Engineering built-in electric fields within Co3O4 /g-C3N4 heterostructures for enhanced electrochemical performance in supercapacitor

The construction of heterostructured energy storage and conversion with special morphology has the potential to be an up-and-coming area of research. In this study, we designed and synthesized a Co₃O₄/g-C₃N₄ heterostructured electrode material with a distinctive morphology using a multistep fabrication approach. The heterojunction formed between Co₃O₄ and g-C₃N₄ induces interfacial charge redistribution, resulting in a built-in electric field that facilitates efficient electron transfer and enhances the electronic structure. Furthermore, the engineered morphology, comprising nanocages and hollow tubes, significantly increases the number of electrochemically active sites. The optimized electrode achieved an impressive specific capacity of 921.8 F g −1 at a current density of 1 A g −1 , along with excellent cycling stability, retaining 82.88 % of its initial capacity after 10,000 cycles. Moreover, an asymmetric supercapacitor constructed with Co₃O₄/g-C₃N₄ as the positive electrode and activated carbon as the negative electrode demonstrated a stable and high energy density of 36.3 Wh kg −1 .