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ID:28571248
大小:8.26 MB
页数:129页
时间:2018-12-11
《niohlt2gt电极纳米添加剂对mhni电池高倍率性能影响的作用机理》由会员上传分享,免费在线阅读,更多相关内容在应用文档-天天文库。
1、浙江大学博士学位论文摘要与耳录采用合适的反应温度和葡萄糖溶液浓度,通过水热反应实现了对球形p·Ni(OH)2表面非晶态纳米碳修饰。电化学测试表明,在O.2C和lC的低中倍率下,虽然表面碳修饰的B.Ni(OrI)2电极电化学循环性能更稳定,但电极活性物质球形13-Ni(Onh的利用率约为87%,比普通Ni(OH)2电极减少约10%。但在3C倍率放电条件下,表面碳修饰的B.Ni(OH)2电极在循环30周期后放电容量基本没有变化,且放电电压高出普通Ni(OH)2电极约30mV。此外,为了更好的实现碳修饰13-N
2、i(OH:h电极的高倍率性能,应适当添加约6wt.%CoO。采用湿化学沉淀法在醇一水体系中制备了结晶良好、粒度约20_30am、振实密度为1.7g/ml的球形a-Ni(OI-lh,并研究讨论了络合剂与陈化时间对a-Ni(01Th组织结构的影响。含10wt.%a-Ni(OH)2的复相I]/a-Ni(OI-Ih粉体,振实密度高达2.41g/ml。对D旭.Ni(OH)2复相电极材料电化学性能的研究发现,纳米a-Ni(OHh的电化学活性高于D—Ni(OH:h。纳米球形a-Ni(OHh的添加提高了电极的放电比容量、
3、放电电压和循环寿命。纳米a-Ni(OH)2的最佳含量为10wt.%,添加过多的纳米a-Ni(OHh会恶化电极的电化学性能。关键词:镍氢电池;IB-Ni(OHh电极;高倍率性能;添加剂;纳米CoO;碳纳米管;表面修饰:纳米a-Ni(OH)2n浙江大学博士学位论文摘要与目录AbstractAsoneofthemostwidelyusedrechargeablebaReries,nickel·metalhydride(MH/Ni)batteries哦requiredtoimprovethehighpowerch
4、aracteristicsconsideringapplicationforelectricvehicles.ThehighpowerperformanceofMH/NibatteryisaffectedstronglybythepositiveelectrodebecauseofthepoorconductivityoftheactivematerialI$-Ni(OI如.Inthiswork,nanosizedadditivessuchasnanoscaleCoO,multiwalledcarbonn
5、anotubes(CNTs),nanoscalea-Ui(OHhandsurface—modifiedamorphousnanosizedcarbonweresynthesizedasadditivesfortheNi(OH)2electrodes.ThemorphologiesandstructuresofthenanoscaleadditiveswereeharaeteredbyXRD.SEMandTEM.Theinfluencesofthesenanosizedadditivesontheovera
6、llperformanceofNi/MHbatteries,especiallythehigh—ratecapability,wereevaluatedbythemeansofelectrochemicalmeasurements,includingelectrochemicalimpedancespectrum,cyclicvoltammetryandcharge—dischargecycling.COC03nanorodsasprecursorweresynthesizedbyprecipitatio
7、nmethodandshortrod-likenanoscaleCoOwaspreparedbydecomposingCOC03invacuum.Comparedwiththeelectrodeswithusualsub-micronCoO,theelectrochemicalmeasurementsindicatethattheelectrodeswithnanoscaleCoOexhibitlowerOhmimpedanceandthelowerelectrochemicalreactionimped
8、ance,narrowerredoxpotentialspaceandhighreactionpotential.ThespecificcapacityoftheelectrodeswitIInanosealeCoOisupto283mAh/g,whichisclosetothetheoreticalspecificcapacityof13-Ni(OH)2.ThesealedMH/Nibakerieswithnanoscale
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