Si4+掺杂提高LiNi0.5Mn0.5O2的电化学性能  

Improving the electrochemical performance of LiNi0.5Mn0.5O2 by Si^4+doping

作　　者：解安福 唐发满 朱振光 XIE An-fu;TANG Fa-man;ZHU Zheng-guang(Minmetal Salt Lake Co.,Ltd.,Xining,Qinghai 810003,China)

机构地区：[1]五矿盐湖有限公司,青海西宁810003

出　　处：《电池》2020年第4期364-368,共5页Battery Bimonthly

摘　　要：将共沉淀法和固相法相结合,将Si 4+掺杂到LiNi 0.5 Mn 0.5 O 2中,合成LiNi 0.5-x Si x Mn 0.5 O 2(0≤x≤0.08)正极材料。通过XRD及精修、等离子体发射光谱(ICP)、SEM和透射电子显微镜(TEM)等方法,对合成材料的结构、成分和形貌进行分析。Si 4+掺杂不仅可降低材料的锂镍混排程度,还能增强结构稳定性,且不会改变材料的形貌。以40 mA/g(0.2 C)的电流在2.5~4.5 V充放电,LiNi 0.47 Si 0.03 Mn 0.5 O 2(x=0.03)正极材料具有最好的电化学性能,不仅比容量(149.25 mAh/g)较未掺杂材料(125.44 mAh/g)提高20%,而且容量保持率在120次循环后也提高了7.7%。Si 4+掺杂能降低材料的锂镍混排程度,有利于Li+的迁移;能提高材料的结构稳定性,抑制电压的下降并减轻极化。LiNi 0.5-x Si x Mn 0.5 O 2(0≤x≤0.08)cathode materials were prepared by combing co-precipitation method combing with solid-state method,Si 4+was doped into LiNi 0.5 Mn 0.5 O 2.The structure,composition and morphology of the synthesized material were analyzed by XRD and rietveld refinement,inductively coupled plasma(ICP),SEM and transmission electron microscopy(TEM)methods.Si 4+doping could not only reduce the degree of Li/Ni cation mixing,but also enhance the structural stability,did not change the morphology of the material.When charged-discharged with the current of 40 mA/g(0.2 C)in 2.5-4.5 V,LiNi 0.47 Si 0.03 Mn 0.5 O 2(x=0.03)cathode material indicated the best electrochemical performance.The specific discharge capacity(149.25 mAh/g)was 20%higher than that of undoped material(125.44 mAh/g),its capacity retention ratio was also improved 7.7%after 120 cycles.Si 4+doping could reduce the degree of Li/Ni cation mixing,which was in favor of Li+diffusion;could improve the structural stability of the material,slow down the voltage drop and reduce the polarization.

关 键 词：锂离子电池 LiNi0.5 Mn0.5O2 正极材料 Si4+掺杂 锂镍混排 

分 类 号：TM912.9[电气工程—电力电子与电力传动]