Preparation of polyacrylamide/calcium alginate@Ti3C2Tx composite hydrogels with high adhesive performance for flexible supercapacitor electrolytes.

Polymer hydrogels are a promising electrolyte for flexible superconductors (FSCs) due to their excellent flexibility, ions transportations and interfacial compatibility. However, the large internal resistance will decrease the power density (PD) and energy density (ED) of FSCs. In this work, Ti 3 C 2 T x was introduced to polyacrylamide/calcium alginate (PC) hydrogel electrolyte to decrease the internal resistance (IR) and improve the interfacial adhesion. The polyacrylamide/calcium alginate@Ti 3 C 2 T x (PCT) composite hydrogels were successfully prepared by in-situ polymerization. Their mechanical property and adhesive property to various substrates were investigated, respectively, and a flexible supercapacitor was assembled with composite hydrogels as electrolyte and two self-made Ti 3 C 2 T x sheets as electrode. It was found composite hydrogels can adhere to various substrates, which make the voltage drop of FSCs from 163 mV to 78.9 mV. The FSCs show a good performance, whose specific capacitance is 1051.9 mF cm−2 with a current density of 1.07 mA cm−2, and the ED reaches 32.3 Wh kg−1 and the capacitance retention rate is as high as 96% at a high current density of 18.7 mA cm−2. Meanwhile, it can sensitively monitor human movements such as finger bending, frowning, swallowing, etc. This work is expected to be applied in the field of energy storage and sensing. [Display omitted] • Ti 3 C 2 T x was introduced to the PC hydrogel to decrease the internal resistance and improve the interfacial adhesion. • The FSC with PCT as electrolyte has high specific capacitance (1051.9 mF cm−2) and large energy density (32.3 Wh kg−1). • The PCT hydrogel shows a good performance in the field of sensing, it can sensitively monitor many human movements. [ABSTRACT FROM AUTHOR]