Clean energy storage devices in electricity market under dual carbon goals: assembly and performance of supercapacitors

Against the strategic backdrop of the coordinated development of the dual-carbon economy and the ecological economy, the electricity market has put forward stringent requirements for the efficiency and stability of clean energy storage devices. To break through the bottlenecks of traditional energy storage technologies, this paper focuses on the assembly process and electrochemical performance optimization of supercapacitor energy storage devices, and designs and fabricates an asymmetric supercapacitor with La-Ce co-doped nickel molybdate (La, Ce-NiMoO₄) as the positive electrode and carbon nanotube/tin dioxide (CNTs/SnO₂) composite as the negative electrode. Through characterization methods such as XRD, SEM, TEM, and XPS, the successful doping of La and Ce elements and their regulatory effects on the crystal structure and microstructure of the cathode materials are confirmed. Meanwhile, the heterojunction interface characteristics and conductive network structure of the CNTs/SnO₂ negative electrode are clarified. With the help of cyclic voltametric measurements, galvanostatic charge-discharge tests, cycling stability, and EIS measurements, the energy storage performance and charge transfer mechanism of the asymmetric cell under various current densities and voltage windows are systematically investigated. The results show that La-Ce co-doping effectively improves the electron conduction efficiency and ion diffusion rate of nickel molybdate. The three-dimensional conductive network of the CNTs/SnO₂ negative electrode can promote rapid charge transfer and mitigate the volume expansion effect of SnO₂. The assembled device achieves a specific capacitive value of 195 F·g⁻¹ at a current load of 1 A·g⁻¹, a value of energy density of 71.2 Wh·kg⁻¹, and a capacity retention rate of 94% following 10,000 cycles, together with outstanding rate performance and long-term cycling stability. This study provides a new type of positive and negative electrode matching scheme and device assembly ideas for the upgrading of clean energy storage technologies in the electricity market under the dual-carbon goals, contributing to the market-oriented development of the ecological economy-oriented energy storage industry.