【摘要】：隨著經(jīng)濟的快速發(fā)展,環(huán)境污染、能源短缺已成為每個人都不得不面對的問題。鋰離子電池因其具有比能量高、循環(huán)壽命長、無記憶效應(yīng)、安全環(huán)保等優(yōu)點,吸引了能源、交通、環(huán)境、航天等各方面的廣泛關(guān)注。電解質(zhì)是鋰離子電池一個不可或缺的組成部分,性能優(yōu)良的電解質(zhì)是鋰離子電池獲得高電壓、高能量密度等優(yōu)點的保證。四氟硼酸鋰(LiBF_4)作為鋰離子電池的電解質(zhì)具有熱穩(wěn)定性好、對水分相對不敏感、毒性小、安全性高、能有效防止A1集電極的腐蝕、制備成本低等優(yōu)點,是鋰離子電池電解液中的重要組成,有較好的市場前景。本文采用溶液法,以氫氟酸、硼酸和碳酸鋰為原料制備電池級電解質(zhì)LiBF_4。利用IR、XRD、AAS、ICP-AES及DTA等對四氟硼酸鋰產(chǎn)物進行了表征,通過電池測試系統(tǒng)及電化學(xué)工作站對產(chǎn)物四氟硼酸鋰的電化學(xué)性能進行測試。本文主要研究內(nèi)容有以下幾個方面:(1)以氫氟酸、硼酸和碳酸鋰為原料,溶液法制備電池級四氟硼酸鋰產(chǎn)品,考查了反應(yīng)溫度、原料的摩爾比、蒸發(fā)量、結(jié)晶溫度等因素對四氟硼酸鋰產(chǎn)品產(chǎn)率及純度的影響。通過單因素實驗及正交實驗得到最佳工藝條件為反應(yīng)溫度7.5℃、原料摩爾比n(氫氟酸):n(硼酸):n(碳酸鋰)為4.05:1.00:0.56、乙醇蒸發(fā)量占溶劑量的65%、結(jié)晶溫度15℃。在此條件下得到四氟硼酸鋰純度為99.22%(原子吸收法測得),產(chǎn)品產(chǎn)率90.08%。(2)利用紅外光譜對自制的產(chǎn)物進行結(jié)構(gòu)分析、X射線衍射法對產(chǎn)物進行定性分析,證明自制產(chǎn)品中得到目標(biāo)產(chǎn)物L(fēng)iBF_4。利用原子吸收法測定目標(biāo)產(chǎn)物L(fēng)iBF_4的鋰離子,利用ICP-AES測定產(chǎn)物中的鋰離子及其他金屬雜質(zhì)離子,利用重量法(沉淀重量法和滴定重量法)對樣品中的氟硼酸根進行測定,上述三種純度分析結(jié)果表明最佳條件下樣品純度很高,高達99.00%以上。利用熱分析對四氟硼酸鋰進行表征,其在DTA圖譜中290～300℃處有吸熱峰,說明目標(biāo)產(chǎn)物L(fēng)iBF_4有良好的熱穩(wěn)定性。(3)將自制LiBF_4配制成電解液并制成紐扣電池,利用電池測試系統(tǒng)及電化學(xué)工作站對其進行電化學(xué)性能測定,證明其具有高充放電電壓及良好的循環(huán)性能。實驗表明溶液法制備電池級LiBF_4工藝可行。該工藝反應(yīng)條件溫和,副產(chǎn)物為水和二氧化碳易除去,產(chǎn)品純度高,溶劑循環(huán)利用,解決了傳統(tǒng)方法中一直采用腐蝕性、強毒性的試劑等致命缺點。
[Abstract]:With the rapid development of economy and environmental pollution, energy shortage has become a problem that everyone has to face. Li-ion battery has attracted wide attention in energy, transportation, environment and aerospace due to its advantages such as high specific energy, long cycle life, no memory effect, safety and environmental protection. Electrolyte is an indispensable part of lithium-ion battery, and the excellent electrolyte is the guarantee of obtaining high voltage and high energy density of lithium-ion battery. Lithium tetrafluoroborate (LiBF_4) as an electrolyte for lithium-ion batteries has the advantages of good thermal stability, relatively insensitive to water, low toxicity, high safety, and can effectively prevent corrosion of A1 collector and lower preparation cost. It is an important component of lithium ion battery electrolyte and has a good market prospect. In this paper, battery-grade electrolyte LiBF_4. was prepared from hydrofluoric acid, boric acid and lithium carbonate by solution method. The products of lithium tetrafluoroborate were characterized by IR,XRD,AAS,ICP-AES and DTA. The electrochemical properties of lithium tetrafluoroborate were tested by battery test system and electrochemical workstation. The main contents of this paper are as follows: (1) the battery grade lithium tetrafluoroborate was prepared by solution method using hydrofluoric acid, boric acid and lithium carbonate as raw materials. The reaction temperature, molar ratio of raw materials and evaporation were investigated. Effect of crystallization temperature on the yield and purity of lithium tetrafluoroborate. By single factor experiment and orthogonal experiment, the optimum conditions are as follows: reaction temperature 7.5 鈩，

本文編號：2208816