Electron Transport and Ion Diffusion in Hydrogen-Bonded Interlayer Cross-Linked Graphene/MXene for Wearable Micro-Sensors

2D graphene and MXene have attracted much attention in the field of energy storage devices and wearable sensors due to their excellent electrical conductivity and mechanical properties. However, the capacitance of their composites is limited by low electron transport and sluggish ion diffusion due to the lack of electron transport and ion diffusion channels between stacked interlayers. Herein, this work reports the possibility of using disodium terephthalate as an auxiliary conductive bridge to cross-link the interlayer interaction between graphene and MXene from theoretical analysis and experimental verification. The cross-linker with a dicarboxyl group and a conjugated structure forms hydrogen bonds with the hydroxyl groups on the surface of graphene and MXene to provide a pathway for interlayer electron transfer, while inhibiting interlayer stacking and ensuring an effective ion diffusion process. To verify the actual effect of this approach, micro-sensors are assembled by the integration of micro-supercapacitors. The assembled micro-sensors demonstrate real-time monitoring of body movements and temperature signals. This work provides a feasible strategy to promote electron transport and ion diffusion in layered composites to design next-generation multifunctional micro-devices.