本文主要研究内容
作者肖明军(2019)在《Co/Co3O4/氮掺杂碳复合材料的制备及电化学性能研究》一文中研究指出:Co3O4作为锂离子电池负极材料,具有理论比容量高(896 mAh g-1)、化学性质稳定、安全性能较好等优点,但是Co3O4同时具有导电性差、不可逆容量大、体积效应严重等缺点。研究表明,通过纳米化、碳复合、形貌控制等方法可以改善Co3O4的电化学性能。其中碳复合是最具前景的方法,碳复合不仅可以促进电子的传输,还可以缓解体积效应造成的粉碎、脱落现象,表现出优良的均一性、电化学性能、动力学性能。本文采用离子液体作为碳源,制备了氮掺杂碳(NDC)包覆的Co/NDC、Co3O4/NDC、Co/Co3O4/NDC等系列复合材料,利用XRD、Raman、SEM、TEM等技术对其结构和形貌进行表征,采用恒电流充放电法、循环伏安法、交流阻抗等测试材料的电化学性能,并探讨材料的结构和形貌特点与电化学性能之间的关系。主要研究内容如下:(1)以1-丁基-3-甲基咪唑二腈胺盐作为碳源,采用一步法制备Co/NDC复合材料。TEM测试表明钴纳米颗粒均匀嵌在NDC材料中,并形成核壳结构。恒电流充放电测试结果表明,Co/NDC复合材料在0.1 C下经过60个循环后可逆容量为657 mAh g-1,明显高于NDC材料的393 mAh g-1。交流阻抗测试表明Co/NDC复合材料相比NDC材料具有较小的电荷传输阻抗。Co/NDC复合材料优良的电化学性能归因于钴纳米颗粒增强了充放电过程中电子的传输和锂离子的迁移。将Co/NDC复合材料在空气中进行氧化,制备了Co3O4/NDC复合材料。SEM和TEM测试表明NDC材料包覆在Co3O4颗粒表面。恒电流充放电测试结果表明,Co3O4/NDC复合材料在0.1 C下经过100个循环后可逆容量为1088 mAh g-1。100个循环后,Co3O4/NDC复合材料和纯Co3O4的SEM和交流阻抗被测试,结果表明NDC材料不仅降低了Co3O4电荷传输阻抗,而且还减缓了充放电过程中体积效应造成的结构破坏。(2)以1-已基-3-甲基咪唑二腈胺盐作为碳源,采用尿素均相沉淀法制备出前驱体,再经高温还原制备Co/NDC复合材料。TEM和SEM表明钴纳米颗粒均匀分散在NDC材料中,并且钴纳米颗粒周围形成一层洋葱形貌的氮掺杂碳材料。恒电流充放电测试结果表明,Co/NDC复合材料在0.5 C下850个循环后可逆容量为1322 mAh g-1,5 C下循环2400次仍保持可逆容量为436 mAh g-1。交流阻抗测试表明Co/NDC复合材料在不同循环次数下SEI膜阻抗变化规律。Co/NDC复合材料优良的电化学性能归因于钴纳米颗粒不仅增强导电性,而且还具有催化活性。通过控制氧化条件,将Co/NDC复合材料在空气中进行氧化,得到Co/Co3O4/NDC复合材料。TEM测试表明洋葱形貌的氮掺杂碳材料包覆着Co/Co3O4纳米颗粒,形成一种核中核结构。这种结构的复合材料有以下优点:(1)洋葱形貌的氮掺杂碳可以缓解体积效应,(2)金属钴可以进一步增强导电性,(3)形成的核中核可以进一步稳固结构,(4)电解液与活性材料具有良好接触,进而提高锂离子的传输效率。恒电流充放电测试结果表明,Co/Co3O4/NDC复合材料展现出优良的倍率性能(5 C和10 C下循环1500次,可逆容量分别为790 mAh g-1和304 mAh g-1)。(3)以1-已基-3-甲基咪唑二腈胺盐作为碳源制备的Co/NDC复合材料,经盐酸溶液溶解去除金属内核,得到中空结构的氮掺杂洋葱碳(NDPOC)材料。SEM和TEM测试表明该氮掺杂碳材料为中空结构,而且孔周围有一层洋葱形貌的氮掺杂碳材料。这种结构的氮掺杂碳材料具有以下优点:(1)中空结构可以缩短锂离子的传输距离,(2)洋葱的形貌可以减弱体积效应,缓解孔的破裂。恒电流充放电测试显示,NDPOC材料在0.1 C下循环50次仍保持了805 mAh g-1可逆容量,5 C下300个循环和10 C下500个循环后,可逆容量分别为306 mAh g-1和267 mAh g-1。交流阻抗测试不仅表明NDPOC材料具有较小的电荷传输阻抗,而且还进一步验证NDPOC材料具有优良的循环稳定性(1个循环后,5个循环后,10个循环后,电荷传输阻抗基本一致)。(4)以1-已基-3-甲基咪唑二腈胺盐作为碳源,采用溶剂热法制备了Co3O4/NDC复合材料。TEM测试表明无定形氮掺杂碳材料均匀分布在Co3O4纳米颗粒周围,这些无定形碳在Co3O4周围形成导电网络,不但能提高颗粒之间的电子传输而且能缓解充放电过程造成的体积效应,从而提高电化学性能。恒电流充放电测试显示,Co3O4/NDC复合材料在0.1 C时,首次放电比容量为1101 mAh g-1,首次充电比容量为879 mAh g-1,首次库伦效率为74.86%,50个循环后可逆容量为1056 mAh g-1。交流阻抗测试结果表明碳复合可以有效降低电荷传输阻抗。Co3O4/NDC复合材料良好的电化学性能归功于NDC材料与Co3O4颗粒之间形成紧密的包覆,有利于提高Co3O4的导电性以及缓解充放电过程中产生的体积效应。
Abstract
Co3O4zuo wei li li zi dian chi fu ji cai liao ,ju you li lun bi rong liang gao (896 mAh g-1)、hua xue xing zhi wen ding 、an quan xing neng jiao hao deng you dian ,dan shi Co3O4tong shi ju you dao dian xing cha 、bu ke ni rong liang da 、ti ji xiao ying yan chong deng que dian 。yan jiu biao ming ,tong guo na mi hua 、tan fu ge 、xing mao kong zhi deng fang fa ke yi gai shan Co3O4de dian hua xue xing neng 。ji zhong tan fu ge shi zui ju qian jing de fang fa ,tan fu ge bu jin ke yi cu jin dian zi de chuan shu ,hai ke yi huan jie ti ji xiao ying zao cheng de fen sui 、tuo la xian xiang ,biao xian chu you liang de jun yi xing 、dian hua xue xing neng 、dong li xue xing neng 。ben wen cai yong li zi ye ti zuo wei tan yuan ,zhi bei le dan can za tan (NDC)bao fu de Co/NDC、Co3O4/NDC、Co/Co3O4/NDCdeng ji lie fu ge cai liao ,li yong XRD、Raman、SEM、TEMdeng ji shu dui ji jie gou he xing mao jin hang biao zheng ,cai yong heng dian liu chong fang dian fa 、xun huan fu an fa 、jiao liu zu kang deng ce shi cai liao de dian hua xue xing neng ,bing tan tao cai liao de jie gou he xing mao te dian yu dian hua xue xing neng zhi jian de guan ji 。zhu yao yan jiu nei rong ru xia :(1)yi 1-ding ji -3-jia ji mi zuo er jing an yan zuo wei tan yuan ,cai yong yi bu fa zhi bei Co/NDCfu ge cai liao 。TEMce shi biao ming gu na mi ke li jun yun qian zai NDCcai liao zhong ,bing xing cheng he ke jie gou 。heng dian liu chong fang dian ce shi jie guo biao ming ,Co/NDCfu ge cai liao zai 0.1 Cxia jing guo 60ge xun huan hou ke ni rong liang wei 657 mAh g-1,ming xian gao yu NDCcai liao de 393 mAh g-1。jiao liu zu kang ce shi biao ming Co/NDCfu ge cai liao xiang bi NDCcai liao ju you jiao xiao de dian he chuan shu zu kang 。Co/NDCfu ge cai liao you liang de dian hua xue xing neng gui yin yu gu na mi ke li zeng jiang le chong fang dian guo cheng zhong dian zi de chuan shu he li li zi de qian yi 。jiang Co/NDCfu ge cai liao zai kong qi zhong jin hang yang hua ,zhi bei le Co3O4/NDCfu ge cai liao 。SEMhe TEMce shi biao ming NDCcai liao bao fu zai Co3O4ke li biao mian 。heng dian liu chong fang dian ce shi jie guo biao ming ,Co3O4/NDCfu ge cai liao zai 0.1 Cxia jing guo 100ge xun huan hou ke ni rong liang wei 1088 mAh g-1。100ge xun huan hou ,Co3O4/NDCfu ge cai liao he chun Co3O4de SEMhe jiao liu zu kang bei ce shi ,jie guo biao ming NDCcai liao bu jin jiang di le Co3O4dian he chuan shu zu kang ,er ju hai jian huan le chong fang dian guo cheng zhong ti ji xiao ying zao cheng de jie gou po huai 。(2)yi 1-yi ji -3-jia ji mi zuo er jing an yan zuo wei tan yuan ,cai yong niao su jun xiang chen dian fa zhi bei chu qian qu ti ,zai jing gao wen hai yuan zhi bei Co/NDCfu ge cai liao 。TEMhe SEMbiao ming gu na mi ke li jun yun fen san zai NDCcai liao zhong ,bing ju gu na mi ke li zhou wei xing cheng yi ceng xiang cong xing mao de dan can za tan cai liao 。heng dian liu chong fang dian ce shi jie guo biao ming ,Co/NDCfu ge cai liao zai 0.5 Cxia 850ge xun huan hou ke ni rong liang wei 1322 mAh g-1,5 Cxia xun huan 2400ci reng bao chi ke ni rong liang wei 436 mAh g-1。jiao liu zu kang ce shi biao ming Co/NDCfu ge cai liao zai bu tong xun huan ci shu xia SEImo zu kang bian hua gui lv 。Co/NDCfu ge cai liao you liang de dian hua xue xing neng gui yin yu gu na mi ke li bu jin zeng jiang dao dian xing ,er ju hai ju you cui hua huo xing 。tong guo kong zhi yang hua tiao jian ,jiang Co/NDCfu ge cai liao zai kong qi zhong jin hang yang hua ,de dao Co/Co3O4/NDCfu ge cai liao 。TEMce shi biao ming xiang cong xing mao de dan can za tan cai liao bao fu zhao Co/Co3O4na mi ke li ,xing cheng yi chong he zhong he jie gou 。zhe chong jie gou de fu ge cai liao you yi xia you dian :(1)xiang cong xing mao de dan can za tan ke yi huan jie ti ji xiao ying ,(2)jin shu gu ke yi jin yi bu zeng jiang dao dian xing ,(3)xing cheng de he zhong he ke yi jin yi bu wen gu jie gou ,(4)dian jie ye yu huo xing cai liao ju you liang hao jie chu ,jin er di gao li li zi de chuan shu xiao lv 。heng dian liu chong fang dian ce shi jie guo biao ming ,Co/Co3O4/NDCfu ge cai liao zhan xian chu you liang de bei lv xing neng (5 Che 10 Cxia xun huan 1500ci ,ke ni rong liang fen bie wei 790 mAh g-1he 304 mAh g-1)。(3)yi 1-yi ji -3-jia ji mi zuo er jing an yan zuo wei tan yuan zhi bei de Co/NDCfu ge cai liao ,jing yan suan rong ye rong jie qu chu jin shu nei he ,de dao zhong kong jie gou de dan can za xiang cong tan (NDPOC)cai liao 。SEMhe TEMce shi biao ming gai dan can za tan cai liao wei zhong kong jie gou ,er ju kong zhou wei you yi ceng xiang cong xing mao de dan can za tan cai liao 。zhe chong jie gou de dan can za tan cai liao ju you yi xia you dian :(1)zhong kong jie gou ke yi su duan li li zi de chuan shu ju li ,(2)xiang cong de xing mao ke yi jian ruo ti ji xiao ying ,huan jie kong de po lie 。heng dian liu chong fang dian ce shi xian shi ,NDPOCcai liao zai 0.1 Cxia xun huan 50ci reng bao chi le 805 mAh g-1ke ni rong liang ,5 Cxia 300ge xun huan he 10 Cxia 500ge xun huan hou ,ke ni rong liang fen bie wei 306 mAh g-1he 267 mAh g-1。jiao liu zu kang ce shi bu jin biao ming NDPOCcai liao ju you jiao xiao de dian he chuan shu zu kang ,er ju hai jin yi bu yan zheng NDPOCcai liao ju you you liang de xun huan wen ding xing (1ge xun huan hou ,5ge xun huan hou ,10ge xun huan hou ,dian he chuan shu zu kang ji ben yi zhi )。(4)yi 1-yi ji -3-jia ji mi zuo er jing an yan zuo wei tan yuan ,cai yong rong ji re fa zhi bei le Co3O4/NDCfu ge cai liao 。TEMce shi biao ming mo ding xing dan can za tan cai liao jun yun fen bu zai Co3O4na mi ke li zhou wei ,zhe xie mo ding xing tan zai Co3O4zhou wei xing cheng dao dian wang lao ,bu dan neng di gao ke li zhi jian de dian zi chuan shu er ju neng huan jie chong fang dian guo cheng zao cheng de ti ji xiao ying ,cong er di gao dian hua xue xing neng 。heng dian liu chong fang dian ce shi xian shi ,Co3O4/NDCfu ge cai liao zai 0.1 Cshi ,shou ci fang dian bi rong liang wei 1101 mAh g-1,shou ci chong dian bi rong liang wei 879 mAh g-1,shou ci ku lun xiao lv wei 74.86%,50ge xun huan hou ke ni rong liang wei 1056 mAh g-1。jiao liu zu kang ce shi jie guo biao ming tan fu ge ke yi you xiao jiang di dian he chuan shu zu kang 。Co3O4/NDCfu ge cai liao liang hao de dian hua xue xing neng gui gong yu NDCcai liao yu Co3O4ke li zhi jian xing cheng jin mi de bao fu ,you li yu di gao Co3O4de dao dian xing yi ji huan jie chong fang dian guo cheng zhong chan sheng de ti ji xiao ying 。
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论文作者分别是来自兰州理工大学的肖明军,发表于刊物兰州理工大学2019-07-18论文,是一篇关于钴氧化物论文,氮掺杂碳论文,负极材料论文,锂离子电池论文,兰州理工大学2019-07-18论文的文章。本文可供学术参考使用,各位学者可以免费参考阅读下载,文章观点不代表本站观点,资料来自兰州理工大学2019-07-18论文网站,若本站收录的文献无意侵犯了您的著作版权,请联系我们删除。
标签:钴氧化物论文; 氮掺杂碳论文; 负极材料论文; 锂离子电池论文; 兰州理工大学2019-07-18论文;