Fully Stretchable Microbial Fuel Cell with 75% Stretchability

A decent stretchability is of paramount significance to operate microbial fuel cell (MFC) under mechanically dynamic conditions. However, it remains a grand challenge to fabricate fully stretchable MFC without compromising its power output. Here, using Shewanella oneidensis MR-1 (S. oneidensis) as the model electrogenic bacteria, the study demonstrates a fully stretchable MFC device that can operate with a stretchability of 75%. The design takes advantage of a stretchable and ion-conductive polyurethane membrane, which encapsulates the biohybrids composed of S. oneidensis and reduced graphene oxide (rGO) on the polydimethylsiloxane (PDMS) current collector for synchronous stretching. It is discovered that the "stretchable" living biohybrids can sustain an adaptive bio-current output under stretching/releasing stimulation. The design also employs a stretchable air cathode. The stabilized peak power density of the stretchable MFC follows an increasing trend with the applied strain, and reaches 5.0 ± 0.7, 5.9 ± 0.9, 6.2 ± 1.1, 6.6 ± 1.4 µW cm^-2 at strains of 0%, 25%, 50%, and 75%, respectively (n = 3). At 75% strain, the stretchable MFC yields a maximum current output of 104 ± 27 µA cm^-2 and an open-circuit voltage of 283 ± 30 mV (n = 3). The results provide insights to design stretchable MFCs to power the next-generation on-skin devices, soft robotics, and sustainable electronics.