An All-Solid-State Flexible Supercapacitor Based on MXene/MSA Ionogel and Polyaniline Electrode with Wide Temperature Range, High Stability, and High Energy Density

Abstract

In this study, an ionogel electrolyte (PAIM-X) consisting of 1-vinyl-3-methylimidazole bis (trifluoromethyl sulfonyl) imide ([VMIM][TFSI]), Polyacrylamide (PAAm), and MXene were prepared. The conductivity of PAIM-X and integral area of the voltammetric curve of the supercapacitor (PAIMSC) were improved by adding MXene. The addition of [VMIM][TFSI] enhanced the conductivity and applicable temperature of the ionogel electrolyte. At 90 °C, the conductivity of PAIM-4 can reach 36.4 mS/cm. In addition, spherical polyaniline with good electrochemical properties was synthesized and coated on graphite paper as an active substance. An all-solid-state supercapacitor was composed of PAIM-4, polyaniline electrode with 1.2 V potential window, pseudo-capacitors and high quality capacitors. The solvent 1-ethyl-3-methylimidazolium bis (trifluoromethyl sulfonyl imide) ([EMIM][TFSI]) and methanesulfonic acid (MSA) were introduced into the ionogel to promote the redox reaction of polyaniline (PANI). The mass specific capacitance of PAIMSC was 204.6 F/g and its energy density could reach 40.92 Wh/kg, which shows great potential for practical application at high temperature. The device had good rate performance and cycle performance, and its capacitance retention rate was still 91.56% after 10,000 cycles. In addition, the supercapacitor can work within the temperature range of −20 °C to 90 °C. These excellent electrochemical properties indicate that PAAm/IL/Mxene-X has broad application space and prospect.

A Flexible Supercapacitor Based on Deep Eutectic Solvent/[EMIM][TFSI] Ionogel with High Energy Density and Wide Temperature Range

“…Meanwhile, in the low-frequency region, the curve is almost parallel to the Y -axis, which also indicates that it has a low charge-transfer resistance. This is mostly owing to the injection of ionic liquids [EMIM] [TFSI] and ChCl into the gel electrolyte, which adds ionic conductivity and reduces the overall resistance of the device . As shown in Figure d, the specific capacitance of the device increases with increasing temperature, which conforms to the obtained law and proves that the device has good electrochemical performance at high temperature.…”

“…This is mostly owing to the injection of ionic liquids [EMIM] [TFSI] and ChCl into the gel electrolyte, which adds ionic conductivity and reduces the overall resistance of the device. 31 As shown in Figure 5d, the specific capacitance of the device increases with increasing temperature, which conforms to the obtained law and proves that the device has good electrochemical performance at high temperature. And with the rapid transport and adsorption of electrolyte ions, the internal resistance of supercapacitors gradually decreases.…”

Ionogels: Preparation, Properties and Applications

“…The Wang group developed an ionogel electrolyte composed of [VMIM][TFSI], polyacrylamide, and MXene, which improved the conductivity of the electrolyte and the integrated area of the voltametric curve of the supercapacitor. [ 86 ]…”

Exploring the Potential of Natural Rubber as Electrolytes and Electrodes for Advanced Energy Storage Applications

“…[66] However, SPE has poor interface contact with the electrode, resulting in less performance of the devices. [67][68][69] Therefore, NR electrolyte has become the ideal substitute for SPE as it is more flexible and has better contact with the electrode for electrochemical reaction. Nevertheless, NR is insulating in nature with low dielectric constant, hence, several steps need to be taken to make it conductive as well as to increase its dielectric properties.…”