劉素琴 文越華
摘 要:針對(duì)高穩(wěn)定性、高活性全釩液流電池電解液以及高能量密度單液流電池沉積型電對(duì)及固體電極電化學(xué)性能與電解質(zhì)溶液之間構(gòu)效關(guān)系、高穩(wěn)定性濃電解質(zhì)溶液化學(xué)理論及作用機(jī)制等關(guān)鍵科學(xué)問(wèn)題,以具備較大應(yīng)用潛力的全釩雙液流以及鋅/鎳、全鉛單液流電池體系電解質(zhì)的溶液化學(xué)為研究重點(diǎn),通過(guò)電化學(xué)測(cè)試與材料物性表征相結(jié)合,深入研究了電解質(zhì)溶液對(duì)全釩雙液流以及堿性沉積型鋅負(fù)極和電池性能的影響,闡明了電解液流速、鋅沉積面容量和電流密度的關(guān)聯(lián);考察了不同種類(lèi)的無(wú)機(jī)、有機(jī)添加劑以及添加劑中的官能團(tuán)對(duì)電解液的熱穩(wěn)定性以及電化學(xué)活性的影響,深入研究了電解液溶液及添加劑對(duì)固體氧化鎳正極活性和穩(wěn)定性的影響,探討了電解液添加劑與鋅負(fù)極和氧化鎳正極的相容性;研究了全鉛單液流電池電解質(zhì)溶液的物化性質(zhì),探明電解液組成對(duì)電極性能的影響規(guī)律;研究了電解液添加劑對(duì)全鉛單液流電池電極性能的影響及其作用機(jī)制;考察了支持電解質(zhì)對(duì)電解液的熱力學(xué)穩(wěn)定性、電化學(xué)活性以及循環(huán)穩(wěn)定性等的影響,優(yōu)化了電解液的組成,提高了電池充放電的能量效率和循環(huán)穩(wěn)定性。重要的創(chuàng)新點(diǎn)包括以下方面:(1)確定了對(duì)于全釩液流電池電解液的熱穩(wěn)定性和電化學(xué)性能具有積極作用的添加劑結(jié)構(gòu)和支持電解質(zhì)組成;(2)闡明全鉛單液流電池電解液中鉛活性離子對(duì)電極性能的影響規(guī)律,優(yōu)化了鉛離子濃度;(3)提出電解液中添加電解PbO2,降低沉積型PbO2電極極化,抑制鉛累積和枝晶的新方法,獲得了高活性、高沉積均勻性Pb負(fù)極和PbO2正極。
關(guān)鍵詞:全釩液流電池 沉積型單液流電池 電解液 添加劑 電極
Abstract:The all vanadium redox flow battery, Zn/Ni, PbO2/Zn、PbO2/Cu(Cd) and all lead single flow battery systems with great application potential and electrolyte of high concentration are taken as the focus of research. Influence of some inorganic additives and organic additives with various functional groups on the thermal stability and electrochemical performance of electrolyte of vanadium redox flow battery were investigated. The improved electrochemical performance may be ascribed to more active sites provided by -NH2 group and the enhanced hydrophilicity of theelectrode provided by -NH2 and -SO3H groups. Effects of methanesulfonic acid as supporting electrolyte on thermal stability and electrochemical performance are investigated. The electrochemical results show that V(IV)/V(V) exhibits superior electrochemical activity and reversibility in the mixture of 3 M H2SO4 and 7 M methanesulfonic acid, and the diffusion coefficient of V(IV) species, exchange current density and reaction rate constant become larger in the mixture of 3 M H2SO4 and 7 M methanesulfonic acid. In a flowing electrolyte, the electrochemical reaction characteristics and kinetics of electrode process of the metallic zinc, copper, cadmium and lead deposition and dissolution were investigated. The suitable deposition substrates are determined. The electrolyte conditions under which the metal ions can be evenly and rapidly deposited with high area capacity and high efficiency are gained. The effect laws of electrolyte additive on metal deposition morphology and electrochemical activity and its mechanism of action were investigated. The relationship between electrolyte flowing speed, deposition area capacity and current density was investigated. The energy efficiency and stability of batteries in the process of electrode enlargement and under high deposition area capacity has been improved. The innovations include:(1)The structure and component of additives that can improve the thermal stability and electrochemical performance of vanadium redox flow battery were determined.(2)the effect laws of lead ions in the electrolyte of all lead single flow batteries on the performance of electrodes were clarified.(3)The electrolytic PbO2 was added into the electrolyte, which lowered the over-potential of deposition type PbO2 electrodes and eliminated the accumulation of lead and the dendrite growth on the lead negative electrode.
Key Words:All vanadium redox flow battery;Deposition type single flow battery;Electrolyte;Additives;Electrode
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