Enhancement of Structural Stability of Graphene Aerogel for Thermal Energy Harvesting

Abstract

In this work, a modified graphene aerogel with high mechanical properties is synthesized. Structural stability is a general problem of graphene aerogels. Graphene oxide (GO) is employed to provide functional groups on the surface by the oxidation of potassium permanganate (KMnO4). The internal structure of the graphene aerogel is successfully cross-linked using a cysteamine vapor method. The cross-linked graphene/cysteamine aerogel (GCA) is strong enough to reduce volume shrinkage during the phase change material (PCM) infiltration process. Furthermore, the GCA can hold some additional pure PCM into the internal space without any structural damage. To consider the application in external environments, we adopt solar light, and the GCA-supported PCM composites can readily absorb solar light with various intensities to transfer the thermal energy. PCM composite constructed PN junction thermoelectric power generator (PN TEG) can produce electrical energy according to the light-on/-off process, where the thermoelectric energy harvesting efficiencies are 67.92 and 41.72%, respectively. To demonstrate the experimental results, the finite numerical calculation method is utilized.

Characterization of Phase Change Materials Fabricated with Cross-Linked Graphene Aerogels

“…After removing the excess KMnO 4 by adding citric acid, the oxidized GO was purified by centrifugation and freeze-drying process. The oxidized GO aerogel was obtained by mixing with GNP, evaporating solvent, and utilizing the cysteamine vapor method to cause a chemical reaction with GO functional groups [ 45 , 46 ]. As a result, cross-linked graphene aerogel was synthesized successfully.…”

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

“…The oxidized GO has a large number of functional groups. [ 50 ] The oxidized GO power was obtained by removing the excess KMnO 4 and freeze‐drying method. The GNP was embedded into the oxidized GO solution, and the oxidized GO/GNP aerogel was prepared.…”

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

“…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 ]. Thus, a cross-linked graphene aerogel (GCA) was utilized as an advanced supporting material and dipped into the melted PEG for 6 h with a vacuuming process.…”