Fabrication and performance test of biodegradable supercapacitor

Power source plays an important role in keeping normal functions of biodegradable electronic devices. In this paper, we proposed a fabrication method of biodegradable supercapacitor (BSC), which can provide energy for portable and implantable medical electronics. The BSC has a sandwich-like symmetric structure, which was assembled layer by layer. The electrochemical performances of BSC were measured, including the cyclic voltammetry test, galvanostatic charge-discharge and electrochemical impedance spectroscopy. Titanium foil was used as a template to generate microstructure for polylactic acid (PLA) supporting substrate. The microstructure provided strong adhesion force for iron film in sputtering process. The nanoporous zinc oxide layer was prepared by evaporation-driven self-assembly technology on iron film. The nanoporous structure was in favour of ionic storage in charging-discharging process. About 60% of capacitance retention was achieved after 3000 times of cycling test. After connecting three BSC in series, a green LED pattern was lighted up immediately, indicating that the energy was stored in BSC device successfully. After immersing the BSC in DMEM, the BSC can be totally degraded gradually. This work provided a feasible scheme for developing biodegradable energy storage device, it also gave a possible avenue for powering biodegradable electronic devices.