Ti₃C₂T_x, a novel two-dimensional layer material, is widely used as electrode materials of supercapacitor due to its good metal conductivity, redox reaction active surface, and so on. However, there are many challenges to be addressed which impede Ti₃C₂T_x obtaining the ideal specific capacitance, such as restacking, re-crushing, and oxidation of titanium. Recently, many advances have been proposed to enhance capacitance performance of Ti₃C₂T_x. In this review, recent strategies for improving specific capacitance are summarized and compared, for example, film formation, surface modification, and composite method. Furthermore, in order to comprehend the mechanism of those efforts, this review analyzes the energy storage performance in different electrolytes and influencing factors. This review is expected to predict redouble research direction of Ti₃C₂T_x materials in supercapacitors.

A solid-state supercapacitor with a flexible, simple structure based on graphene thin film electrodes and acid/base/salt–PVA gel electrolytes is reported. The performance of six different gel electrolytes (H₃PO₄, H₂SO₄, KOH, NaOH, KCl, NaCl) in this graphene-based supercapacitor are investigated. The electrochemical properties of this highly flexible, stable supercapacitor are enhanced by optimizing the concentration of the electrolyte in polymer gel.

We report the design and preparation of graphene and polyaniline (PANI) woven-fabric composite films by in situ electropolymerization. The introduction of PANI greatly improves the electrochemical properties of solid-state supercapacitors which possess capacitances as high as 23 mF cm⁻², and exhibit excellent cycling stability with ∼100% capacitance retention after 2000 cycles. The devices have displayed superior flexibility with improved areal specific capacitances to 118% during deformation.