Toy-blocks-inspired programmable supercapacitors with high energy density

Inspired by toy blocks, programmable supercapacitors are developed based on two-head electrode blocks. The supercapacitors feature a wide potential window and a high energy density. [Display omitted] •Inspired by toy blocks, programmable supercapacitors are proposed.•The supercapacitors are based on two-head electrode blocks (THEBs).•The new-concept THEB is prepared through a facile in situ redox reaction method.•The supercapacitors feature a wide potential window and a high energy density.•The THEBs are designed to build a variety of programmable energy devices. Diversity and individuation development of wearable electronics require their power sources to be programmable and customizable. However, how to prepare all-purpose electrodes with high designability and satisfying energy density for power sources is still a serious challenge. Herein, we propose programmable supercapacitors based on novel electrode blocks, which are inspired from toy blocks. Polyaniline/carbon nanotube strip is adopted as electrode block template, where one end of the strip is loaded with capacitive MnO2 (4.9–12.4 mg cm−2) as the cathode head, while the other end is left untreated as the anode head. These two heads are designed with opposite potential windows, forming a 2.5 V asymmetric supercapacitor with a high areal capacitance (679.0 mF cm−2). The supercapacitor reaches a remarkable energy density of 513.3 μWh cm−2, which is further utilized to power a high power-consumption fan and an E-ink display. Finally, the electrode blocks are applied to programmably construct a variety of energy devices, such as high-voltage device, stretchable device, three-dimensional supercapacitor lantern and wirelessly self-charged display system. The concept of general electrode block together with its two-head feature to increase energy density will provide a new route to fabricate programmable power sources for the booming wearable electronics.