Utilization of single biomass-derived micro-mesoporous carbon for dual-carbon symmetric and hybrid sodium-ion capacitors

Abstract

Sodium-ion capacitors (SICs) have emerged significantly in the last few decades due to their high energy, high power with rapid energy deliverability, and sustainability quotient as an alternative to lithium-ion capacitors (LICs). In this study, a jute-based precursor-derived carbon is chemically activated with or without microwave pretreatment and tested in aqueous and non-aqueous symmetric and asymmetric SICs. The synthesized microwave pretreated activated carbon (AJPC-M) exhibits more defect and micro/mesoporosity with a high surface area of 1529.75 m² g⁻¹ with a high specific capacitance of 1166 F g⁻¹ at the current density of 1 A g⁻¹ and excellent rate capability of 470 F g⁻¹ at 10 A g⁻¹ in a three-electrode aqueous system. The symmetric sodium-ion capacitor (SSIC) with an AJPC-M-based capacitor in an aqueous medium delivered a high energy density of 37.7 W h kg⁻¹ at the specific power of 785 W kg⁻¹ and a maximum specific power of 7895 W kg⁻¹ with a specific energy of 9.75 W h kg⁻¹ at 1 A g⁻¹ and 10 A g⁻¹, respectively. 100% gravimetric capacitance is retained for 9000 cycles at 8 A g⁻¹. In the non-aqueous system, the AJPC-M cathode displays the specific capacity of 89 mA h g⁻¹ at the current density of 0.02 A g⁻¹. The symmetric sodium-ion capacitor (SSIC) in a non-aqueous system delivers a maximum energy density of 60 W h kg⁻¹ at a specific power of 510 W kg⁻¹ and a maximum specific power of 3570 W kg⁻¹. The concept checks on the hybrid sodium-ion asymmetric capacitor (ASIC) with activated carbon (APJC-M) as the cathode and hard carbon (JPC-D) as the anode, derived from the same jute-based precursor, delivered an improved performance with 86 W h kg⁻¹ at a specific power of 636 W kg⁻¹ and realized a maximum specific power of 3440 W kg⁻¹. The excellent electrochemical capacitance of the jute-derived micro-mesoporous activated carbon with more defects, high surface area, larger pore volume, and optimum pore size distribution demonstrates a cost-effective porous activated carbon for powering both anodes and cathodes for both symmetric and hybrid SIC devices.