本文選題：鋰硫電池 + C納米纖維無紡布��； 參考：《江蘇大學(xué)》2017年碩士論文

【摘要】：由于能源消耗帶來的環(huán)境問題,人們對(duì)高能量電池需求日漸增加。鋰硫電池因其能量密度高(2600 Wh kg~(-1))成為研究熱潮。但其自身不足減緩了鋰硫電池的商業(yè)化進(jìn)程,比如硫和最終放電產(chǎn)物的低電導(dǎo)性、循環(huán)過程中正極的體積膨脹效應(yīng)以及長鏈多硫化物的“穿梭效應(yīng)”,這些都造成了硫正極活性物質(zhì)的損耗�；钚晕镔|(zhì)低利用率影響其電化學(xué)性能,制約電池實(shí)際應(yīng)用化進(jìn)程。針對(duì)上述存在問題,本學(xué)位論文主要開展了電池新型結(jié)構(gòu)設(shè)計(jì)-插層改性研究。擬以高負(fù)載導(dǎo)電炭黑BP2000/硫(W_t=70%)復(fù)合電極為研究對(duì)象,通過一步靜電紡絲法制備碳(C)納米纖維、氧化鋁/碳(Al_2O_3/C)復(fù)合納米纖維和鎳/碳(Ni/C)復(fù)合納米纖維無紡布,并探究了不同煅燒溫度和鋁(Al)鹽、鎳(Ni)鹽添加量制備的復(fù)合納米纖維無紡布在鋰硫電池中的應(yīng)用及對(duì)其電化學(xué)性能的影響。主要研究結(jié)果具體如下:采用簡便的一步靜電紡絲法制備了C納米纖維無紡布,同時(shí)探究不同煅燒溫度對(duì)其作為功能性插層應(yīng)用在電池中及對(duì)其電化學(xué)性能的影響。C納米纖維無紡布功能性插層改性的鋰硫電池在容量利用率、可逆性和循環(huán)倍率性能方面皆表現(xiàn)出了優(yōu)異的性能。在1C倍率下不同煅燒溫度的C納米纖維無紡布插層改性電池,循環(huán)200圈后放電比容量都仍然保持在760 mAh g~(-1)以上,明顯優(yōu)于不加插層的鋰硫電池(在0.5C倍率下循環(huán)200圈,僅有260 mAh g~(-1))。電性能的提高得益于C納米纖維無紡布功能性插層提供的良好的三維導(dǎo)電網(wǎng)絡(luò)結(jié)構(gòu),在充放電過程中減少了多硫化物的遷移穿梭現(xiàn)象。采用一步靜電紡絲法制備了不同煅燒溫度和Al鹽添加量的Al_2O_3/C復(fù)合納米纖維無紡布,并研究其作為功能性插層對(duì)鋰硫電池電化學(xué)性能的影響。研究結(jié)果表明,Al鹽添加量為1g的復(fù)合納米纖維無紡布插層改性電池在900℃時(shí)表現(xiàn)出較好的循環(huán)性能,在1 C倍率下初始放電容量為1360 mAh g~(-1),循環(huán)200圈仍有近1000 mAh g~(-1)的放電比容量,且優(yōu)于同溫度下的C納米纖維無紡布插層改性(1C倍率下循環(huán)200圈放電比容量在760 mAh g~(-1));且倍率性能亦明顯優(yōu)于C納米纖維無紡布插層改性。研究結(jié)果表明Al_2O_3/C復(fù)合納米纖維中的極性金屬-氧鍵可有效抑制多硫化物的穿梭。采用靜電紡絲法制備了Ni/C復(fù)合納米纖維無紡布。研究了不同煅燒溫度和Ni鹽添加量對(duì)鋰硫電池電化學(xué)性能的影響。研究發(fā)現(xiàn)Ni鹽添加量為1g的復(fù)合納米纖維在900℃時(shí)表現(xiàn)出優(yōu)異的循環(huán)性能。在1 C倍率下初始放電容量為1062mAh g~(-1),循環(huán)200圈后保持910 mAh g~(-1)的穩(wěn)定放電比容量。即使在2 C倍率下,仍然保持695 mAh g~(-1)的放電比容量。研究結(jié)果表明Ni/C復(fù)合納米纖維無紡布可作為新的二次集流體,為活性物質(zhì)提供良好的電子傳輸通道,從而改善鋰硫電池的循環(huán)和倍率性能。同時(shí)其多孔網(wǎng)絡(luò)結(jié)構(gòu)能夠抑制多硫化物的擴(kuò)散。
[Abstract]:Due to the environmental problems caused by energy consumption, the demand for high energy batteries is increasing day by day. Lithium-sulfur battery has become a hot research subject because of its high energy density of 2600 Wh / kg ~ (-1). However, its shortcomings have slowed the commercialization of lithium-sulfur batteries, such as the low conductivity of sulfur and final discharge products, the volumetric expansion of positive electrodes during cycling and the "shuttle effect" of long-chain polysulfide. These results in the loss of sulfur positive active substances. The low utilization rate of active substances affects their electrochemical performance and restricts the practical application of batteries. In order to solve the above problems, this dissertation focuses on the design of new battery structure-intercalation modification. In this paper, the composite electrode of high load conductive carbon black BP2000/ T / W / T 70) was used as the research object. The carbon fiber was prepared by one step electrostatic spinning method. The composite nanofibers of alumina / carbon Al _ 2O _ 3 / C _ 2O _ 3 / Ni / C / Ni / C / C composite nanofibers were prepared. The application of composite nanofiber nonwoven fabric with different calcination temperature, Al _ 2O _ 3 and Ni _ (2) salt in lithium sulfur battery and its effect on electrochemical performance were investigated. The main results are as follows: C nanofiber non-woven fabric was prepared by a simple one-step electrostatic spinning method. At the same time, the effect of different calcination temperature on the application of functional intercalation in the battery and on its electrochemical performance. The capacity utilization of the functional intercalated lithium sulfur battery modified by functional intercalation of carbon nanofiber nonwoven fabric was investigated. Both the reversibility and the cyclic rate performance show excellent performance. The discharge specific capacity of C nanofiber non-woven intercalated modified battery with different calcination temperature at 1C ratio is still above 760 mAh / g / 1 after cycle 200th cycle, which is obviously superior to that of lithium sulfur cell without intercalation (circulating 200 cycles at 0.5C ratio). Only 260 mAh. The improvement of electrical properties is due to the good three-dimensional conductive network structure provided by the functional intercalation of C nanofiber nonwoven fabric, which reduces the migration and shuttle phenomenon of polysulfide during charging and discharging. The non-woven Al_2O_3/C composite nanofibers with different calcination temperature and Al salt content were prepared by one-step electrostatic spinning method. The effect of the functional intercalation on the electrochemical performance of lithium sulfur battery was studied. The results show that the composite nano-fiber non-woven intercalation modified battery with 1 g Al salt has good cycling performance at 900 鈩，

本文編號(hào)：1836120