-leaking filling with PCM and simultaneous light absorption and thermal conduction. The loaded BN provides enhanced thermal conductivity, 4.4 and 26 times higher compared to neat PEG and delignified wood. As a result, the multicomponent system is effective for solar-to-thermal energy conversion with a latent heat of melting of up to ∼160J/g (∼78% PEG encapsulation). Moreover, the modified wood composite shows thermal durability and stability for at least 50 heating and cooling cycles. Overall, we take advantage of unidirectional heat transport for light conversion and storage and demonstrate the operation principle using a proof-of-concept prototype system. Graphical abstract: Image 1 Highlights: Wood is modified layer-by-layer to enable heat transport. Wood thermal conductivity is enhanced by up to 26-fold. Polymer modification leads to light adsorption and photothermal energy conversion. A 78% thermal encapsulation efficiency is determined. We show excellent thermal durability and T regulation.