CAJ | 학술논문

通过共沉淀法与同相法相结合制备了掺锌的高稳定性Li(Ni1/3Co1/3Mn1/3)1-xZnxO2(x=O,0.02,0.05)正极材料.循环伏安(CV)曲线表明Zn掺杂使氧化峰与还原峰的电势差减小到0.09 v,电化学阻抗谱(EIS)曲线表明Zn掺杂使电极的阻抗从266Ω减小到102Ω.Li+嵌入扩散系数从1.20×10-11 cm2·s-1增大到2.54×10-11 cm2.s-1.Li(Ni1/3Co1/3Mn1/3)098Zn002O2正极材料以0.3C充放电在较高的截止电压(4.6V)下比其他两种材料的电化学循环性能更稳定,其第二周的放电比容量为176.2 mAh.g-1,室温下循环100周后容量几乎没衰减;高温(55℃)下充放电循环100周,其放电比容量平均每周仅衰减0.20％,远小于其他两种正极材料(LiNi1/3Co1/3Mn1/3O2平均每周衰减0.54％; Li(Ni1/3Co1/3Mn1/3)095Zn0.05O2平均每周衰减0.38％).Li(Ni1/3Co1/3Mn1/3)098Zn002O2正极材料以3C充放电时其放电比容量可达142 mAh·g-1,高于其他两种正极材料.电化学稳定性的提高归因于Zn掺杂后减小了电极的极化和阻抗,增大了锂离子扩散系数.
통과공침정법여동상법상결합제비료참자적고은정성Li(Ni1/3Co1/3Mn1/3)1-xZnxO2(x=O,0.02,0.05)정겁재료.순배복안(CV)곡선표명Zn참잡사양화봉여환원봉적전세차감소도0.09 v,전화학조항보(EIS)곡선표명Zn참잡사전겁적조항종266Ω감소도102Ω.Li+감입확산계수종1.20×10-11 cm2·s-1증대도2.54×10-11 cm2.s-1.Li(Ni1/3Co1/3Mn1/3)098Zn002O2정겁재료이0.3C충방전재교고적절지전압(4.6V)하비기타량충재료적전화학순배성능경은정,기제이주적방전비용량위176.2 mAh.g-1,실온하순배100주후용량궤호몰쇠감;고온(55℃)하충방전순배100주,기방전비용량평균매주부쇠감0.20％,원소우기타량충정겁재료(LiNi1/3Co1/3Mn1/3O2평균매주쇠감0.54％; Li(Ni1/3Co1/3Mn1/3)095Zn0.05O2평균매주쇠감0.38％).Li(Ni1/3Co1/3Mn1/3)098Zn002O2정겁재료이3C충방전시기방전비용량가체142 mAh·g-1,고우기타량충정겁재료.전화학은정성적제고귀인우Zn참잡후감소료전겁적겁화화조항,증대료리리자확산계수.
Highly stable Li(Ni1/3Co1/3Mn1/3)1-xZnxO2 (x=0,0.02,0.05) cathode materials doped with Zn are synthesized by solid-state reactions with co-precipitated precursors.Cyclic voltammetry (CV) curves reveal that the potential difference between oxidation and reduction decreases to 0.09 V,and from electrochemical impedance spectra (EIS) curves,the impedance of LiNi1/3Co1/3Mn1/3O2 cathode materials is reduced from 266 to 102 Ω.The diffusion coefficients of Li+ ions in intercalation processes increase from 1.20x 10-11 to 2.54 × 10-11 cm2· s-1.Li(Ni1/3Co1/3Mn1/3)098 Zn002O2 is stable at 0.3C (constant charge/discharge) at a high cut-off potential of 4.6 V vs Li/Li+.It has a second discharge capacity of 176.2 mAh· g-1 at 0.3C and 142 mAh·g-1 at 3C,and keep almost no decay after 100 cycles at room temperature.Furthermore,its average capacity loss per cycle at 55 ℃ is 0.20％,which is lower compared with 0.54％ for LiNi1/3Co1/3Mn1/3O2 and 0.38％ for Li(Ni1/3Co1/3Mn1/3)095 Zn005O2 after 100 cycles.The improved electrochemical stability of Zn-doped LiNi1/3Co1/3Mn13O2 is attributed to the reduced electrode polarization and impedance values,and an increased Li+ ion diffusion coefficient.