(北京有色金屬研究總院 動(dòng)力電池研究中心,北京100088)
摘 要: 以偏鈦酸鋰(Li2TiO3)和二氧化鈦(TiO2)為原料,采用固相法合成鈦酸鋰(Li4Ti5O12),通過XRD、SEM和電化學(xué)測試等方法對合成的鈦酸鋰材料的結(jié)構(gòu)、形貌和電化學(xué)性能進(jìn)行表征,同時(shí)研究一次顆粒長大規(guī)律和反應(yīng)機(jī)理。結(jié)果表明:Li2TiO3是傳統(tǒng)固相法合成Li4Ti5O12的中間產(chǎn)物,用Li2TiO3為原料在720、750 ℃保溫10 h可合成純的Li4Ti5O12,制備的一次顆粒粒徑分別為270、278 nm,較用Li2CO3和TiO2為原料合成純相的溫度更低,一次顆粒粒徑更小。反應(yīng)期間,一次顆粒粒徑隨著反應(yīng)分?jǐn)?shù)的增大呈快速增長勢頭;反應(yīng)結(jié)束后,一次顆粒粒徑增長緩慢。750 ℃合成的Li4Ti5O12在充放電倍率為0.1C、1C、5C、9C時(shí),比容量分別為170、164、149、126 mA?h/g,在0.1C時(shí)循環(huán)200次容量保持率大于97%,顯示制備的Li4Ti5O12具有良好的電化學(xué)性能。
關(guān)鍵字: 偏鈦酸鋰;鈦酸鋰;固相法;電化學(xué)性能
(Research and Development Centre for Vechicle Battery and Energy Storage,
General Research Institute for Nonferrous Metals, Beijing 100088, China)
Abstract:The Li4Ti5O12 material was prepared by solid-state method with Li2TiO3 and TiO2 as the source of titanium and lithium. The crystalline structure,morphology and electrochemical performances of the samples were investigated by X-ray diffraction, scanning electron microscope and charge discharge test, and the growing regularity of primary particles and the reaction mechanism were studied at the same time. The results show that Li2TiO3 is an intermediate product for traditional method, pure Li4Ti5O12 materials are prepared at 720 and 750 ℃ for 10 h using Li2TiO3 as raw material, and the sizes of prepared fine primary particles are 270 and 278 nm, respectively, which are smaller than those using Li2CO3 and TiO2 as raw materials, and the temperature of pure phase Li4Ti5O12 obtained is lower. With increasing conversion of reaction, the size of primary particles increases rapidly, then increases slowly after the reaction finishes. The initial specific discharge capacities of Li4Ti5012 synthesized at 750 ℃ and the charge-discharge rate of 0.1C, 1C, 5C and 9C are 171, 164, 149 and 126.7 mA?h/g, respectively. After 200 cycles at 0.1C, it remains more than 97% of the initial specific discharge capacity, exhibiting excellent electrochemical performance.
Key words: Li2TiO3; Li4Ti5O12; solid-state method; electrochemical performance


