Study On Properties And Modification Of Carbon Fiber Brush As Cathode Material For Seawater Battery

The importance of the ocean in all countries of the world has become more and more prominent since the beginning of the 21 st century.It becomes more and more clear of necessity to develop marine economy and marine science and technology,both in terms of national economy and national defense security.Special marine instruments are used in the development and utilization of the ocean,since the ocean is different from the land.The physical medium is required for power transmission in the general method of providing energy for marine instruments,the battery can solve this problem,but there is a great hidden danger in terms of safety and the like when the conventional battery is applied to the marine environment.The new safer and more efficient battery has a brighter application prospect,and the metal–dissolved oxygen seawater battery that can be designed as an open structure undoubtedly meets our requirements in many aspects.In this paper,a graphene oxide–carbon fiber composite electrode was prepared by electrophoretic deposition using a carbon fiber brush as the carrier and graphene oxide as the catalyst.Some performances were tested on the composite electrode,including the open circuit potential(OCP),cyclic voltammetry(CV),constant current discharge,potentiodynamic polarization curve,current–time curve and scanning electron microscope(SEM).The composite electrode and AZ63 magnesium alloy were constituted a magnesium–dissolved oxygen seawater battery and the full battery was subjected to the unloaded seawater battery stability voltage test,the seawater battery constant resistance discharge performance,the seawater battery constant current discharge performance test in dynamic seawater and the battery performance comparison study in dynamic and static seawater.The main conclusions of this paper are as follows:1?Electrophoretic deposition is an excellent method for modifying the surface of carbon fibers,which can attach graphene oxide to the surface of carbon fibers.The properties of the modified carbon fiber are improved compared to the unmodified pure carbon fiber.When the deposition voltage is 20 V,the deposition effect observed from the surface is the best.2?The composite electrode combines the good electrical conductivity of carbon fiber and the catalytic ability of graphene oxide.It not only does not destroy the electrical conductivity of carbon fiber,but also adds catalytic ability that it did not have.The carbon fiber brush of this specification used in this article has an optimum current of 3 mA.AZ63 magnesium alloy is a typical anode material.The battery voltage is larger,the stability is better,the activation time is short,and there is almost no hysteresis after forming a seawater battery with a composite electrode.3?Dynamic seawater will have a certain impact on the performance of the battery compared with static seawater,and the effect of different seawater flows on the surface reaction of the electrode is also different.The electrochemical reaction of the electrode surface is controlled by electronic transfer and diffusion simultaneously when the electrode is facing or facing away from the water flow direction,and the overall reaction process is not affected by the cathodic reaction.The electrode reaction process is mainly controlled by the electronic transfer process when the electrode side faces the water flow direction,and the diffusion process has little effect,and the cathodic reaction becomes the limiting factor of the overall reaction.4?A seawater battery was designed with a maximum battery voltage of about 1.74 V and a stable voltage of around 1.50 V.In order to keep the battery voltage above 0.8 V,the resistance should be above 10 ?,and the maximum power is when the load is 15 ?,the maximum power is 66.67 mW.