CVD Design Of Anode Matorials For Sodium/Potassium Ion Batteries Apolications

With the increasing development of energy storage devices and the improvement of social demand,the reserves of lithium resources are becoming increasingly scarce.Sodium/potassium have similar physical and chemical properties to lithium,and their abundant storage and low price make sodium/potassium ion batteries more competitive in the future energy storage field.However,because the sodium/potassium ion radius is too large,the electrochemical kinetics is slow,and the energy density cannot meet the market demand,which seriously hinders the commercialization process.Aiming at the key issues in the sodium/potassium energy storage system,we focus on the design of the anode material and utilizes graphene to build a conductive network to effectively manage ion diffusion and electron conduction,accelerate the kinetic process in the electrochemical process,and effectively improve the ion storage.The main research contents of this thesis as follow:1.First,vertical graphene arrays are grown on a carbon cloth by a plasma-assisted chemical vapor deposition method,and then combined with hydrothermal and thermal selenization methods to in-situ compound CoSe2 nanoparticles.The composite structure was used as a negative electrode of a sodium ion battery.The study found that the vertical graphene arrays effectively improve the overall conductivity of the anode system,significantly improves the rate performance of the system,and improves cycle stability.2.In addition,a two-step chemical vapor deposition method was used to synthesize nitrogen-doped graphene and ReSe2 heterojunction structures on a three-dimensional MXene substrate for the study of the performance of potassium ion batteries.An in-situ ion diffusion network was constructed to accelerate ion transport and electrons conductivity,promote the electrochemical reaction process,effectively improve the rate and cycle performance,and combine the first-principles calculations to reveal the multi-party synergy in the potassium ion storage process.The constructed potassium ion battery can exert a capacity of 137.5 mAh g-1 at a current density of 10 A g-1.Such a heterojunction structure design provides research ideas for high performance alkaline metal battery anode systems.