Graphene Aerogel‐Supported Phase‐Change Material for Pyroelectric Energy Harvesting: Structural Modification and Form Stability Analysis

Abstract

3D porous graphene aerogel (GA) has a capability to infiltrate plenty of phase‐change materials (PCM) into the internal pore. Since carbon‐based materials can offer excellent solar light absorption and conversion of thermal energy, they are widely used as container‐like supporting materials. In general, the GA shows a volume shrinkage problem due to the capillary force during the infiltration process, thus causing a loss in pore volume, that is, PCM weight loss. The PCM amount is proportional to both the absorbed and released thermal energies. Herein, cysteamine is introduced to bind GA. The PCM composite can reduce the volume shrinkage and have an excellent form stability even under the external force. Two kinds of PCMs are connected to a pyroelectric electrode to generate electrical energy. In addition, finite‐element method estimates the temperature profile and electrical peaks to confirm experimental results.

Preparation and properties of phase-change materials with enhanced radial thermal conductivities based on anisotropic graphene aerogels

“…This occurred because the graphene aerogel increased the internal thermal conductivity of the paraffin wax, accelerated the heat transfer rate from the outside to the inside, and reduced the overheating phenomenon, thereby reducing the overall melting temperature. 9,17 The same mechanism was responsible for the change in the solidification process. Increasing the thermal conductivity reduces the undercooling phenomenon, thereby increasing the freezing point temperature.…”

Modified Supporting Materials to Fabricate Form Stable Phase Change Material with High Thermal Energy Storage

“…The capacity for thermal energy storage (TES) is related to the mass of pure PCM. It is necessary to prevent volume shrinkage in the fabrication process [ 61 ]. The oxidation of the graphene aerogel can generate additional functional groups for chemical reactions with cysteamine using the high temperature vapor method [ 62 ].…”

Energy harvesting and electricity production through dissolved carbon dioxide by connecting two form-stable phase change materials

“…30,31 Considering that carbon based materials can absorb sunlight efficiently, a graphene aerogel supported PCM composite has also been utilized for constructing a solar-to-electrical power generator and produced a stable and continuous electrical energy output during the light-on/-off process. 32,33 In addition, two types of PCM composites with different phase transition temperatures have been connected onto each side of a power generator to generate electrical energy during the heating and cooling processes. 34,35 The working condition of this model is close to that for practical applications, which makes it possible to generate electrical energy merely with the change in external temperatures.…”