Preparation Of Gully-network Co₃O₄ Nanowire/Composite And Its Application In Supercapacitors

The exhaustion and uneven distribution of fossil fuels have led to serious environmental and economic problems,and the development of clean renewable energy has become an effective way to solve this problem.However,most of clean renewable energy has problems such as difficult storage and low utilization rate,so the development of high-efficiency energy storage and conversion devices has become a top priority.Supercapacitors with excellent performances such as safety,environmental protection and high cycle stability have become the most promising of many energy storage devices.As the core of supercapacitor,the performance of the electrode material largely determines the performance of the supercapacitor.Therefore,improving the performance of the electrode material has become the focus of research in recent years.Cobalt trioxide?Co₃O₄?is widely studied as a supercapacitor electrode material due to low pollution,low cost,and high theoretical specific capacity.However,due to its low conductivity,the actual specific capacity and cycle stability have a large gap compared with the theoretical value.Therefore,how to improve the actual specific capacity and cycle stability is still a problem that people need to solve.In this paper,the innovative design and preparation of the gully network Co₃O₄ and its composite electrode materials,which grow in situ on the nickel foam substrate,not only ensure the stability of the electrode structure,but also enhance the conductivity of the cobalt trioxide electrode materials and enhance the comprehensive electrochemical properties of the electrode materials.The main research contents are as follows:?1?The gully network Co₃O₄ nanowire array,which is grown in situ on nickel foam by hydrothermal method and annealing,has a special gully network structure that fixes all nanowires on nickel foam and improves the stability of electrode structure.As a battery type supercapacitor electrode,it exhibits a high specific capacity(582.8 C g^-1 at a current density of 1 A g^-1),and an ideal rate performance(The capacity retention rate is about 84.8%at 20 A g^-1),especially excellent cycle performance?capacity retention rate of 93.1%after 25,000 cycles?.When assembled into a hybrid supercapacitor with AC,the energy density is 33.8Wh kg^-1(224 W kg^-1)and has a 74%capacity retention after 10,000 cycles.?2?The gully network Co₃O₄@Co₃S₄ core shell structure is obtained by vulcanization reaction of gully network Co₃O₄ nanowire array.When applied as a supercapacitor electrode,a high specific capacity(1,347 C g^-1 at a current density of 1 A g^-1)and excellent cycle performance?capacity retention of 80.2%after15,000 cycles?were obtained.The hybrid supercapacitor with the AC electrode exhibited a high energy density of 44 Wh kg^-1(160 W kg^-1),especially with a capacity retention of 93.1%after 12,000 cycles.