Piezoionic transfer effect in topological borophene-bismuthene derivative micro-leaves for robust supercapacitive electronic skins

To gain high performance in electrochemical device, exquisite accelerating ion-electron transfer is an effective way. Here, a topological idea is realized to design a micro-leave electrode by patterning borophene-bismuthene derivative. The inner bismuthene offers high conductive skeleton, intermediate BiOCl and Bi2O3 derivative as ornament contribute to supercapacitive property, and the outer borophene layer not only boosts supercapacitive property, but also reserves the topological shape. Assisted by a hydrogel electrolyte on a flexible indium-doped tin oxide substrate, a robust pressure sensor is fabricated, in which a piezoionic transfer effect is demonstrated to induce fast ions extraction and migration kinetics among the topological micro-leaves. Then the specific capacitance of electrode increases by 2.483 times comparing with the micro-leaves without borophene. The resultant robust electronic skin sensor presents a comparable sensitivity of 1.60 kPa−1 in the tiny pressure range of ≈ 50–150 Pa, and sensitivity of 1.01 kPa−1 in 150 Pa-8.5 kPa, low detection limit as 0.59 Pa, fast response/recovery time (80/80 ms), wide detection range (∼220 kPa) and reliable capacitance retention of 97.92% even after 10000 cycles. This has been successfully used to monitor the physiological signals and illustrates potential application prospects in human-computer interaction.