The graphene-based aerogels with good electrical conductivity and compressibility have been reported. However, it is challenging to fabricate the graphene aerogel to have excellent mechanical stability for its application in wearable devices. Thus, inspired by macroscale arch-shaped elastic structures and the importance of crosslinking in microstructural stability, we synthesized the mechanically stable reduced graphene oxide aerogels with small elastic modulus by optimizing the reducing agent to make the aligned wrinkled microstructure in which physical crosslinking is dominant. We used L-ascorbic acid, urea, and hydrazine hydrate as reducing agents to synthesize the graphene aerogels rGO-LAA, rGO-Urea, and rGO-HH, respectively. Hydrazine hydrate was found to be best in enhancing the physical and ionic interaction among graphene nanoflakes to achieve a wavy structure with excellent fatigue resistance. Notably, the optimized rGO-HH aerogel maintained structural stability even after 1000 cycles of compression of 50% strain and decompression, showing 98.7% stress retention and 98.1% height retention. We also studied the piezoresistive properties of the rGO-HH aerogel and showed that the rGO-HH-based pressure sensor exhibited excellent sensitivity (~5.7 kPa −1 ) with good repeatability. Hence, a super-compressible and mechanically stable piezoresistive material for wearable functional devices was demonstrated by controlling the microstructure and surface chemistry of the reduced graphene oxide aerogel.

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Ammonia-based adsorption heat pumps (AAHPs) are receiving significant attention due to effective low-grade thermal energy usability, cost-effectiveness, and ecofriendliness. For AAHPs to be widely utilized, it is essential to develop adsorbent materials that meet all of the characteristics required by AAHPs, which has been very challenging. Although metal halides (MHs) have excellent ammonia adsorption performance, their practical application to AAHPs has been limited due to their conformational instability during the ammonia adsorption−desorption process. Here, the MHimpregnated graphene aerogel (GA-NaBr) is studied from the perspective of AAHPs. Due to the pore structure formed by strong and flexible graphene networks and the high NH 3 affinity of the scaffolded NaBr, the composite addressed the MHs' issues, showing much-improved adsorption rate and stability compared to pure NaBr, while maintaining equivalent adsorption capacity. With its structural stability and impressive adsorption performance, GA-NaBr could be a breakthrough adsorption structure in the field of AAHPs.