本文選題：釩電池 + 穩(wěn)定性　； 參考：《東北大學(xué)》2014年博士論文

【摘要】：全釩氧化還原液流電池(Vanadium redox flow battery,簡稱釩電池)是基于VO2+/VO2+與V2+/V3+電對的新型儲能電池技術(shù),能量存儲于電解液中。釩電池與傳統(tǒng)的蓄電池相比,具有可快速、大容量充放電,自放電率低,電池結(jié)構(gòu)簡單的特點。如何獲得比能量高、性能穩(wěn)定的電解液就是釩電池的關(guān)鍵問題之一。隨著我國可再生能源法的正式實施,國家對風(fēng)能、太陽能等新型能源發(fā)電非常重視。發(fā)展可再生能源需要大容量儲能技術(shù)與之配套,結(jié)合我國具有豐富釩資源的優(yōu)勢,這就為建立大規(guī)模、低成本、可廣泛使用的釩電池儲能系統(tǒng)提供了廣闊的發(fā)展空間。釩電池正負(fù)極電解液的基本組成為不同價態(tài)的釩離子+H2SO4+水,與其它二次電池不同,釩電池電解液不僅是導(dǎo)電介質(zhì),更是實現(xiàn)能量存儲的電活性物質(zhì),是釩電池儲能及能量轉(zhuǎn)化的核心,因此釩電池的充放電效率、運行壽命和能量密度等關(guān)鍵性能都與電解液性能密切相關(guān),特別是與電解液的的熱力學(xué)性質(zhì)有關(guān)。本課題主要研究的內(nèi)容有：(1)在電解液中加入不同的添加劑,并進(jìn)行電位滴定和紫外定量分析,考察釩電池電解液的穩(wěn)定性,討論添加劑對釩電池電解液還原性的影響。結(jié)果表明：釩電池正極電解液的溫度越高,V(V)溶液越不穩(wěn)定；溫度相同的情況下,溶液中V(V)的濃度較高時,溶液穩(wěn)定性變差；在電解液中加入少量的低濃度的添加劑時,可以明顯的提高電解液的穩(wěn)定性；H2SO4濃度恒定為2mol/L的情況下,V(V)濃度為1.5mol/L時,所選用的五種添加劑中草酸鈉、草酸銨所起到的穩(wěn)定效果較佳,當(dāng)V(V)濃度為1.8mol/L,溫度為40℃時,較適合選擇尿素和CTAB,溫度為50℃時,適合選擇草酸鹽；在紫外定量分析中,在不同濃度,不同溫度下加入草酸鈉和草酸銨后釩電池電解液中V4+含量均較高,草酸鈉和草酸銨對于V5+的穩(wěn)定性起到了抑制沉淀析出的作用。(2)利用電化學(xué)工作站測定循環(huán)伏安曲線、交流阻抗譜等研究添加劑對電解液的電化學(xué)反應(yīng)可逆性及反應(yīng)活性等性能的影響。結(jié)果表明：釩電解液中加入不同濃度添加劑時,電極反應(yīng)活性有很大的提高,反應(yīng)的可逆性也有上升,尤其草酸鈉、草酸銨的陽極峰電流和陰極峰電流均較大；1.5mol/L VOSO4的硫酸溶液比1.8mol/L VOSO4的硫酸溶液有更好可逆性與電化學(xué)活性；加入添加劑后,電解液的電化學(xué)性能有所提升,交流阻抗譜中,加入草酸鈉、草酸銨時電化學(xué)反應(yīng)阻抗有所降低；加入3%CTAB.2%尿素時,電化學(xué)反應(yīng)阻抗增大。(3)采用電導(dǎo)法測定極稀水-‘VOSO4二元溶液體系的解離常數(shù),釩電池電解液中釩離子對的解離常數(shù)和釩離子的活度與電池性能直接相關(guān),而且解離常數(shù)與溫度有關(guān),而與濃度無關(guān),研究其隨溫度和組成的變化規(guī)律,進(jìn)而研究釩電池的相關(guān)熱力學(xué)性質(zhì),為進(jìn)一步優(yōu)化釩電池用電解液的工作提供部分理論基礎(chǔ)。結(jié)果表明：硫酸氧釩極稀水溶液的電導(dǎo)率κ值隨濃度的升高而增加,隨溫度的升高而降低；極限摩爾電導(dǎo)A。隨溫度的升高而增加；采用改進(jìn)的Ostwald稀釋定律和改進(jìn)的Davies方程估算了硫酸氧釩離子對解離度a、活度系數(shù)γ和溶液的真實離子強度I；應(yīng)用Fouss法和Shedlovsky法兩種不同方法進(jìn)行數(shù)據(jù)處理,解離常數(shù)、氧釩離子的遷移數(shù)、氧釩離子半徑數(shù)據(jù)可以作為參考,解離度a隨濃度和溫度的升高而減��；計算不同溫度下硫酸氧釩離子對解離過程的各熱力學(xué)函數(shù)△G0、 △H0、△S0、△CP0值,并求得解離常數(shù)Kd與溫度的關(guān)系經(jīng)驗方程式等等,可作為研究硫酸氧釩水溶液的熱力學(xué)參考數(shù)據(jù),為三元、四元溶液體系的研究提供理論依據(jù)。
[Abstract]:Vanadium redox flow battery (Vanadium redox flow battery) is a new energy storage battery technology based on VO2+/VO2+ and V2+/V3+ electric pairs. The energy is stored in the electrolyte. Compared with the traditional battery, vanadium battery has the characteristics of fast, large capacity charging and discharging, low self discharge rate and simple battery structure. How to obtain the specific energy High volume, stable performance electrolyte is one of the key problems of vanadium batteries. With the formal implementation of renewable energy law in China, the state attaches great importance to new energy generation, such as wind energy and solar energy. The development of renewable energy needs large capacity energy storage technology and matching, combined with the advantages of rich vanadium resources in China, this is to establish a big regulation The model, low cost and widely used vanadium battery energy storage system provides a broad development space. Vanadium battery positive and negative electrolyte is composed of vanadium ion +H2SO4+ water with different valence states. Unlike the other two batteries, the electrolyte of vanadium battery is not only conductive medium, but also an electroactive material for energy storage. It is the energy storage and energy of vanadium battery. The key properties of the quantity transformation are that the charge discharge efficiency, the operating life and the energy density of the vanadium battery are closely related to the performance of the electrolyte, especially the thermodynamic properties of the electrolyte. The main contents of this study are as follows: (1) adding different additives in the electrolyte and conducting potential titration and ultraviolet quantitative analysis. The stability of the electrolyte of vanadium battery was investigated and the effect of additives on the reducibility of the electrolyte was discussed. The results showed that the higher the temperature of the electrolyte of the vanadium battery was, the more unstable the V (V) solution was. Under the same temperature, the stability of the solution was worse when the concentration of V (V) was high, and a small amount of low concentration in the electrolyte was added to the electrolyte. When adding agent, the stability of the electrolyte can be obviously improved; when the concentration of H2SO4 is constant at 2mol/L, when the concentration of V (V) is 1.5mol/L, the stability effect of sodium oxalate and ammonium oxalate in the five additives is better. When V (V) concentration is 1.8mol/L and the temperature is 40, it is more suitable for the selection of urea and CTAB, when the temperature is 50 C. In the UV quantitative analysis, the content of V4+ in the electrolyte of vanadium battery after adding sodium oxalate and ammonium oxalate at different concentrations and temperatures is higher. Sodium oxalate and ammonium oxalate play a role in inhibiting precipitation in the stability of V5+. (2) use electrochemical station to determine the cyclic voltammetry curve, AC impedance spectroscopy and so on. The results show that the reaction activity of the electrode is greatly improved and the reversibility of the reaction increases, especially the Yang Jifeng current and the peak current of the cathode of ammonium oxalate; 1.5mol/L VOSO4. The sulfuric acid solution has a better reversible and electrochemical activity than the 1.8mol/L VOSO4 sulphuric acid solution; after adding the additive, the electrochemical performance of the electrolyte is improved. The electrochemical impedance of the electrochemical reaction is reduced when the sodium oxalate is added to the AC impedance spectrum, and the electrochemical impedance increases when the 3%CTAB.2% urea is added. (3) the conductivity method is used to measure the electrochemical impedance. The dissociation constant of VOSO4 two element solution system is constant. The dissociation constant of vanadium ion pair and the activity of vanadium ion in the electrolyte of vanadium battery are directly related to the performance of the battery, and the dissociation constant is related to the temperature, but it has nothing to do with the concentration, and studies the variation of the vanadium with the temperature and composition, and then studies the related thermodynamic properties of the vanadium battery. The theoretical basis for further optimization of the electrolyte for vanadium batteries is provided. The results show that the conductivity kappa value of the extremely dilute aqueous solution of vanadium sulfate increases with the increase of the concentration, and decreases with the increase of the temperature; the limit molar conductance A. increases with the increase of temperature; the improved Ostwald dilution law and the improved Davies equation are used. The dissociation degree a, the activity coefficient gamma and the true ionic strength I of the solution are calculated. The data processing, the dissociation constant, the migration number of vanadium ions, the oxygen vanadium ion radius data can be used as reference, the dissociation degree a decreases with the increase of concentration and temperature, and the difference temperature is calculated by two different methods of Fouss and Shedlovsky. The thermodynamic functions of the dissociation process, Delta G0, Delta H0, Delta S0, Delta CP0 value, and the relationship between the dissociation constant Kd and the temperature are obtained, and the thermodynamic reference data for the study of the solution of vanadium sulfate can be used as a theoretical basis for the study of three yuan and four element solution systems.
【學(xué)位授予單位】：東北大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TM912

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