Preparation And Performance Of Carbon-based Composite Coating Integrated Electrode Materials

With the development of society,the rapid development of electronic products and new energy vehicles has made a demanding requirement on energy storage equipment.Lithium ion batteries are widely used in various fields due to its high capacity,long life and friendly environment.The lithium ion battery with graphite as the electrode material cannot meet the demand of the market,so researchers make much effort to develop new electrode materials with higher capacity.Transition metal oxides are promising anode materials for lithium ion batteries because of their higher theoretical capacity.However,in process of charging and discharging,their significant volume effect seriously influences their electrochemical performance.In this paper,preparation of composites containing carbon and transition metal oxides as integrated electrodes was conducted to solve the above problems and improve their electrochemical performance.Molybdenum dioxide?Mo O₂?has a high theoretical capacity?838 m Ah/g?,good conductivity(greater than 1×10⁴Scm^-1)and ion transport performance.Mo O₂-C composite coating as integrated electrode was prepared through combining it with carbon.In the composite coating,Mo O₂nanoparticles are encapsulated in carbon matrix,and the special structures give it good electrical properties.Its initial discharge capacity,charging capacity and coulomb efficiency are 1342 m Ah/g,959 m Ah/g and71.44%respectively.At a current density of 100 m A/g,the capacity maintains 814m Ah/g after 100 cycles.At current densities of 200?500?1000?2000 and 5000 m A/g,the average specific capacities are 809?697?568?383 and 188m Ah/g respectively.The Mo O₂-C composite coating electrode has excellent electrochemical performance,which is attributed to the nanometer size,porous structure of the material,and the close combination of composite coating with copper foil.Fe₂O₃with high theoretical capacity?1007 m Ah/g?is rich in natural resources and pollution-free.In this paper,Fe₂O₃-C composite materials with three dimensional network structure are prepared by knife coating and subsequently sintering,and Fe₂O₃nanoparticles are distributed uniformly in carbon matrix with three-dimensional network framework structure.In charge and discharge cycle,it can provide buffer space for the volume expansion of Fe₂O₃nanoparticles.The stable Fe₂O₃-C composite structure can improve the cyclic and rate performance of the material.During the cycle,the composite delivers a discharge capacity of 1100.043 m Ah/g after 100 cycles at a current density of 100m A/g without capacity fading during cycling.In rate performance testing,at current densities of 100?200?500?1000?2000 and 5000 m A/g,the specific capacities are 1224?1164.82?1035.11?923.85 and 802.36 m Ah/g respectively.In this experiment,knife coating and subsequent sintering at high temperature were employed to synthesize carbon based composite coating as integrated electrode material.The route is simple and suitable for large scale production;the obtained electrode material delivers excellent electrochemical performance,so our work has promising commercial application.