Sulfur and nitrogen co-doped graphene electrodes for bioinspired ionic artificial muscles, which exhibit outstanding actuation performances (bending strain of 0.36%, 4.5 times higher than PEDOT:PSS electrodes, and 96% of initial strain after demonstration over 18 000 cycles), provide remarkable electro-chemo-mechanical properties: specific capacitance, electrical conductivity, and large surface area with mesoporosity.