A coaxial wet-spinning approach is introduced to fabricate polyelectrolyte-wrapped graphene/carbon nanotube (CNT) core-sheath fibres, which are directly used as safe electrodes for two-ply yarn supercapacitors (YSCs). These YSCs, using liquid and solid electrolytes, achieve ultra-high capacitances of 269 and 177 mF cm⁻², and energy densities of 5.91 and 3.84 μWh cm⁻², respectively. A cloth supercapacitor with higher capacitance than commercial capacitors is interwoven from two 40-cm-long coaxial fibres. The combination of scalable coaxial wet-spinning technology and high-performance YSCs enables the development of wearable and safe electronics. The YSCs are fabricated by intertwining two coaxial fibres and coating them with a PVA/H₃PO₄ gel electrolyte. The YSCs exhibit excellent electrochemical performance, with high capacitance, energy density, and cycling stability. The coaxial fibres are flexible, robust, and can be woven into textiles. The YSCs also demonstrate high rate capability and excellent performance under bending and series/parallel connections. The results show that the coaxial wet-spinning approach is a promising method for developing high-performance YSCs for wearable electronics.A coaxial wet-spinning approach is introduced to fabricate polyelectrolyte-wrapped graphene/carbon nanotube (CNT) core-sheath fibres, which are directly used as safe electrodes for two-ply yarn supercapacitors (YSCs). These YSCs, using liquid and solid electrolytes, achieve ultra-high capacitances of 269 and 177 mF cm⁻², and energy densities of 5.91 and 3.84 μWh cm⁻², respectively. A cloth supercapacitor with higher capacitance than commercial capacitors is interwoven from two 40-cm-long coaxial fibres. The combination of scalable coaxial wet-spinning technology and high-performance YSCs enables the development of wearable and safe electronics. The YSCs are fabricated by intertwining two coaxial fibres and coating them with a PVA/H₃PO₄ gel electrolyte. The YSCs exhibit excellent electrochemical performance, with high capacitance, energy density, and cycling stability. The coaxial fibres are flexible, robust, and can be woven into textiles. The YSCs also demonstrate high rate capability and excellent performance under bending and series/parallel connections. The results show that the coaxial wet-spinning approach is a promising method for developing high-performance YSCs for wearable electronics.