Phosphorus doped graphene nanoribbons as efficient cathode for zinc-ion hybrid supercapacitors

Zinc-ion hybrid supercapacitors (ZIHS) are characterized by high energy density along with outstanding cycling stability and safety, positioning them as a promising solution for energy storage in portable electronics and electric vehicles. The design of cathode materials plays a crucial role in enhancing the performance of ZIHS. In the paper, we designed and synthesized a phosphorus-doped graphene nanoribbon (P-GR) and regulated the p-element content in P-GR. XPS showed that phosphorus was successfully doped into the graphene nanoribbons and the phosphorus content reached 4.66 %. P-GR combined with three-dimensional carbon/aluminum oxide/aluminum (CAAO) to obtain a P-GR@CAAO composite electrode. The solid state ZIHS with P-GR@CAAO as cathode exhibits excellent performance with an areal capacitance as high as 172.41 mF cm⁻² and a high energy density of up to 61.3 μWh cm⁻². The P-GR@CAAO based ZIHS also shows good stability over 10,000 charge and discharge cycles.