| Radical polymers are aliphatic or nonconjugated polymers bearing organic robust radicals as pendant groups per repeating unit.In the charge-discharge process of lithium ion secondary battery,whose positive active material is polymer radical,only exists the free radical unpaired electron gains and losses,there is no bond cleavage or generation,and no embedding or extraction of lithium ions.Therefore,compared to other lithium ion secondary battery,the radical polymer battery having excellent rate capability and excellent cycle stability.As the organic positive electrode material of a new lithium ion secondary battery,radical polymer is biodegradable,high energy density,abundant raw materials,cheap,non-toxic,and can optimize its physical and chemical properties by changing the composition and structure of the polymer or be blended with organic polymers,it has very broad application prospect.We synthesized precursor polymer PMTMP,through a solution polymerization method,and explores the monomer concentration and the amount of initiator on the yield.8.9 mmol MTMP monomer,10 mL of toluene,0.3%AIBN as initiator,at a temperature of 70℃and a nitrogen atmosphere for 48 hours to obtain a precursor polymer PMTMP the highest yield.While hydrogen peroxide as the oxidizing agent,sodium tungstate as catalyst,disodium ethylenediaminetetraacetate solution as a buffer,the polymer flooding PMTMP quantitatively is converted to free radical polymer of PTMA,by an oxidation reaction.Radical polymer PTMA,super-conductive carbon black(BP-2000),and polyvinylidene fluoride(PVDF)as a starting material are mingled in certain proportion to obtain PTMA/carbon black composite electrode,and test their electrochemical properties.When the radical polymer PTMA content of 50%,the electrical properties of the composite electrode is best,it has excellent redox reversibility,discharge capacity up to 102 mAh/g,close to the PTMA theoretical specific capacity 111 mA h/g,and has a stable platform for charging and discharging,after 100 charge-discharge cycles,discharge capacity only decay 5%.By using Hummers method,we prepared reduce graphene oxide(rGO),simultaneously,organic radical polymer PTMA as the active material,reduce graphene oxide as a conductive agent,polyvinylidene fluoride as a binder,these materials are mingled in certain proportion to obtain PTMA/rGO composite electrode,and test the electrochemical performance.There were two platforms during PTMA/rGO composite electrode charging and discharging process,in this process also took place second order reversible redox reaction,Respectively corresponding the N-O~-and N-O·,N-O·and⊕N=O mutual transformation.Discharge capacity up to 163 mA h/g,which is 147%of a single electron redox reaction theoretical specific capacity(111 mA h/g).And after 100 cycles,the discharge capacity fading by 14.2%,stable after discharge capacity of 140 mA h/g,still more than the theoretical specific capacity of PTMA/carbon black composite electrode.Based on stable free radical polymer,a new anode materials with excellent electrochemical performance was prepared. |
