High Gravimetric Capacitance MXene Supercapacitor Electrode Based on Etched Ti₃C₂T_x by Chemical Etching

Abstract

Ti3C2T x MXene is one of the most promising electrode materials for supercapacitors, but it often suffers in poor experiment gravimetric capacitance, which limits practical applications in industry needs. Herein, etched Ti3C2T x MXene with high gravimetric capacitance is prepared by chemical etching of MXene with concentrated alkaline solution. The intercalation of K+ and the scissor role of OH− can simultaneously enlarge the interlayer spacing and cut the size of sheets, which lead to the high active‐site concentration and cation diffusion. As a result, the etched Ti3C2T x MXene displays high gravimetric capacitance of 368.1 F g−1 at 2 A g−1 and outstanding cycling stability without capacitance loss over 5000 cycles at 6 A g−1,and the surface capacitance contribution in etched Ti3C2T x MXene occurs to a greater extent compared with the pristine MXene. Moreover, the effect of chemical etching on the supercapacitor performance and energy‐storage mechanism indicates that the active‐size concentration and cation diffusion could be maximized when the chemical etching conditions are appropriate, leading to the highest performance of etched Ti3C2T x MXene. Herein, it is demonstrated that the chemical etching approach is applicable to design MXenes with high gravimetric capacitance to maximize their potential applications in energy‐storage applications and other fields.

Progress of 2D MXene as an Electrode Architecture for Advanced Supercapacitors: A Comprehensive Review

“…The etching reaction in an alkaline solution leads to an increase in interlayer spacing and a size reduction, which causes an increase in the active sites of Ti 3 C 2 T x MXene and enhancement in cation diffusion. As a result, the e-Ti 3 C 2 T x MXene can attain a gravimetric capacitance of 368.1 F/g at a current density of 2 A/g …”

“…Compared to pure MXene films, MXene/V 2 O 5 films’ flexibility and electrochemical capabilities are improved. The electrode also has better specific capacitance and cycling stability . Rakhi et al reported for the first time that depositing ε-MnO 2 whiskers on the surface of MXene to form electrodes for aqueous pseudocapacitors with increased surface area improved electrochemical performances in an aqueous electrolyte .…”

“…As a result, the e-Ti 3 C 2 T x MXene can attain a gravimetric capacitance of 368.1 F/g at a current density of 2 A/g. 70 …”

“…The electrode also has better specific capacitance and cycling stability. 70 Rakhi et al reported for the first time that depositing ε-MnO 2 whiskers on the surface of MXene to form electrodes for aqueous pseudocapacitors with increased surface area improved electrochemical performances in an aqueous electrolyte. 148 Zou et al developed a self-assembly method to synthesize MXene/α-Fe 2 O 3 having a high specific capacitance of 405.4 F/g at the current density of 2 A/g.…”

Ti3C2Tx MXene‐Reinforced Natural Rubber Nanocomposites with Tailored Mechanical and Antiaging Properties

“…[2,13] Besides, MXene demonstrates excellent electrical conductivity, [14,15] thermal conductivity, [15][16][17] nontoxicity, [18] stiffness, [19] surface chemistry, [20][21][22][23] and mechanical properties. [24,25] Because of these properties, MXene has been widely utilized in flexible electrodes, [26,27] capacitors, [28,29] electromagnetic interference shielding (EMIS) materials, [14,30,31] biomedical devices, [2,32] environmental protecting films, [33] and photothermal and electrothermal converting materials. [34][35][36] In addition, MXene has been introduced to elastomers such as natural rubber (NR), [37] acrylonitrile butadiene rubber (NBR), [38] and styrene-butadiene rubber (SBR) [39] as a mechanical reinforcement.…”