Stretchable MXene based films towards achieving balanced electrical, mechanical and energy storage properties

Ti3C2Tx MXene with superior electrical, mechanical and electrochemical properties has attracted tremendous interest in flexible electronics. However, it remains challenging to transfer these prominent properties to stretchable MXene films with uncompromising properties due to the small flake size and weak interlayer interactions of MXene. Here, by using large sized MXene (LMX, ∼10 μm) with continuous overlap rate, and the synergistic effects of covalent and hydrogen bonds between PVA and LMX, we achieve stretchable polyvinyl alcohol (PVA)/LMX films that can simultaneously possess high mechanical strength (∼280 MPa), electrical conductivity (∼6240 S cm−1) and energy storage capability (∼364F g−1) under different tensile strains ranging from 0 to 150 %. The as-assembled stretchable supercapacitor device demonstrates high capacitance retention of nearly 100 % under stretching rates at 50 %, 100 % and 150 %, or bending rates at 90° and 180°. Impressively, the device also displays good reliability and safety that can maintain its performances under repeated stretching (at 100 % strain) or bending (180°) after 1000 cycles. Thus, the development of stretchable MXene based films with uncompromised properties is expected to broaden their applications for wearable electronics in future commercialization.