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SJTU Refrigeration and Cryogenics Institute Published Results in Advanced Materials

October 22, 2019      Author: SJTU Institute of Refrigeration and Cryogenics

Recently, SJTU researchers published new research results in Advanced Materials, the top journal of material science. The interdisciplinary cooperation team consists of Professor Wang Ruzhu and Associate Professor Li Tingxian from Innovative Team for Energy, Water and Air of Institute of Refrigeration and Cryogenic Engineering, Professor Deng Tao from School of Materials Science and Engineering, and Professor Bao Hua from the University of Michigan-Shanghai Jiao Tong University Joint Institute. The paper, titled "High-Performance Thermally Conductive Phase Change Composites by Large-Size Oriented Graphite Sheets for Scalable Thermal Energy Harvesting", proposed new method of highly thermally conductive phase‐change composites by construction of large aligned graphite sheets.

The material design applied low-cost high-output expanded graphite as thermal enhancement additive to achieve superior thermal conductivity than high-cost graphene. This method is expected to accelerate business application of phase-change materials in large‐scale thermal energy storage and thermal management of electronics. The first authors of this paper are Ph.D. student Wu Si and Associate Professor Li Tingxian of SJTU CRI. The corresponding authors are Li Tingxian, Professor Wang Ruzhu and Professor Deng Tao.

 

Abstract

Efficient thermal energy harvesting using phase‐change materials (PCMs) has great potential for cost‐effective thermal management and energy storage applications. However, the low thermal conductivity of PCMs (KPCM) is a long‐standing bottleneck for high‐power‐density energy harvesting. Although PCM‐based nanocomposites with an enhanced thermal conductivity can address this issue, achieving a higher K (>10 W m-1 K-1) at filler loadings below 50 wt% remains challenging. A strategy for synthesizing highly thermally conductive phase‐change composites (PCCs) by compression‐induced construction of large aligned graphite sheets inside PCCs is demonstrated. The millimeter‐sized graphite sheet consists of lateral van‐der‐Waals‐bonded and oriented graphite nanoplatelets at the micro/nanoscale, which together with a thin PCM layer between the sheets synergistically enhance KPCM in the range of 4.4-35.0 W m-1 K-1 at graphite loadings below 40.0 wt%. The resulting PCCs also demonstrate homogeneity, no leakage, and superior phase change behavior, which can be easily engineered into devices for efficient thermal energy harvesting by coordinating the sheet orientation with the thermal transport direction. This method offers a promising route to high‐power‐density and low‐cost applications of PCMs in large‐scale thermal energy storage, thermal management of electronics, etc.

 

Paper Link: https://onlinelibrary.wiley.com/doi/10.1002/adma.201905099

 

Translated by Zhang Qianqian

Reviewed by Wang Bingyu