Superfast Electrodeposition of Newly Developed RuCo2O4 Nanobelts over Low‐Cost Stainless Steel Mesh for High‐Performance Aqueous Supercapacitor

Abstract The superfast (≈30 min) and template‐free electrochemical approach is developed to prepare the unique nanobelts‐architectured RuCo 2 O 4 thin films over the stainless steel mesh substrates. The vertically aligned and interconnected RuCo 2 O 4 nanobelts present sufficient interspace to provide more electroactive sites and shorten the diffusion path for electrolyte ions. Owing to their unique nanostructure and higher electrical conductivity, the RuCo 2 O 4 nanobelts exhibit excellent electrochemical features, including a specific capacitance of 1447 F g −1 , and excellent electrochemical stability (82.25% retention over 16 000 cycles). Additional electrochemical kinetic analysis is carried out to confirm whether the energy storage in the RuCo 2 O 4 electrode is limited by solid‐state diffusion or whether it is surface‐controlled capacitive. More importantly, the comprehensive cycling analysis is performed to identify the factors responsible for capacity reduction upon long‐term cycling. The RuCo 2 O 4 nanobelts based symmetric supercapacitor shows good supercapacitive characteristics and excellent specific capacitance (276 F g −1 at 2.5 A g −1 ) and specific energy (30 Wh kg −1 at a specific power of 200 W kg −1 ), which are superior to those of recently reported symmetric and asymmetric supercapacitor devices. This work presents a new electrode material for fabricating advanced high energy supercapacitor for different applications.