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Highly Conductive Polymer Coated H2Ti12O25 Anode Material With An In-Suit Technique And Its Electrochemical Performance

Posted on:2019-11-11Degree:MasterType:Thesis
Country:ChinaCandidate:J J LiangFull Text:PDF
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Titanium-based materials have the advantages of good cycle stability,high safety factor,and environmental friendliness compared with traditional carbon-based materials.Among them,the high-voltage anode material H2Ti12O25 has gradually attracted more attention due to its high theoretical capacity and good cycle stability.However,the intrinsic low lithium ion diffusion coefficient and the conductivity for H2Ti12O25,seriously restrict its practicality and commercialization.In this paper,highly conductive polymers?PANI or PEDOT?was coated on the surface of H2Ti12O25,using in-situ polymerization,respectively.And the effect of PANI coating layer on the electrochemical performance of H2Ti12O255 were also analysized.1.H2Ti12O255 submicron particles were synthesized by mean of milling assisted soft-chemistry method,XRD characterization confirmed that the product was pure-phase H2Ti12O25.2.PANI coated H2Ti12O255 was prepared by in-situ polymerization of polyaniline doped with a single inorganic hydrochloric acid.The discharge capacity and rate performance of H2Ti12O255 can be effectively improved by coating a polyaniline layer.When the coating content is 2 wt%?denoted as HTO/P2?,the initial discharge capacity of HTO/P2 at 1C is 253.8 mAh·g-1,and afte 200 cycles,the capacity can still retain 151 mAhg-1 with a capacity retention rate of 94.2%.Even at a high discharge rate of 20C,a discharge specific capacity of 76 mAhg-1 still can be obtained.3.H2Ti12O25 was also modified by PANI layer using in-situ polymerization with sulfosalicylic acid and hydrochloric acid co-dopping.Polyaniline co-doped with mixed-acid is more dispersible and more conductive.The above synthiszed sample HTO/P22 has higher discharge capacity and better rate performance,and its specific discharge capacity at 1C was up to 175.4 mAhg-1 with a capacity retention rate of98.5%after 200 cycles.When discharged at 20C,a discharge specific capacity of 96.7mAhg-1 can still be obtained.4.H2Ti12O25 was coated by highly conductive polymer PEDOT using in-situ polymerization route.When the coating amount of PEDOT is 5 wt%?HTO/PE?,the discharge capacity and the rate performance of H2Ti12O25 can be significantly improved.After cycling 200 times at 1C,the discharge specific capacity of HTO/PE was 167 mAhg-1,whereas the 200-cycle capacity of HTO was only 109 mAhg-1.
Keywords/Search Tags:H2Ti12O25, Soft-chemical method, Conductive polymer coating, Electrochemical performance
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