Flexible bioelectrode via in-situ growth of MOF/enzyme on electrospun nanofibers for stretchable enzymatic biofuel cell

• Encapsulating enzyme into ZIF-8 during in-situ growth of ZIF-8 on PU/RC blend nanofibers. • A stretchable EBFC with “sandwich” structure was constructed by bioelectrodes and hydrogel. • The designed stretchable EBFC exhibits stable energy output performance under multiple mechanical deformation states. Flexible and wearable energy devices have become an important support and indispensable product of the era of artificial intelligence and Internet of Things. Enzyme biofuel cells (EBFCs) have received much attention for their ability to convert the body's abundant biochemical energy into electricity. It is still a challenge to realize the flexibility of EBFC system and improve its stability under mechanical deformation. Therefore, we establish a laminated stack of EBFC that is fabricated by flexible enzymatic bioelectrodes and stretchable hydrogel. The bioelectrodes were synthesized through enzyme encapsulation and in-situ growth strategies based on polyurethane/ regenerated cellulose (PU/RC) nanofiber, since it has been proved that mental organic frameworks (MOFs) could effectively maintaining biological activity and nanomaterials could promote electron transport efficiency. The results show that a piece of as-fabricated stretchable EBFC (5 × 1 cm) demonstrates considerable energy harvesting while produces a E OCV of 0.35 V. More importantly, the stretchable EBFC exhibits stable energy output performance even under repeated stretching, bending and twisting cycles. The assembled EBFC with stable output performance under multiple mechanical deformation states in this work shows important practical application value in the field of wearable energy devices.