Rolled-up island-bridge (RIB): a new and general electrode configuration design for a wire-shaped stretchable micro-supercapacitor array†
Wire-shaped stretchable supercapacitors could be a promising candidate for a compatible energy supply unit for wearable electronics. However, great challenges still exist in simultaneously achieving the goals of high energy density, large elongation, stable electrochemical output, and excellent integration capability and washability. Herein, a “rolled-up island-bridge (RIB)” architecture design is demonstrated for fabricating a novel wire-shaped stretchable micro-supercapacitor array (WSS-MSCA) to concurrently realize the above objectives. The obtained WSS-MSCA, consisting of rolled-up MXene//CNTs@PPy asymmetric MSC arrays serving as active islands interconnected by screen-printed semi liquid metal (LM) circuits functioning as conductive/stretchable bridges, can deliver a maximum linear/areal capacitance of 29.45 mF cm−1/26.80 mF cm−2, while functioning well under extreme deformations such as stretching to 100% strain, bending to 180° and twisting by 360°. Combined with an extended potential window up to 1.4 V, a high linear/areal energy density of 7.94 μW h cm−1/7.22 μW h cm−2 is further achieved. Most notably, the unique RIB electrode layout guarantees outstanding integration capability of the MSC array, enabling on-demand output of the voltage/current with its convenient series/parallel interconnection via LM bridges and ensuring unprecedented adjustability to the whole electrochemical performance of the device. Moreover, the modular nature of the RIB architecture combined with the waterproof and stress-absorbing elastic silicone encapsulation matrix provides the WSS-MSCA with excellent mechanical robustness and additional washability. The stable and controllable electrochemical output, and excellent deformability and washability, combined with outstanding integration capability and appropriate length make the WSS-MSCA a promising compatible micro-power source for wearable microelectronics.