Synthesis Of High Performance Cobalt-based Selenide And Telluride Electrode Materials And Study On Properties Of Asymmetric Supercapacitors

The rapid advancement of human society has accelerated the consumption of nonrenewable resources on Earth.In order to comply with the sustainable development of society,the depleted fossil energy will gradually fade out of people's attention in the future.Green sustainable energy such as wind,solar and tidal energy will become the main source of energy.Changes in energy structure have also placed demands on modern energy storage equipment.As a kind of green clean energy storage equipment,supercapacitor has become a research hotspot with its high energy density and power density and good cycle stability.Electrode material,as the most important component of supercapacitor,directly affects the overall performance of the device,and is one of the hot research directions.Cobalt-based selenides and tellurides have the advantages of small size,high surface area,good electrical conductivity,etc.,and are highly promising supercapacitor electrode materials.But so far,the research on cobalt-based selenide and telluride is still shallow,and there are still many problems and gaps that need to be solved and filled.In this paper,the electrochemical properties of cobaltbased selenides and tellurides were studied with cobalt selenide(Co Se)and cobalt telluride(CoTe),including the following parts:(1)A one-step solvothermal process was designed.Firstly,Co Se nano-particle materials were prepared.The effects of different temperature and time on the product were discussed.The optimal synthesis route was studied and its electrochemical performance was studied in detail;(2)The Se element was replaced by the more conductive Te element,and the pure CoTe nanowire material was prepared by adjusting the process.The products under different reaction temperatures and reaction time were discussed,and the optimal synthesis conditions were studied.The best product was analyzed for detailed electrochemical performance;(3)For the problem of stacking and agglomeration of synthesized CoTe materials,CoTe@r GO composites were prepared by combining CoTe nanowire materials with reduced graphene oxide(r GO),and the advantages of r GO and the synergistic effect of the two were solved.The problem of stacking agglomeration has improved the performance significantly.The three-step experiment has a certain correlation before and after the experiment:Firstly,the synthesis process was designed,and the Co Se nano-particle material was synthesized for the first time and studied in detail.Secondly,in view of the relatively weak electrochemical performance of the Co Se nanoparticle material prepared in the previous step,the Se element was replaced by the Te element with similar chemical properties but higher conductivity and better performance.The CoTe nanowire material was synthesized for the first time.Subsequent detailed electrochemical performance analysis showed that the performance was improved and matched the expected results.Finally,the problems left in the previous step were solved by the combination of r GO and the CoTe@r GO composite material was synthesized.The performance was improved obviously and the experiment was successful.