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《机械活化辅助多元醇法合成锂离子正极材料LiFePO_4.pdf》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、物理化学学~(WuliHuaxueXuebao)MayActaP.一Chim..2012,28(5),1183—1188ll83[Article]doi:10.3866/PKU.WHXB201202221www.whxb.pku.edu.cn机械活化辅助多元醇法合成锂离子正极材料LiFePO4曹雁冰,段建国’姜锋胡国荣’彭忠东杜柯’(。中南大学冶金科学与工程学院,长沙410083;中南大学材料科学与工程学院,长沙410083)摘要:以LiHPO和还原铁粉为原料,通过机械液相活化法获得了棒状形貌的[F
2、e。(PO)z·8HzO+Li。PO】前驱体,然后在三甘醇(TEG)介质中采用多元醇工艺制备了LiFePO材料.为提高其电导率,以聚乙烯醇(PVA)为碳源,对纯相LiFePO进行碳包覆改性.通过X射线衍射(XRO)、扫描电镜(SEM)、透射电镜(TEM)、恒电流充放电和电化学阻抗谱(EIS)等测试方法对制备的材料进行了表征.结果表明:采用机械活化辅助多元醇法可在低温下合成结晶良好的LiFePO,碳包覆改性的LiFePO/C材料导电性能得到改善,电荷转移阻抗减小,1C、2C倍率下放电容比量分别为139
3、.8、129.5mAh·g~,具有良好的倍率性能和循环稳定性.关键词:正极材料:LiFePO:机械活化:多元醇法:碳包覆中图分类号:0646SynthesisofLiFeP04CathodeMaterialsbyMechanical-Activation-AssistedPolyolProcessingCAOYan—Bing,’DUANJian—Guo’JIANGFengHUGuo-RongPENGZhong·Dong’DUKe’(SchoolofMetallurgicalScienceandEng
4、ineering,CentralSouthUniversity,Changsha410083,PRChinaSchoolofMaterialsScienceandEngineering,CentralSouthUniversity,Changsha410083,PR.China)Abstract:AlOW.temperatureapproachforeficientpreparationofLiFePOwasdeveloped.Therod-shaped【Fe~(PO,)2·8H2O+Li3PO4】
5、precursorwasprepared,usingamechanochemicalliquid-phaseactivationtechnique.fr0mLiH2PO4andreductionironpowder.PureLiFePO4wasthensynthesizedinboilingtetra(ethyleneglyco1)(TEG)bypolyolprocessingwiththeas—preparedprecursor.Inordertoimprovetheelectricalcondu
6、ctivity,carboncoatingofthepureLiFePO4wascarriedout,usingpoly(vinylalcohol1(PVA1asthecarbonsource.TheproductswerecharacterizedbyX—raydifraction(XRD),scanningelectronmicroscopy(SEM),transmissionelectronmicroscopy(TEM),galvanostaticcharge—dischargetestand
7、electrochemicaIimpedancespectroscopy(EIS).Theresultsshowthatwell-crystallizedLiFePOwassuccessfullysynthesizedbypolyolprocessingatlowtemperature.CarboncoatingsignificantlyimprovestheconductivepropertiesofLiFePO4andreducescharge-transferimpedance.Theobta
8、inedLiFePO4/Ccompositedeliversspecificdischargecapacitiesof139.8and129.5mAh·q。at1Cand2Crates,respectively,displayinggoodcyclingperformanceandratecapability.KeyWords:CathodeMaterial,LiFePO4:Mechanicalactivation;Polyolprocessing;Carboncoa
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