Direct laser writing of graphene films from a polyether ether ketone precursor

Graphene-based micro-supercapacitors exhibit excellent electrochemical performance that can easily meet the energy storage requirements of micro-electronic products. However, the complex preparation and transfer process steps of traditional preparation methods limit their wide application. Direct laser writing can deposit graphene laser-induced graphene (LIG) onto a specific substrate-patterned electrodes. This approach offers great advantages in the preparation of miniature and complex-patterned electrodes, but currently there is a limited choice of precursor materials. In this reported study, biocompatible polyether ether ketone (PEEK) was irradiated using a high repetition rate picosecond laser to produce graphene. Various photothermal and photochemical reactions were involved in the one-step conversion of PEEK into a film comprised of a several layers (3–4) of graphene. The electrochemical testing of a three-electrode system containing this novel graphene showed that LIG had a specific capacitance of 20.4 mF cm⁻² at a scan speed of 10 mV s⁻¹, and the capacitance was reversibly maintained with 89.37% retention of the initial capacitance after 5000 cycles. The novel LIG with higher specific capacitance and cycle stability has great potential for use in energy storage micro-devices.