| The detection electrode is an important core component of the ocean electric field detection device.Among them,the Ag/AgCl electrode is widely used in various ocean signal detection because of its high stability and low self-noise.In this paper,the current Ag/AgCl electrode has slow potential stabilization speed,solid-phase structure corrosion powdering,poor strength,and increased self-noise during the test.The preparation process of the precursor powder,the composition and structure of the electrode,etc.It has been optimized.Firstly,the AgCl powder was optimized from the three aspects of ball milling time,drying method,and surfactant modification;secondly,the composition of the electrode was adjusted by adding carbon fiber(CF)and silver halide.The influence and mechanism of the precursor powder properties and electrode composition on the microstructure and electrical properties of the composite electrode were explored.In addition,a self-made external electric field induction system was used to test the actual application performance of the electrode,and a composite electrode that can work normally in seawater environment was prepared.The results of the study are as follows:1.The preparation process of AgCl powder was optimized by solid-phase ball milling.Firstly,the influence of ball milling time on the AgCl reaction process was explored.The crystal state obtained by ball milling for 4 hours was the best and the particle size distribution was the narrowest.Secondly,the effects of thermal drying and freeze drying on the morphology of AgCl powder were compared and analyzed.The AgCl particles obtained by the drying method are fluffy and have the best dispersibility.Finally,a comparative analysis of cetyl trimethyl ammonium chloride(CTAC),sodium bis(2-ethylhexyl)sulfosuccinate(AOT)and sodium dodecyl sulfate(SDS)were compared and analyzed.The influence of superfine AgCl powder synthesis effect,0.1 mol/L CTAC has the strongest controllability,and the obtained powder has a uniform size and a particle size of less than 1?m;finally,the above The optimized AgCl was prepared into Ag/AgCl electrode,and its electrochemical performance was tested.The results show that the effective porosity of the Ag/AgCl electrode made after the optimization of AgCl powder is15.53%,the total porosity is 30.01%,the specific surface area is 9000.28 cm2·cm-2,and the exchange current density is as high as 83.75 mA·cm-2.The electrochemical reaction barrier is low,the electrode reaction resistance Rp is 0.564?,and the electrochemical self-noise is as low as 1.566 nV/?Hz.2.The composition and structure of the Ag/AgCl electrode are compositely modified.The effects of the single addition of carbon fiber,the single addition of AgBr,and the combined addition of the two on the performance of Ag/AgCl electrodes were explored.The results show that the addition of carbon fiber can effectively increase the specific surface area of the electrode,thereby accelerating the electrode stabilization speed,and can also enhance the strength of the electrode itself.The addition of AgBr can effectively slow the substitution of Br?in the seawater for Cl?in the electrode,thereby improving the corrosion resistance of the electrode and reducing the degree of powdering damage of the solid phase structure of the electrode.When the carbon fiber is 1.5 mol and the molar ratio of AgCl and AgBr is 7:3,the composite electrode has the best performance.The open porosity is18.02%,the total porosity is 36.89%,and the specific surface area is 12422.39 cm2·cm-2.,The exchange current density is 76.09 mA·cm-2,the electrode reaction resistance Rp is1.479?,and the noise level at 1 Hz is 5.99 nV/?Hz,which meets the requirements for use.3.Use the self-made external electric field induction system to test the actual application performance of the electrode.Under the condition of simulating real sea water,the electrode length,short-term potential stability and external electric field induction characteristics of various frequency amplitudes were tested.The results show that the induced waveform of the electric field signal outside the optimized composite electrode is complete and distortion-free.The short-term potential is increased from 1 m V to below 0.1m V,which is an order of magnitude higher,and the long-term potential changes little.Among them,the composite electrode with carbon fiber of 1.5 mol and AgCl and AgBr molar ratio of 7:3 has the best stability.The short-term stable potential for 24 h is about0.08 m V,and the short-term potential difference drift is less than 0.03 m V.After 180 days of immersion,the long-term stable potential is-0.07 m V for 24 h,and the short-term potential difference drift is less than 0.02 m V.It shows that the structure of the composite electrode after the addition of carbon fiber and silver bromide is strengthened,and the service life is significantly prolonged. |
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