硼掺杂镍酸锂的改性研究  

Enhanced electrochemical performance of LiNiO_(2) by B doping

作　　者：张宁 厉英 倪培远 ZHANG Ning;LI Ying;NI Pei-yuan(School of Metallurgy,Northeastern University,Shenyang 110819,China;Liaoning Key Laboratory for Metallurgical Sensor and Technology,Shenyang 110819,China)

机构地区：[1]东北大学冶金学院,沈阳1108192 [2]辽宁省冶金传感器及技术重点实验室,沈阳110819

出　　处：《工程科学学报》2021年第8期1012-1018,共7页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(51834004,51774076,51704062)。

摘　　要：采用共沉淀法制备了Ni(OH)_(2)前驱体材料,通过高温固相法制备了LiNiO_(2)和B掺杂LiNiO_(2)(B的摩尔分数为1%),利用X射线衍射(XRD)、里特维尔德(Rietveld)精修、扫描电子显微镜(SEM)、恒流充放电测试、循环伏安(CV)和电化学阻抗谱(EIS)对材料的晶体结构、表面形貌和电化学性能进行了系统性表征.XRD和Rietveld精修结果表明,LiNiO_(2)和B掺杂LiNiO_(2)均具有良好的层状结构,B因为占据在过渡金属层和锂层的四面体间隙位而导致掺杂后略微增大材料的晶格参数和晶胞体积,同时增大了LiO_(6)八面体的间距,进而促进锂离子运输.由于掺杂的B的摩尔分数仅为1%,LiNiO_(2)和B掺杂LiNiO_(2)均表现为直径10μm左右的多晶二次颗粒,且一次颗粒晶粒尺寸没有明显区别.长循环数据表明B掺杂可以有效提高材料的循环容量保持率,经100次循环后,B掺杂样品在40 mA·g^(−1)电流下的容量保持率为77.5%,优于未掺杂样品(相同条件下容量保持率为66.6%).微分容量曲线和EIS分析表明B掺杂可以有效抑制循环过程中的阻抗增长.The application markets for portable electronics,battery-operated electric vehicles,and large-scale energy-storage grids have been expanding rapidly for the past ten years,which has attracted massive attention to the investigation and development of batteries with high energy density,long cycle life,high safety,and low cost.A commonly used lithium-ion battery consists of intercalation-type materials,such as LiCoO_(2) as cathode and graphite as an anode.Owing to technical difficulties,including high cost,low stability,and the poor safety of Li,the large-scale application of the high-energy Li anode is still premature.A more common strategy than the one mentioned above for improving the energy density of Li-ion batteries is to develop a cathode material with high specific capacity and low cost,such as LiNi_(1-x-y)Co_(x)Mn_(y)O_(2)(NCM)and LiNi_(1-x-y)Co_(x)Al_(y)O_(2)(NCA).Among the NCMs and NCAs,Co is more expensive and less abundant than Ni,Mn,and Al.Presently,high-nickel,low-cobalt NCMs,and NCAs have attracted huge attention as suitable cathodes for both academic and industrial purposes.LNiO2 can be regarded as the Ni content increasing to 100%for NMCs and NCAs,which stood as the“holy grail”of layered cathodes.This study aims to investigate the structural and electrochemical stability of LiNiO_(2) and B-doped LiNiO_(2).In this study,Ni(OH)_(2) was synthesized by a coprecipitation method using a continuous stirred tank reactor(CSTR).LiNiO_(2) and B-doped LiNiO_(2) were synthesized by high-temperature solid-state sintering.The crystal structure,surface morphology,and electrochemical performance were investigated by X-ray diffraction(XRD),Rietveld refinement,scanning electron microscopy(SEM),constant current charge-discharge,cyclic voltammetry(CV),and electrochemical impedance spectroscopy(EIS).XRD and Rietveld refinement results indicate that B-doping could slightly increase the lattice parameters and unit cell volume due to the occupancy of B in the tetrahedral site.Meanwhile,the LiO_(6) slab distance increas

关 键 词：硼 掺杂 镍酸锂 正极材料 锂离子电池 

分 类 号：TM912.9[电气工程—电力电子与电力传动]