A Thermally Chargeable Supercapacitor based on the g‐C3N4‐Doped PAMPS/PAA Hydrogel Solid Electrolyte and 2D MOF@Ti3C2Tx MXene Heterostructure Composite Electrode

• Published in: Advanced materials interfaces Vol. 10; no. 17
• Main Authors: Du, Zhijian, Liu, Weijia, Liu, Jinhai, Chu, Zhengyu, Qu, Fengyu, Li, La, Shen, Guozhen
• Format: Journal Article
• Language: English
• Published: Weinheim John Wiley & Sons, Inc 01.06.2023; Wiley-VCH
• Subjects: 2D MOF; Carbon nitride; Electrodes; Electrolytes; Energy harvesting; Heterojunctions; Heterostructures; Human motion; hydrogel electrode; Hydrogels; Hydrogen bonds; MXenes; Pore size; Pressure sensors; Protons; Seebeck effect; Solid electrolytes; Soret effect; Supercapacitors; Temperature gradients; Thermal energy; thermal‐chargeable supercapacitor; Ti 3C 2T x MXene
• ISSN: 2196-7350; 2196-7350
• DOI: 10.1002/admi.202300266

With the development of individual wearable electronics, the requirements of self‐energy harvest devices from human skin or motion have increased. A thermal harvest device that receives thermal energy naturally existed in human skin is more attractive than a mechanical energy harvester that needs human motion or walking. Herein, a thermal‐chargeable supercapacitor (TCSC) is proposed, which can convert thermal energy into electrical energy and then store the energy only by occurring the temperature difference between the two ends of the TCSC. The all‐solid‐state g‐C3N4‐modified hydrogel electrolyte in the TCSC provides more free protons and energy for proton migration by the electrostatic interaction and hydrogen bond interaction between g‐C3N4 and the acid group. The 2D MOF@Ti3C2Tx MXene heterojunction electrodes with the advantages of large pore size, adjustable and abundant REDOX sites of MOFs, and high conductivity of Ti3C2Tx MXene also ensure the high performance of the TCSC. As a result, the assembled TCSC exhibits excellent ionic thermal‐voltage (55.68 mV), Seebeck coefficient (18.56 mV K−1), and energy exchange efficiency (3.4%) upon a temperature difference of 3 K, and successfully drives the pressure sensor work. A wearable thermal‐chargeable supercapacitor (TCSC) that consists of Ti3C2Tx MXene‐based composite as flexible electrode and g‐C3N4‐doped acidic hydrogel as solid electrolyte is fabricated, which exhibits excellent ionic thermal‐voltage (55.68 mV), Seebeck coefficient (18.56 mV K‐1) and energy exchange efficiency (3.4%) upon dT = 3 K. An integrated pressure sensing system powered by TCSC is designed to realize the real‐time monitor of human activity.