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作者杜玲玉（2019）在《碳基纳米笼本征催化与限域协同促进的高性能锂硫电池正极材料的设计、性能及机制》一文中研究指出：锂硫电池具有能量密度高、成本低等突出优点,是最具应用前景的下一代二次电池体系之一。然而,锂硫电池的硫正极存在硫和放电产物硫化锂的导电性差、中间物种多硫化锂的溶解和穿梭效应显著、多硫化锂转化反应的动力学过程缓慢、循环过程中硫物种的体积变化大等问题,导致锂硫电池仍面临硫利用率低、容量衰减快、功率密度有限、面积硫载量与面积比容量低等挑战。本文拟从引入催化与限域协同促进作用的角度解决上述难题,基于氮掺杂、硫掺杂及氮磷共掺杂碳纳米笼设计构建出新型硫正极,开展电池性能及作用机制研究,旨在获得高性能锂硫电池正极材料。通过研究,取得了如下重要进展:1.以多功能氮掺杂碳纳米笼(hNCNC)作为硫载体和隔膜修饰层构建了高功率长寿命的锂硫电池。通过电催化实验和密度泛函理论计算,揭示了氮掺杂sp2碳具有高效催化转化多硫化锂的功能。将硫填充于hNCNC内腔,发挥纳米笼的物理限域、氮掺杂sp2碳的化学吸附及电催化转化的高效协同,再结合三维分级结构促进的快速电荷转移功能,实现了多硫化锂流畅的“吸附”-“转化”过程,有效地抑制了穿梭效应和极化效应,实现了高功率长寿命的电池性能。对于硫面积载量为0.8 mg cm-2的正极,在超高电流密度20 A g-1时比容量达到539 mAh g-1,在10 A g-1循环1000次后比容量仍保留438 mAh g-1,平均每圈衰减率为0.05%。当硫面积载量增加至3 mg cm-2时,在3 Ag-1下仍可获得605 mAh g-1的高比容量。该研究不仅揭示了氮掺杂sp2碳除公认的“化学吸附”功能之外的“催化转化”新功能,还展示了通过采用具有电催化活性的碳基载体来获得高功率长寿命锂硫电池的有效策略。2.利用异质原子掺杂碳化学吸附多硫化锂以抑制其扩散是改善锂硫电池性能的有效途径。然而,我们注意到硫掺杂碳对多硫化锂的吸附能力弱于于未掺杂碳,但仍然能增强电池性能。这表明硫掺杂碳对锂硫电池性能的增强机制不是源于化学吸附,尚有待深入研究。本文将硫包裹在硫掺杂碳纳米笼(S@hSCNC)中,作为正极材料构建的锂硫电池展现出优于未掺杂碳对应电池的性能。通过实验和理论计算揭示了硫掺杂碳对电池性能的增强机制:循环伏安测试结果中,S@hSCNC电池具有较高的还原起始电位和较低的氧化起始电位,证实了 hSCNC对多硫化锂转化反应具有催化作用,从而增强了反应动力学过程、提高了硫物种的转化效率。硫掺杂碳纳米笼集成了纳米笼的物理限域作用和硫掺杂碳的催化转化功能,协同促进了锂硫电池性能,在高电流密度10 A g-1循环600次后仍可释放528 mAh g-1的比容量。该研究为硫掺杂碳基载体的设计和性能优化提供了思想基础。3.提高硫面积载量是获得高能量密度锂硫电池的前提,然而随着电极厚度增加,电荷传输动力学与电化学反应动力学过程受到抑制,导致硫利用率降低、比容量下降,难以满足锂硫电池的应用要求。考虑到氮磷共掺杂碳对多硫化锂具有双重吸附与催化转化作用,本文在通过原位还原氧化石墨烯(GO)构筑高硫面积载量的自支撑整体电极的过程中引入氮磷共掺杂碳纳米笼(hNPCNC),制备出具有高硫面积载量的自支撑电极材料(S@hNPCNC@rGO),展示出独特优势:1)hNPCNC将硫限域在纳米笼内,通过协同吸附与催化功能有效促进多硫化锂的吸附与转化;2)rGO进一步阻挡多硫化锂流失,保证多硫化锂在三维网络结构内循环;3)多孔结构充当电解液储藏库,充分浸润活性材料,提高硫物种的利用率;4)不使用导电剂、粘结剂与集流体,简化了电极制备工艺,有利于提高全电池的能量密度。当硫面积载量为6 mg cm-2时,该电极在循环250次后仍保留4.2 mAh cm-2的高面积比容量,处于氮磷共掺杂碳基硫正极材料的领先水平,优于传统锂离子电池的性能,为推进锂硫电池实用化进程提供了新的思路。
Abstract
li liu dian chi ju you neng liang mi du gao 、cheng ben di deng tu chu you dian ,shi zui ju ying yong qian jing de xia yi dai er ci dian chi ti ji zhi yi 。ran er ,li liu dian chi de liu zheng ji cun zai liu he fang dian chan wu liu hua li de dao dian xing cha 、zhong jian wu chong duo liu hua li de rong jie he chuan suo xiao ying xian zhe 、duo liu hua li zhuai hua fan ying de dong li xue guo cheng huan man 、xun huan guo cheng zhong liu wu chong de ti ji bian hua da deng wen ti ,dao zhi li liu dian chi reng mian lin liu li yong lv di 、rong liang cui jian kuai 、gong lv mi du you xian 、mian ji liu zai liang yu mian ji bi rong liang di deng tiao zhan 。ben wen ni cong yin ru cui hua yu xian yu xie tong cu jin zuo yong de jiao du jie jue shang shu nan ti ,ji yu dan can za 、liu can za ji dan lin gong can za tan na mi long she ji gou jian chu xin xing liu zheng ji ,kai zhan dian chi xing neng ji zuo yong ji zhi yan jiu ,zhi zai huo de gao xing neng li liu dian chi zheng ji cai liao 。tong guo yan jiu ,qu de le ru xia chong yao jin zhan :1.yi duo gong neng dan can za tan na mi long (hNCNC)zuo wei liu zai ti he ge mo xiu shi ceng gou jian le gao gong lv chang shou ming de li liu dian chi 。tong guo dian cui hua shi yan he mi du fan han li lun ji suan ,jie shi le dan can za sp2tan ju you gao xiao cui hua zhuai hua duo liu hua li de gong neng 。jiang liu tian chong yu hNCNCnei qiang ,fa hui na mi long de wu li xian yu 、dan can za sp2tan de hua xue xi fu ji dian cui hua zhuai hua de gao xiao xie tong ,zai jie ge san wei fen ji jie gou cu jin de kuai su dian he zhuai yi gong neng ,shi xian le duo liu hua li liu chang de “xi fu ”-“zhuai hua ”guo cheng ,you xiao de yi zhi le chuan suo xiao ying he ji hua xiao ying ,shi xian le gao gong lv chang shou ming de dian chi xing neng 。dui yu liu mian ji zai liang wei 0.8 mg cm-2de zheng ji ,zai chao gao dian liu mi du 20 A g-1shi bi rong liang da dao 539 mAh g-1,zai 10 A g-1xun huan 1000ci hou bi rong liang reng bao liu 438 mAh g-1,ping jun mei juan cui jian lv wei 0.05%。dang liu mian ji zai liang zeng jia zhi 3 mg cm-2shi ,zai 3 Ag-1xia reng ke huo de 605 mAh g-1de gao bi rong liang 。gai yan jiu bu jin jie shi le dan can za sp2tan chu gong ren de “hua xue xi fu ”gong neng zhi wai de “cui hua zhuai hua ”xin gong neng ,hai zhan shi le tong guo cai yong ju you dian cui hua huo xing de tan ji zai ti lai huo de gao gong lv chang shou ming li liu dian chi de you xiao ce lve 。2.li yong yi zhi yuan zi can za tan hua xue xi fu duo liu hua li yi yi zhi ji kuo san shi gai shan li liu dian chi xing neng de you xiao tu jing 。ran er ,wo men zhu yi dao liu can za tan dui duo liu hua li de xi fu neng li ruo yu yu wei can za tan ,dan reng ran neng zeng jiang dian chi xing neng 。zhe biao ming liu can za tan dui li liu dian chi xing neng de zeng jiang ji zhi bu shi yuan yu hua xue xi fu ,shang you dai shen ru yan jiu 。ben wen jiang liu bao guo zai liu can za tan na mi long (S@hSCNC)zhong ,zuo wei zheng ji cai liao gou jian de li liu dian chi zhan xian chu you yu wei can za tan dui ying dian chi de xing neng 。tong guo shi yan he li lun ji suan jie shi le liu can za tan dui dian chi xing neng de zeng jiang ji zhi :xun huan fu an ce shi jie guo zhong ,S@hSCNCdian chi ju you jiao gao de hai yuan qi shi dian wei he jiao di de yang hua qi shi dian wei ,zheng shi le hSCNCdui duo liu hua li zhuai hua fan ying ju you cui hua zuo yong ,cong er zeng jiang le fan ying dong li xue guo cheng 、di gao le liu wu chong de zhuai hua xiao lv 。liu can za tan na mi long ji cheng le na mi long de wu li xian yu zuo yong he liu can za tan de cui hua zhuai hua gong neng ,xie tong cu jin le li liu dian chi xing neng ,zai gao dian liu mi du 10 A g-1xun huan 600ci hou reng ke shi fang 528 mAh g-1de bi rong liang 。gai yan jiu wei liu can za tan ji zai ti de she ji he xing neng you hua di gong le sai xiang ji chu 。3.di gao liu mian ji zai liang shi huo de gao neng liang mi du li liu dian chi de qian di ,ran er sui zhao dian ji hou du zeng jia ,dian he chuan shu dong li xue yu dian hua xue fan ying dong li xue guo cheng shou dao yi zhi ,dao zhi liu li yong lv jiang di 、bi rong liang xia jiang ,nan yi man zu li liu dian chi de ying yong yao qiu 。kao lv dao dan lin gong can za tan dui duo liu hua li ju you shuang chong xi fu yu cui hua zhuai hua zuo yong ,ben wen zai tong guo yuan wei hai yuan yang hua dan mo xi (GO)gou zhu gao liu mian ji zai liang de zi zhi cheng zheng ti dian ji de guo cheng zhong yin ru dan lin gong can za tan na mi long (hNPCNC),zhi bei chu ju you gao liu mian ji zai liang de zi zhi cheng dian ji cai liao (S@hNPCNC@rGO),zhan shi chu du te you shi :1)hNPCNCjiang liu xian yu zai na mi long nei ,tong guo xie tong xi fu yu cui hua gong neng you xiao cu jin duo liu hua li de xi fu yu zhuai hua ;2)rGOjin yi bu zu dang duo liu hua li liu shi ,bao zheng duo liu hua li zai san wei wang lao jie gou nei xun huan ;3)duo kong jie gou chong dang dian jie ye chu cang ku ,chong fen jin run huo xing cai liao ,di gao liu wu chong de li yong lv ;4)bu shi yong dao dian ji 、nian jie ji yu ji liu ti ,jian hua le dian ji zhi bei gong yi ,you li yu di gao quan dian chi de neng liang mi du 。dang liu mian ji zai liang wei 6 mg cm-2shi ,gai dian ji zai xun huan 250ci hou reng bao liu 4.2 mAh cm-2de gao mian ji bi rong liang ,chu yu dan lin gong can za tan ji liu zheng ji cai liao de ling xian shui ping ,you yu chuan tong li li zi dian chi de xing neng ,wei tui jin li liu dian chi shi yong hua jin cheng di gong le xin de sai lu 。
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论文作者分别是来自南京大学的杜玲玉，发表于刊物南京大学2019-05-27论文，是一篇关于锂硫电池论文,碳基纳米笼论文,电催化剂论文,限域论文,化学吸附论文,调控机制论文,南京大学2019-05-27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，资料来自南京大学2019-05-27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。
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