层状锰酸锂材料制备及性能研究

Study on the Preparation and Properties of Layered Manganic Acid Lithium Materials

目前国内外锂离子电池正极材料规模化的有钴酸锂、镍酸锂、锰酸锂、磷酸铁锂,锰系材料资源丰富、价格低廉、对环境无污染,锰酸锂具有尖晶石和层状两种结构,而层状LiMnO2具有无毒、安全、理论容量高等优点,已成为目前研究的热点。以专用的MnO2与电池级Li2CO3为原料,采用高温固相法,对材料进行合成,得到了合成层状锰酸锂的最佳条件为:原料中锂锰摩尔比为1.03∶1,氩气保护气氛下,合成温度为800℃,合成反应的恒温时间为10 h。材料在0.1C的初始充电比容量为235.6 m Ah/g,放电比容量可达148.4 m Ah/g,0.1C下放电时,材料循环20次时,材料的放电比容量约为160 m Ah/g;当材料在0.2C放电时,放电比容量120 m Ah/g以上。但纯相的LiMnO2材料高倍率充放电性能较差,目前距离商业化还有一定的距离。

At present,cathode materials for lithium ion batteries at home and abroad which are scale of production are lithium cobalt oxide,lithium nickel oxide,lithium manganese oxide,lithium iron phosphate and so on. Manganese series materials have several advantages such as rich in resources,low price and low environmental pollution,and manganic acid lithium has two layered structures which are spinel and layered,layered Li MnO2 has several advantages such as non-toxic,safe,high theoretical capacity,and it has become a hot research spot. With special MnO2 and battery grade Li2CO3 as raw materials,using high temperature solid-state method for materials synthesis,the optimal conditions of synthesis of layered lithium manganate have been obtained in which raw materials in lithium manganese molar ratio was 1. 03 ∶ 1,synthesis temperature is 800 ℃ and reaction time is 10 h under Ar atmosphere. When the material is at 0. 1C,the initial charge capacity is 235. 6 m Ah / g and discharge capacity can be up to 148. 4 m Ah / g,and after 20 cycles,the discharge capacity of the material is about 160 m Ah / g. When the material is at 0. 2C,the discharge capacity is 120 m Ah / g. However,the high rate charge and discharge performance of LiMnO2 materials are poor,and there is still a certain distance for the commercialization.