Filling Ti₃C₂T_x nanosheets into melamine foam towards a highly compressible all-in-one supercapacitor

The development of compressible supercapacitors strongly relies on the design of electrode materials combining superior compressibility, high conductivity with the stable electrochemical cycling performance. In this work, we report a facile yet scalable strategy to construct a highly compressible supercapacitor by integrating the current collector, active materials and the separator into one device. We use the highly compressive melamine foam (MF) as scaffold and the Ti₃C₂T_x nanosheets as the active materials. Filling the few-layer Ti₃C₂T_x nanosheets into the skeleton of MF by capillary force followed by freeze-drying yields the MF/Ti₃C₂T_x composite with superior structural integrity that can be compressed at a large strain of 50% for 100 cycles. The electrochemical performances of the all-in-one supercapacitor were systematically investigated under diverse compression strains. The improved conductivity and reduced ion diffusion length allow the all-in-one supercapacitor to exhibit fast ion and electron kinetics even at high strain of 60%, delivering a maximal volumetric specific energy of 0.37 mWh∙cm⁻³ at power density of 0.42 mW∙cm⁻³ and extraordinary cycling performance during the 2,500 compression cycles.