(中南大學(xué) 冶金科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 以共沉淀法制備的球形Ni0.5Co0.3Mn0.2CO3粉末為前驅(qū)體，按一定的比例將碳酸鋰與前驅(qū)體混合，然后采用高溫固相法合成高振實(shí)密度球形LiNi0.5Co0.3Mn0.2O2正極材料。該材料的振實(shí)密度達(dá)到2.60 g/cm3，與商品化LiCoO2的密度相當(dāng)。SEM分析表明， LiNi0.5Co0.3Mn0.2O2正極材料與前驅(qū)體形貌有良好的繼承性，均為理想的球形。XRD物相分析表明，在不同合成溫度下的Li Ni0.5Co0.3Mn0.2O2產(chǎn)物均為具有α-NaFeO2層狀結(jié)構(gòu)的純相物質(zhì)，在較高合成溫度下所得材料的結(jié)晶度較高。電化學(xué)性能研究表明，在2.7~4.3 V的電壓范圍內(nèi)，電池的放電比容量在0.2C倍率下為168.1 mA∙h/g，在1C倍率下為157.6 mA∙h/g；經(jīng)50次循環(huán)后，兩種放電條件下的電池容量保持率分別為95.1%和97.2%，顯示出良好的電化學(xué)性能。
關(guān)鍵字: 鋰離子電池；正極材料；振實(shí)密度；Li Ni0.5Co0.3Mn0.2O2
（School of Metallurgical Science and Engineering Central South University, Changsha 410083, China）
Abstract:The high tap-density spherical LiNi0.5Co0.3Mn0.2O2 cathode materials were synthesized from coprecipitated Ni0.5Co0.3Mn0.2CO3 by high-temperature solid-state method. The tap-density of the material is as high as 2.60 g/cm3, which is similar to commercial LiCoO2. The SEM results reveal that the LiNi0.5Co0.3Mn0.2O2 cathode material has well kept the spherical morphology of the spherical precursor. The XRD results show that all the LiNi0.5Co0.3Mn0.2O2 samples have high purity phase, and the powders are much better crystallized at higher synthesis temperature. At 2.7−4.3 V, the discharge capacities reach 168.1 and 157.6 mA∙h/g at the rates of 0.2C and 1C, respectively. The capacity retentions after 50 cycles at 0.2C and 1C are 95.1% and 97.2%, respectively. This proves that the materials present excellent electrochemical performances.
Key words: Li-ion battery; cathode material; tap-density; Li Ni0.5Co0.3Mn0.2O2
