Three-dimensional block assembled wireless rechargeable supercapacitors

The wearable and portable devices have recently attracted significant interest, however, the further advancements in commercially available devices are still restricted by bulky connections between functional modules comprising the incompatible energy storage, complex fabrication process, and expensive electrocatalytic materials for functional electrode activation. Herein, we developed the wireless rechargeable supercapacitors (SCs) by integrating a commercial wireless charger and charging receptor with three-dimensional (3D)-printed SCs. To fabricate a cost-effective 3D-printed SC, a polylactic acid-based plastic substrate was prepared via a 3D-printing technique and the substrate was dip-coated with MnO2 and artificially restructured V2O5 composite inks. A poly(3,4-ethylenedioxythiophene)@graphene flake (P@G) was added to the ink, making V2O5 and MnO2-entrapped P@G (MVP@G) to enhance the electrical conductivity and catalytic activity of the MVP@G SC., We demonstrated that the MVP@G SC showed a specific capacitance of 40.3 mF·cm−2 within a potential window of 1.4 V and an energy density of 34 μWh·cm−2 at a power density of 70 μW·cm−2 with a 77 % cycling stability (capacitance retention) after 2,500 cycles. Additionally, we investigated the effect of the electrolyte cations (e.g., Li+, Na+, K+, and Mg2+) on the electrochemical performance of the MVP@G SC.