Preparation And Ultracapacitance Properties Of High Performance Nickel Copper Compound Electrode Materials

As a new type of electrochemical energy storage device,supercapacitor exhibits excellent performance in various aspects such as power density,cycle life and charge/discharge rate,but the application of supercapacitor is limited by its low energy density.The electrode materials are the core part of supercapacitor,and the reasonable design of electrode material shape,structure and components is the key to constructing high performance supercapacitor.Among them,transition metal oxide/hydroxide has become a potential electrode material due to its high theoretical specific capacity,but its poor rate performance and cycling stability are difficult to meet the demand of high-performance devices in practical applications.In this paper,high performance transition metal oxide/hydroxide composites were prepared by optimizing the synthesis process,combining with defects and interfacial control methods.Details are as follows:1.Bimetallic Ni-Cu oxide（NCO-Ar/H₂-10）nanosheet electrode materials with oxygen vacancy-rich and edge"sawtooth"structures were synthesized on nickel foam substrates by hydrothermal,annealing and plasma treatment processes.The NCO-Ar/H₂-10 electrode achieved excellent electrochemical performance including high mass specific capacity（1524 F/g at 3 A/g）,good rate performance（72%）and excellent cycling stability（109%capacity retention after 40000 cycles）by virtue of the synergistic effect between multiple phases and the modulation of defects within the material.In addition,the assembled devices exhibited an energy density of 48.6 Wh/kg at a power density of 799.6 W/kg,and the capacity retention and coulombic efficiency of 117.5%and 99.7%after 10000 cycles,respectively.2.“Pine tower”shaped Cu O@Ni Co-OH core-shell heterogeneous electrode materials were grown on copper foam substrates by in-situ oxidation reaction,annealing treatment and electrochemical deposition.Cu O@Ni Co-OH electrode exhibited a series of excellent electrochemical performance including high area specific capacity(7.97 F/cm² at 10 m A/cm²),excellent rate performance（84.8%）and good cycle stability（69.4%capacity retention rate after 10000 cycles）due to its unique morphological structure,which can facilitate full penetration of electrolyte and accelerate the charge transfer process.Moreover,the corresponding device achieved an energy density of 132.7 Wh/kg at a power density of 2666.7 W/kg,and the capacity retention rate and coulomb efficiency can reach 106.5%and 99.6%after 6000 cycles,respectively.