Implantable devices powered by batteries have been used for sixty years [1]. In recent devices, lithium-based batteries are the most widely used power source [2]. However, lithium batteries have many disadvantages in terms of safety, reliability, and longevity and require regular monitoring and substitution. Implantable glucose biofuel cells are increasingly seen as a potential future technology for replacing lithium-based batteries because they do not require a surgical replacement after 8-10 years and have a theoretically unlimited lifetime thanks to the continued recovery of glucose and oxygen present in the human body. In this paper, we show the fabrication of flexible implantable abiotic cathodes, based on Nitrogen/iron-doped graphene catalyst, for glucose/oxygen biofuel cells application. An ink, based on nitrogen-iron doped graphene as the abiotic catalyst and chitosan as a binder, was prepared and coated on a flexible teflonated gas diffusion layer using doctor blade coating. The characterization of the biocathode shows an open potential circuit corresponding to the potential of the abiotic catalyst and a high oxygen reduction current density up to 66 µA/cm 2 under physiological conditions. Those cathodes remain stable for up to two years with a current density loss of only 25%. The flexible abiotic electrode was tested in an assembled biofuel cell where an enzymatic anode, previously fabricated by our group, was used. The hybrid biofuel cell delivers a high-power density up to 220 µW cm −2 and an open-circuit voltage of 300 mV under physiological conditions (5 mmol l −1 glucose, pH=7.4).