A novel all graphene coaxial fiber supercapacitor (GCS) was fabricated, consisting of a continuously wet-spun core graphene fiber and facilely dip-coated graphene sheath. GCS is flexible, lightweight and strong, and is also accompanied by a high specific capacitance of 205 mF cm−2 (182 F g−1) and high energy density of 17.5 μW h cm−2 (15.5 W h kg−1). The energy density was further improved to 104 μW h cm−2, when an organic ion liquid electrolyte was used.
