本文選題：Reline離子液體 + Sn基合金��； 參考：《湘潭大學》2017年碩士論文

【摘要】：錫基負極材料有高理論比容量(994 mAh g-1)和安全性能好等優(yōu)點,在鋰電科研領(lǐng)域備受青睞。錫基負極材料的商業(yè)化應(yīng)用,需要解決循環(huán)穩(wěn)定性差這一難題。錫在嵌鋰的時候會發(fā)生較大的體積膨脹,隨著循環(huán)次數(shù)的增加,活性材料錫在嵌鋰時形成Li4.4Sn的量增多,體積膨脹也越嚴重,使電極材料的活性成分發(fā)生粉化和脫落,可逆比容量便會大幅度下降。本文以Reline離子液體為溶劑,運用操作時間短、環(huán)保的電化學沉積法,在銅箔上電沉積制備Sn基合金負極材料。運用SEM、EDS和XRD表征和分析合金材料的表面形貌、物相及組成,同時運用CV和恒流充放電測試電化學性能。對比探索了溶液中溶質(zhì)的配比、溶液中不同類型的溶質(zhì)、電沉積時間和電流密度對Sn基合金材料的電化學性能方面的影響,期望錫基材料的電化學性能得到改善,為此,在以下三個方面開展了研究工作。1.Reline離子液體中電化學沉積Sn-Co合金負極材料探討了溶液中溶質(zhì)的配比、溶液中不同的溶質(zhì)、電沉積時間和電流密度對Sn基合金材料的電化學性能方面的影響。結(jié)果表明,溶液中溶質(zhì)的配比為Sn2+:Co2+=1:1,電沉積時間和電流密度分別設(shè)為20 min和2 mA cm-2以及溶液中的溶質(zhì)都為硫酸鹽化合物的條件下,制得的Sn-Co合金負極材料表面存在許多納米級孔洞,表現(xiàn)出最好的電化學性能。0.2 C下首次放電比容量為874 mAh g-1,首次充電比容量為716 mAh g-1,60次循環(huán)后的充放電比容量分別為892 mAh g-1和912 mAh g-1,除首次外的60次循環(huán)庫侖效率都在97%以上,首次庫侖效率為81.9%。2.Reline離子液體中電化學沉積Sn-Ni合金負極材料探討了溶液中溶質(zhì)的配比以及溶液中不同的溶質(zhì)對Sn基合金薄膜電極電化學性能的影響。結(jié)果表明,溶液中溶質(zhì)的配比為Sn2+:Ni2+=2:1以及溶液中的溶質(zhì)都為硫酸鹽化合物的條件下,制得的Sn-Ni合金負極材料表面形貌較分散且存在氣孔,表現(xiàn)出最好的電化學性能。0.5 C下首次放電比容量為580 mAh g-1,160次循環(huán)后放電比容量為451 mAh g-1,除首次外的160次循環(huán)庫侖效率在97%以上。3.Reline離子液體中電化學沉積Sn-Co-Zn合金負極材料探討了沉積電流密度和溶液中溶質(zhì)的配比對Sn基合金材料的電化學性能方面的影響。結(jié)果表明,電沉積電流密度設(shè)置為20 mA cm-2,溶液中溶質(zhì)的配比為Sn2+:Co2+:Zn2+=2:1:2下電沉積的Sn-Co-Zn合金負極材料,有很特別的表面形貌,表面顆粒為“楊桃型類八面體”結(jié)構(gòu),0.5 C下首次放電比容量為666 mAh g-1,前58次循環(huán)后,達到最大的放電比容量為977 mAh g-1。首次庫侖效率為77.5%,除首次外的80次循環(huán)庫侖效率在97%以上,是電化學性能較好的材料。
[Abstract]:Tin based anode material has many advantages, such as high theoretical specific capacity (994 mAh g-1) and good safety performance, so it is very popular in the field of lithium electric research. The commercial application of tin-based anode materials needs to solve the problem of poor cyclic stability. With the increase of cycle times, the amount of Li4.4Sn formed by tin in lithium intercalation increases, and the volume expansion becomes more serious, which causes the active composition of the electrode material to be powdered and shedding. The reversible specific capacity will be greatly reduced. Sn-base alloy anode materials were prepared by electrodeposition on copper foil using Reline ionic liquid as solvent and electrochemical deposition method with short operating time and environmental protection. The surface morphology, phase and composition of the alloy were characterized and analyzed by means of SEM-EDS and XRD. The electrochemical properties of the alloy were measured by CV and constant current charge-discharge. The effects of solute ratio in solution, different types of solute in solution, electrodeposition time and current density on the electrochemical properties of Sn based alloy materials were compared and explored. The electrochemical properties of tin based alloy materials were expected to be improved. 1. Electrochemical deposition of Sn-Co alloy negative electrode materials in Reline ionic liquids the proportion of solutes in solution, different solutes in solution, The effects of electrodeposition time and current density on the electrochemical properties of Sn-based alloys. The results show that the ratio of solute in the solution is Sn2: CO2 / 1: 1, the electrodeposition time and current density are 20 min and 2 Ma cm-2, respectively, and the solute in the solution is sulfate compound. There are many nanoscale holes on the surface of the Sn-Co alloy negative electrode material. The first discharge specific capacity is 874 mAh g-1 at 0.2C, and the charge-discharge specific capacity is 892 mAh g -1 and 912 mAh g -1 after 60 cycles of 716 mAh g -1, respectively. The Coulomb efficiency of 60 cycles except for the first time is above 97%. The first Coulomb efficiency was electrochemical deposition of negative electrode material of Sn-Ni alloy in 81.9%.2.Reline ionic liquid. The effects of solute ratio in solution and different solutes in solution on electrochemical properties of Sn-based alloy thin film electrode were investigated. The results show that when the solute ratio is Sn2: Ni2 / 2: 1 and the solutes in the solution are sulfate compounds, the surface morphology of the Sn-Ni alloy anode material is dispersed and there are pores. The first discharge specific capacity is 580 mAh g-1160 cycles and the discharge specific capacity is 451 mAh g-1. The Coulomb efficiency of 160 cycles except for the first time is over 97%. 3. Electrochemical deposition of Sn-Co-Zn alloy negative in Reline ionic liquid. The effects of deposition current density and the ratio of solute in solution on the electrochemical properties of Sn based alloy were investigated. The results show that the electrodeposition current density is 20 Ma / cm ~ (-2) and the ratio of solute in the solution is Sn2: Co _ 2: Zn _ 2: Zn _ 2: 1: 2. The electrodeposition of Sn-Co-Zn alloy negative electrode material has a very special surface morphology. The initial discharge specific capacity of the surface particles is 666 mAh g-1 under the structure of "caramon-like octahedron" 0.5C, and the maximum discharge specific capacity is 977 mAh g-1 after the first 58 cycles. The first Coulomb efficiency is 77.5%, and the Coulomb efficiency of 80 cycles except for the first time is more than 97%, so it is a material with good electrochemical performance.
【學位授予單位】：湘潭大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O646;TM912

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本文編號：1830253