Scalable assembly of flexible ultrathin all-in-one MXene-based supercapacitors

Supercapacitors are promising candidates for flexible energy storage devices as a result of their long cycle life and high power density. However, their scalable assembly is still challenging. Herein, a facile blade coating method is employed to realize the fabrication of flexible ultrathin supercapacitors with an integrated all-in-one configuration. The assembly of such supercapacitors can be easily scaled up by adjusting the area of substrates. The all-in-one structure effectively integrates two MXene electrodes, a gel electrolyte and a separator. As a result, they can not only enhance ion- and electronic-transfer capability, but also avoid the slippage or separation between adjacent components under frequent external strain. Moreover, owing to the unique physical and chemical properties of the MXene electrode as well as the structure and electrochemical stability of the integrated all-in-one configuration, the resulting supercapacitors exhibit excellent electrochemical properties, such as a high specific areal capacitance of 77.25 mF cm⁻² at 2 mV s⁻¹, a long cycle life of 16 000 cycles at 2 A g⁻¹, high rate ability and superior electrochemical stability even under varied bending states.