發(fā)布時間：2018-02-12 08:30

  本文關(guān)鍵詞： 金屬基負(fù)極材料 成核生長機理 儲能機理 鋰離子電池 鈉離子電池　出處：《常州大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：金屬基材料,由于其理論容量高,工作電壓低且平穩(wěn),制備工藝簡單等特點而成為一類極具潛力的負(fù)極材料。但其在循環(huán)過程中由于劇烈體積變化而帶來的電化學(xué)性能不穩(wěn)定,一直是阻礙其市場化的主要屏障。本論文致力于構(gòu)建具有穩(wěn)定電化學(xué)性能的二次電池用金屬基負(fù)極材料,利用基礎(chǔ)表征手段探索二次電池用金屬基負(fù)極材料的成核生長機理,分析反應(yīng)條件對其成分、結(jié)構(gòu)、形貌變化的影響規(guī)律,并結(jié)合各類電化學(xué)測試手段研究二次電池用金屬基負(fù)極材料的儲能機理,分析其成分、結(jié)構(gòu)、形貌的變化對材料電化學(xué)性的影響規(guī)律,從而獲得制備具有優(yōu)異電化學(xué)性能的金屬基負(fù)極材料的有效工藝。論文研究的金屬基負(fù)極材料可主要分為鋰離子電池用和鈉離子電池用兩個部分。1、對于鋰離子電池用金屬基負(fù)極材料,以錳基、鐵基和錳鐵二元金屬材料為主。(1)以過渡金屬Mn為基點,研究了材料成分、形貌的變化對其性能的影響。以錳鹽和氨水為主要反應(yīng)物,采用水熱法制備了尖晶石相的Mn_3O_4,材料呈現(xiàn)為表面帶有附晶的納米棒狀,由于材料具有較大的尺寸維度,且導(dǎo)電率較低,在充放電過程中,材料與電解液的接觸潤濕、離子/電子的擴散傳遞都不理想、材料的體積變化較為嚴(yán)重,這導(dǎo)致材料的電化學(xué)性能不理想。為解決這一問題,采用了引入還原氧化石墨烯支撐材料的方法,在維護(hù)材料結(jié)構(gòu)穩(wěn)定性和提高導(dǎo)電率的同時,分析了還原氧化石墨烯的加入對復(fù)合材料形貌尺寸變化的影響,研究了復(fù)合材料的成核生長機理、儲能及儲能改善機理,獲得了具有良好的循環(huán)穩(wěn)定性和倍率性能的Mn_3O_4/還原氧化石墨烯,其首次放電比容量高達(dá)897.2 mAh g~(-1),100次循環(huán)后,比容量也依然可以保持在450 mAh g~(-1)左右,是沒加入還原氧化石墨烯材料之前比容量的4倍。在研究中發(fā)現(xiàn),雖然Mn_3O_4/rGO的循環(huán)穩(wěn)定性得到了提升,但材料的首次庫倫效率依舊不理想,這直接導(dǎo)致復(fù)合材料的可逆容量還是偏低,因此,對材料的結(jié)構(gòu)進(jìn)行了重新設(shè)計,在復(fù)合材料的表面包裹了一層聚吡咯,以減少首次循環(huán)固體電解質(zhì)界面(SEI)膜形成時的容量損耗,首次庫倫效率幾乎得到了翻倍增長,同時,利用EIS等測試手段分析并掌握了聚吡咯層的作用機理。(2)利用鐵基金屬材料,研究了材料結(jié)構(gòu)的變化對其性能的影響。Fe_2O_3材料的理論容量要明顯高于Fe_3O_4,但實際測試容量卻往往較低。同采用水熱法制備以上兩種鐵氧化物,研究兩者之間的異同,分析發(fā)現(xiàn)結(jié)構(gòu)的差異是導(dǎo)致這種現(xiàn)象的主要原因:立方相的Fe_3O_4較大的晶胞體積及更高的空隙率相較于四方相的Fe_2O_3更適于鋰離子的穿插而不會產(chǎn)生較大的體積變化,所以前者在50 mA g~(-1)下循環(huán)15周,可以獲得921.1 mAh g~(-1)的可逆比容量,而后者的可逆比容量僅有328.3 mAh g~(-1)。(3)除去成分、形貌、結(jié)構(gòu)因素,還利用鐵基和錳鐵二元金屬材料,研究了影響具有類似基礎(chǔ)性質(zhì)材料的性能的因素。采用水熱法,制備了同為逆尖晶石相的Fe_3O_4和MnFe_2O_4。研究發(fā)現(xiàn),兩者的電化學(xué)性能差異很大,分析其儲能機理,Fe_3O_4的儲能反應(yīng)是可逆的,而MnFe_2O_4會隨著循環(huán)的進(jìn)行分解成具有較小尺度的Fe_3O_4和MnO。儲能機理的差異,導(dǎo)致可逆的Fe_3O_4具有更加穩(wěn)定的循環(huán)性能,而隨著材料分解帶來的結(jié)構(gòu)崩塌使得在55次循環(huán)以后,MnFe_2O_4的可逆比容量只有Fe_3O_4的一半。2、對于鈉離子電池用金屬基負(fù)極材料,以錫基金屬材料為主。(1)以SnS_2為研究對象,探索了制備具有良好儲鈉潛力的片狀SnS_2材料的方法,并對影響其成長的原料配比、反應(yīng)時間進(jìn)行了規(guī)律性研究,探索了它的成核生長機理,分析了這些反應(yīng)條件對其成分、結(jié)構(gòu)、形貌的影響規(guī)律。(2)而后對具有合適結(jié)構(gòu)的SnS_2材料進(jìn)行不同碳材料的復(fù)合,研究不同碳材料、不同碳材料摻入量對復(fù)合材料的性能影響規(guī)律,探索其儲能及碳材料改性機理的作用方式,獲得具有優(yōu)異儲鈉性能的錫基復(fù)合負(fù)極材料。
[Abstract]:Metal base material, due to its high theoretical capacity, low working voltage and stable characteristics, simple preparation process and become a kind of potential anode materials. But its electrochemical performance in the circulation process because of the dramatic volume changes caused by instability, has been a major barrier to hinder its market. This paper is devoted to to build a stable electrochemical performance of two battery based anode materials for metal based characterization methods explores the two cell based anode materials for metal nucleation and growth mechanism of reaction conditions on the composition, structure, the effect rules of morphology, and the combination of all kinds of electrochemical techniques of the two cell mechanism can use base anode materials for metal storage, analysis of its composition, structure and morphology of the influence of changes on the electrochemical nature, so as to obtain metal based cathode materials prepared with excellent electrochemical performance The effective process of metal based cathode materials. The research can be divided into lithium ion batteries and sodium ion batteries with two parts of.1 for lithium ion battery based anode materials with metal, iron and manganese manganese base, mainly two yuan metal materials. (1) transition metal Mn as the base point, research the material composition, affect the morphology change on its performance. The manganese salt and ammonia as the main reactants, Mn_3O_4 spinel phase were prepared by hydrothermal method, the surface material appears with crystal nano rod, because the material has larger size dimensions, and the conductive rate is low, the charge and discharge in the process of wetting material and electrolyte, ion / electron diffusion transfer is not ideal, the volume change of the material is more serious, which leads to the electrochemical properties of the material are not ideal. In order to solve this problem, the introduction of graphene oxide reduction of support material Method, material and structure in the maintenance of stability and improve the conductivity at the same time, it analyzed the influence on the reduction of graphene oxide composite morphology changes, on the composite nucleation growth mechanism, improve the mechanism of energy storage and energy storage, obtained has good cycle stability and rate performance of Mn_3O_4/ reduction of graphite oxide graphene, the initial discharge capacity of up to 897.2 mAh g~ (-1), after 100 cycles, the capacity ratio remained at 450 mAh g~ (-1), is not to join the reduction of graphene oxide materials before capacity 4 times. In the study found that although the cycle stability of Mn_3O_4/rGO was improved for the first time in Kulun, but the material efficiency is still not ideal, this is a direct result of the reversible capacity of composite materials is low, therefore, the structure of material was redesigned, on the surface of composite package wrapped in a layer of polypyrrole, For the first time in order to reduce the circulation of solid electrolyte interface (SEI) film is formed when the capacity loss for the first time, Kulun efficiency are almost double the growth, at the same time, the analysis of EIS test method and master the mechanism of polypyrrole layer. (2) the use of iron-based metal material, study the effects of the properties of the theoretical capacity of.Fe_2O_3 to the change of Fe_3O_4 was significantly higher than that of material structure, but the actual test capacity is often low. With the hydrothermal synthesis of the above two kinds of iron oxides, the similarities and differences between the two studies, analysis found that the differences in the structure is the main reason of this phenomenon: cubic Fe_3O_4 large cell volume and higher rate of phase space compared to the tetragonal phase Fe_2O_3 is more suitable for the lithium ion with without generating large volume change, so the former in 50 mA g~ (-1) cycle for 15 weeks, you can get 921.1 mAh g~ (-1) reversible specific capacity, The latter than the reversible capacity was only 328.3 mAh g~ (-1). (3) to remove the composition, morphology, structure factors, using iron and ferromanganese two yuan metal materials, performance factors studied with similar basic properties of materials. By hydrothermal method, were prepared with Fe_3O_4 and inverse spinel the MnFe_2O_4. study found that the electrochemical performance difference, analysis of the mechanism of energy storage, Fe_3O_4 storage reaction is reversible, while MnFe_2O_4 will decompose into circulation with difference has smaller scale Fe_3O_4 and MnO. energy storage mechanism, which can be the inverse of the Fe_3O_4 has a more stable cycle performance, and with the material decomposition the collapse of the structure after 55 cycles, the reversible capacity of MnFe_2O_4 is only half the Fe_3O_4.2 for sodium ion batteries with metal tin based anode materials, metal materials. (1) with SnS_2 as the research object, To explore the method of SnS_2 sheet material preparation has good storage potential of sodium, and influence the growth of raw material ratio, reaction time were studied and explored its nucleation and growth mechanism, analyzed the reaction conditions on the composition, structure and morphology of the influence law. (2) and composite different carbon materials on the structure of SnS_2 with suitable materials, the effects of different carbon materials, carbon materials doped with different properties of composite materials, mode of action and explore its mechanism of modification and storage of carbon material, Sn based composite anode material has excellent storage performance of sodium.

【學(xué)位授予單位】：常州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TB34;TM912

【參考文獻(xiàn)】

相關(guān)期刊論文 前7條

1 陸浩;劉柏男;y団，

本文編號：1505207