(長沙理工大學(xué) 化學(xué)與生物工程學(xué)院 電力與交通材料保護(hù)湖南省重點實驗室，長沙 410004)
摘 要: 采用電化學(xué)-量熱法研究以LiNi0.5Co0.2Mn0.3O2為正極材料的鋰離子電池在不同環(huán)境溫度和充放電倍率下的熱電化學(xué)性能。結(jié)果表明：環(huán)境溫度和充放電倍率是影響電池比容量的重要因素，隨著充放電倍率和環(huán)境溫度的增加，電池比容量逐漸減小。在低倍率(0.2C)下，電池充放電初始階段的熱流緩慢增大，且出現(xiàn)多個放熱峰；而在較高倍率(0.5、1.0、2.0C)下，電池充放電初始階段的熱流快速增長，且充電和放電過程分別僅出現(xiàn)一個明顯的放熱峰。通過熱電化學(xué)研究，可獲得電池充放電過程的產(chǎn)熱量、化學(xué)反應(yīng)焓變(ΔrHm)以及化學(xué)反應(yīng)熵變(ΔrSm)等熱力學(xué)參數(shù)。
關(guān)鍵字: LiNi0.5Co0.2Mn0.3O2；電化學(xué)-量熱法；熱電化學(xué)；熱力學(xué)參數(shù)；鋰離子電池
（Changsha University of Science and Technology, School of Chemistry and Biological Engineering, Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, Changsha 410004, China）
Abstract:The electrochemical-calorimetric method was adopted to study the thermo-electrochemistry performance of lithium ion batteries in which LiNi0.5Co0.2Mn0.3O2 acted as cathode materials at different ambient temperatures and charge-discharge rates. The results show that the discharge specific capacity decreases with increasing the charge-discharge rates and ambient temperatures. At 0.2C, the heat flow of the batteries increase slowly and appear a plurality of exothermic peaks, but at higher charge-discharge rates (0.5, 1.0 and 2.0C), the heat flow increases rapidly and only an exothermic peak appears at the charge and discharge stage, respectively. Through investigating the thermo- electrochemistry, a series of thermodynamic parameters of lithium ion batteries during charge-discharge process, such as the amount of heat, enthalpy change of chemical reaction (ΔrHm), entropy change of chemical reaction (ΔrSm), are achieved.
Key words: LiNi0.5Co0.2Mn0.3O2; electrochemical-calorimetric method; thermo-electrochemistry; thermodynamic parameters; lithium ion battery
