摘要
以三价铁(Fe2O3)为铁源,采用半固相-碳热还原法制备LiFePO4/C正极材料,对LiFePO4的铁位进行高价金属离子(Nb5+)掺杂制得LiFe1-xNbxPO4/C(x=0、0.01、0.03、0.05、0.07)复合正极材料。X射线衍射分析材料的晶型结构发现掺杂一定量的金属离子不会改变材料的晶型结构。对材料进行充放电循环性能测试表明,掺入高价金属离子会改善材料的电化学性能,其放电比容量有显著提高,循环稳定性也得到一定改善,同没有掺杂金属离子的LiFePO4/C相比尤其在大电流方面的优势更加明显。其中掺铌0.03的材料性能最好,在0.1 C放电倍率下,首次放电比容量可以达到160.57 mAh/g,1 C时首次放电比容量仍有136.43 mAh/g,而在大倍率10 C放电时,还保持在95 mAh/g。
LiFePO4/C cathode material was prepared by semi-solid phase-carbon-thermal reduction method,using ferric（Fe2O3） as Fe source,LiFe1-xNbxPO4/C（x=0,0.01,0.03,0.05,0.07） composite cathode materials were obtained with high-priced metal ions（Nb5＋） doped in Fe site.X-ray diffraction analysis of the crystalline structure of samples indicates that,doping a certain amount of metal ions does not change the crystalline structure of materials.The charge-discharge cycle performance tests show that,doping high-priced ions can improve the electrochemical properties of materials.The specific discharge capacity of the samples is improved greatly and cycling stability is also improved to some extent.Especially in large current field,the advantages are more obvious compared with no metal ions doped LiPePO4/C.LiFePO4/C sample doped with 3% Nb5＋ has the best performance,and the first discharge specific capacity is 160.57 mAh/g at 0.1 C,which is still 136.43 mAh/g at 1 C,while at 10 C,the discharge specific capacity still maintains 95 mAh/g.
出处
《电源技术》
CAS
CSCD
北大核心
2011年第3期267-270,共4页
Chinese Journal of Power Sources
基金
国家科技支撑计划(2007BAQ01055)
国家自然科学基金(50574063)
关键词
磷酸铁锂
碳热还原
Nb5+
高倍率
lithium iron phosphate
carbon-thermal reduction
Nb5＋
high rate
