Electrochemical field emission effect of ordered bismuthene electrode for supercapacitive iontronic skin with high thermal adaptability

Abstract

In a biomimetic iontronic electrochemical system, the interior ions can move accompanied by surrounding charges, and then facilitating the integral carrier transfer, yet their transfers are still restricted by concentration gradient and temperature. Here, an ordered porous bismuthene electrode is designed, composed by bismuthene, bismuthene-derived Bi2O3&BiOCl, and borophene materials, with supercapacitive 4.96 F g−1 attribute retaining 89.6 % after 29,600 cycles, and the dispersive bismuthene nanosheets are also embedded into regenerated silk fibroin as elastic electrolyte. The resultant symmetrical iontronic pressure sensor shows high sensitivity of 2.31 kPa−1 in a wide 0.2–10 kPa range, and 0.41 kPa−1 sensitivity ranging 10–48 kPa, fast response/recovery time of 60/50 ms, and low detection limit of 0.45 Pa. The simulation and mechanism analysis demonstrate that a field emission effect plays an important role in electrolyte, in which the ions around the ordered bismuthene as emitters are launched and moved along the inner bismuthene nanosheets, step by step, to enormously shorten the ions migration path and effectively accelerate ion-charge pair transfer. Compared to the device without bismuthene in electrolyte, the sensitivity of sensor is improved by 23.81 times with high reproducibility over 1000 cycles. Additionally, the poly (3, 4-ethylenedioxythiophene): poly (styrene sulfonate) in electrolyte effectively constrains the movements of polymer molecules, contributing to high temperature adaptability from −15 to 70 ℃. In practical application, a tiny pressure monitoring in hot/cold perception is demonstrated, revealing a promising application in wearable systems and intelligent robotics.