The Direct Spinning Of Fiber-shaped Graphene Supercapacitors And Their Performance

The emerging fiber-shaped supercapacitors have motivated tremendous research interest in energy storage devices.Graphene fiber is one of the preferred materials for preparing a supercapacitor,because of its high specific surface area,good conducfivity,light weight and so on.However,the traditional step-by-step preparation process of fiber-shaped graphene supercapacitors is complex and it is difficult to achieve direct and effective control of the fiber structure.Here,a simple direct wet spinning technique is proposed.By controlling and optimizing the structure and movement method of spinneret,the concentration of the spinning solution and the injection speed,a direct and controllable preparation of fibers with side-by-side,double helix and three-layer core-sheath structure was realized and applied to the fiber-shaped graphene supercapacitors.The specific research content is as follows:?1?By controlling the injection speed and concentration of the gel electrolyte,spinning solution and spinning parameters such as reductant,the fibers of the side-by-side structure,double helix structure and three-layer core-sheath structure were successfully prepared.?2?The mixed solution of graphene oxide?GO?and ascorbic acid?VC?,and carboxymethyl cellulose?CMC?gel solution were employed as spinning dopes,the fiber-shaped graphene supercapacitors with side-by-side and double helix structure were successfully prepared via a direct spinning method.The obtained supercapacitors show good flexibility and cycle stability.The specific capacitances of the side-by-side and double helix structure supercapacitors were 131 and 147 mF cm^-2,respectively.When the polyaniline was doped,the specific capacitance increased to 149 and 162 mF cm^-2,respectively.The fracture elongation and the tensile strength of the double helix fiber-shaped graphene supercapacitors reached 23²5%and 370⁴12 MPa,respectively.?3?A uniform mixing dispersion of GO and VC was injected into the inner and outer channels while the aqueous solution of CMC with ionically conductive polyelectrolyte was injected into the middle channel,and a three-layer core-sheath fiber-shaped graphene supercapacitor was successfully prepared by wet spinning.The performance of the supercapacitors with different CMC concentrations was optimized,and the optimal CMC concentration for the prepared supercapacitors was 5.5 mg mL^-1.The supercapacitor has good flexibility and cycle stability.The specific capacitance was 249mF cm^-2,energy density and power density were 44?Wh cm^-2 and 4.81 mW cm^-2,respectively.The fracture elongation and the tensile strength reached 16¹7%and210²30 Mpa.When doped with polyaniline,the specific capacitance and energy density increased to 292 mF cm^-2 and 59?Wh cm^-2,respectively.