A Ti₃C₂T_x-encapsulated Mn<SUP>2+</SUP>-doped Co(OH)₂ nanosheets electrode grown on carbon cloth for low-temperature flexible supercapacitors

Key Words:ACTIVATED CARBON; HIGH-PERFORMANCE

Abstract:In general, most flexible supercapacitors with excellent performance at room temperature cannot work properly at relatively low temperatures (such as 0 degrees C), mainly due to the poor cold resistance of the electrodes and electrolytes. In this paper, the carbon cloth was coated with positively charged Mn2+-doped Co(OH)2 coating by electrodeposition and then impregnated with negatively charged Ti3C2Tx nanosheets suspension (This electrode is named CC@Co(OH)2:Mn2+@Tx, Where x is the number of impregnation Ti3C2Tx.). The results show that the obtained electrode has a good supercapacitor performance with the specific capacitance of 22.13 F g- 1 (the area specific capacitance of the sample is 202.5 mF cm- 2), which is attributed to the synergistic effect of Ti3C2Tx and the flower microstructure of Mn2+-doped Co(OH)2 coating. Ti3C2Tx was introduced to polyvinyl alcohol/sodium alginate hydrogel electrolyte to obtain a new antifreezing organohydrogel and then a flexible asymmetric supercapacitor was assembled with CC@Co(OH)2:Mn2+@T3 as the positive electrode, CC@T3 as negative electrode, and the performance of the supercapacitor at 25 degrees C and at 0 degrees C were investigated. It was found the supercapacitor exhibited better performance at 0 degrees C instead of 25 degrees C. When the current density is 5 mA cm- 2, the area specific capacitance of the supercapacitor at 0 degrees C reaches 52.02 mF cm-2. After 1000 cycles, the supercapacitor has a capacitance retention rate of 82.5 % at 0 degrees C, which is much higher than that of 55.15 % at 25 degrees C. The reason may be related to the Ti3C2Tx and the crosslinked networks structures of composite hydrogel. The results show that the supercapacitor has excellent working ability at 0 degrees C, which provides the possibility for the device to work normally in low temperature.

Volume:513

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Translation or Not:no