Electromagnetic Shielding And Electrochemical Properties Of Porous Carbon Foams

With the extensive use of communication technology,electric vehicles,mechanical braking energy storage,new energy storage and other equipments,supercapacitors with high output power,long cycle life,fast charge and discharge,gradually show great advantages,then become a research hotspot.Plenty of electronic and electrical equipments have been widely used,resulting in a great deal of electromagnetic pollution.It has a negative effect on human's health,mechanical and electrical equipments.Such situation made it an urgent and hot topic for electromagnetic interference shielding(EMI).Current study aims for preparing porous carbon foams with both good electrochemical and EMI properties,overcoming traditionally individual performance research.Main results are as follows.1.Carbon foams derived from phenolic resin with different CNTs content were prepared.EMI properties improved remarkably,from 51.37 d B to 71.15 d B,with incorporating CNTs.Maximum of compressive strength is 10.14 MPa,increased by 201.8%to that of pure carbon foam.It was attributed by synergistic effect of CNT's fracture,pull-out from matrix,hindering early crack propagation,and forcing to close cracks.For the carbon foam derived from melamine,its specific capacitance was merely 14.8 F·g^-1under the current density of0.1 A·g^-1,and EMI efficiency was merely 5.14 d B.2.Electroless nickel plating has been made on the surface of two kinds of carbon foams.Results showed that properties of carbon foam derived from melamine were optimal,with 60min electroless plating in the condition of 100 W ultrasonic.Its specific capacitance was up to 130 F·g^-1,under the current density of 0.5 A·g^-1,and EMI efficiency was up to 70.55 d B,which both improved significantly.Faraday pseudo-capacitance reaction was introduced in the nickel plating layer.Abundant porous fibrous skeleton provided a large area for effective redox reaction.Such above two points explained improvement of specific capacitance.Nickel plating layer also increased conductivity of carbon foam,which contributed a lot to higher EMI efficiency.3.Ni₃S₂ as been synthesized in nickel plating layer by hydrothermal process,which is on the surface of two kinds of carbon foams.Results showed that electrochemical and EMI performance failed to improve.Although Ni₃S₂particles formed on the surface of nickel plating layer,while the electroless nickel layer remaining on the surface of carbon foam was nearly completely consumed.