本文選題：金屬鋰電池　切入點(diǎn)：鋰負(fù)極　出處：《中國科學(xué)院大學(xué)(中國科學(xué)院物理研究所)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：金屬鋰由于其極高的理論容量(ca.3860mAh/g,2060mAh/cm3)和極低的電極電勢(-3.045V相對于標(biāo)準(zhǔn)氫電極)而被用于鋰電池中。不可控的鋰枝晶生長,無限的體積膨脹和低的循環(huán)效率困擾了研究者們多年。最近由于Linda Nazar和Peter G.Bruce對Li-S,Li-O2電池的研究以及固態(tài)電解質(zhì)的最新進(jìn)展使得金屬鋰重新被重視。金屬鋰的改性有多種方法,如:在電解液中添加添加劑,3D集流體做骨架支撐,固態(tài)電解質(zhì)的機(jī)械壓制,金屬鋰的表面處理,使用鋰金屬合金,采用高鹽濃度電解液,目的是為了解決金屬鋰存在的問題,目前還沒有找到合適的方法。我們研究了孤立導(dǎo)體表面靜電平衡下的電場分布對鋰離子在液態(tài)電解液中沉積溶解動力學(xué)行為的影響,通過在金屬鋰表面制備大面積有序的結(jié)構(gòu)的方法對金屬鋰作改性處理,并用微加工的方法首次成功地在金屬鋰表面大面積地制備了具有六角密排的亞微米圓柱形孔洞結(jié)構(gòu),分為500nm,5um,50um三種孔徑。使用具有該結(jié)構(gòu)(pattern)的鋰負(fù)極裝配了CR2032扣式電池和三電極電池電池,采用不同體系電解液進(jìn)行電化學(xué)測試,將測試后的電池拆解出鋰負(fù)極清洗后采用SEM進(jìn)行形貌的觀察。鋰離子在金屬鋰表面的沉積和溶解受到微觀電場的調(diào)控,部分鋰離子在pattern的孔洞側(cè)沿電場最強(qiáng)處以金屬鋰的形式均勻沉積。此外,微觀結(jié)構(gòu)使電極的比表面積增大,使電極表面真實(shí)電流密度降低。一方面增大了鋰枝晶的形成時間τ,抑制鋰枝晶的生成,另一方面降低了電極的極化。采用三電極電池殼分析了鋰離子進(jìn)入孔洞的量,對三電極電池做一周沉積后,在掃描電鏡下找出其中多個任意區(qū)域做大數(shù)據(jù)統(tǒng)計可以得到鋰離子在孔洞內(nèi)沉積的半定量結(jié)果。
[Abstract]:Lithium metal has been used in lithium batteries because of its extremely high theoretical capacity (Ca. 3860 mAh/ g) and extremely low electrode potential (-3.045V relative to the standard hydrogen electrode). The infinite volume expansion and low cycle efficiency have puzzled researchers for many years. Recently, due to the research of Li-Su Li-O2 batteries by Linda Nazar and Peter G. Bruce and the recent development of solid electrolyte, lithium metal has been revalued. There are many ways to modify lithium metal. For example, adding additives such as 3D fluid collection to electrolyte as skeleton support, mechanical compaction of solid electrolyte, surface treatment of lithium metal, use of lithium metal alloy, use of electrolyte with high concentration of salt to solve the problem of metal lithium, At present, no suitable method has been found. We have studied the effect of electric field distribution on the deposition and dissolution kinetics of lithium ions in liquid electrolyte under electrostatic equilibrium on the surface of isolated conductors. Lithium metal was modified by preparing large area ordered structure on the surface of lithium metal. For the first time, the submicron cylindrical structure with hexagonal compact arrangement was successfully fabricated on the surface of lithium metal by micromachining. The lithium anode with this structure is used to assemble the CR2032 button battery and the three-electrode battery, and the electrochemical tests are carried out using different electrolyte solutions. The morphology of lithium anode was observed by SEM after the battery was disassembled out of the tested battery. The deposition and dissolution of lithium ion on the surface of lithium metal were controlled by microelectric field. Some lithium ions are deposited uniformly in the form of lithium in the form of metal lithium along the hole side of pattern, and the microstructure increases the specific surface area of the electrode. The real current density on the electrode surface is decreased. On the one hand, the formation time of lithium dendrite is increased, and the formation of lithium dendrite is inhibited, on the other hand, the polarization of the electrode is reduced. After one week deposition of the three-electrode battery, the semi-quantitative results of lithium ion deposition in the pore can be obtained by using big data statistics in several arbitrary areas under scanning electron microscope.
【學(xué)位授予單位】：中國科學(xué)院大學(xué)(中國科學(xué)院物理研究所)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG146.26;TM912

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