Nitrogen-doped polyporous carbon shell frame as enzyme nanocarrier for flexible enzyme fuel cell

As a clean and efficient energy generator, enzyme fuel cells are expected to be the next generation of wearable and implantable bioenergy harvestor. The nitrogen-doped hollow carbon shells have been previously proven to be one of the most successful enzymes nanocarriers to increase the direct electron transfer rate between enzymes and electrode. The tightly and uniformly attachment of nanocarriers on the flexible collector still remains a challenge. In this work, we use the hydrothermal method and etching process to prepare the nitrogen-doped polyporous carbon shell frameworks on commercial carbon cloth. The good mechanical properties of the hydrogel ensure that the device can adapt to different stresses and strains generated by individual movement. The open-circuit voltage of the biofuel cell loaded with modified bioanode reaches 0.43 V, the maximum power density is 22 μW cm−2, which is twice of that using conventional protocals. The long-term power output is kept stably, and its power density has limited fluctuations during the repeated stretching, twisting and washing processes due to tight and uniform connections between flexible current collector and nanocarriers. It provides a continuous stream of energy under practical conditions, proving that the proposed strategy has great potential for developing flexible and stretchable wearable devices.