富锂锰过渡金属层状正极材料以其成本低、安全、容量高受到广泛关注,X射线衍射（XRD）和电化学性能测试显示以共沉淀结合煅烧成功合成富锂层状正极材料zLi2MnO3.（1-z）LiMn0.4Ni0.4Co0.2O2（z=0.2,0.4,0.6）。其中z=0.4组分的放电容量达到210mAh/g（2-4.8V,0.05C）,远高于z=0.6组分,而经20个充放电循环的稳定性也优于z=0.2组分。微分容量分析表明z=0.2组分中因Ni/（Co＋Mn）比值较大和Li2MnO3含量较少可能导致其容量逐渐衰减。z=0.6则因所含LiMn0.4Ni0.4Co0.2O2量较少,造成其放电容量较低;z=0.4拥有最佳Li2MnO3及LiMn0.4Ni0.4Co0.2O2组合使其容量和循环性能最好。
Lithium-rich-layered cathode materials zLi2MnO3·（1-z）LiMn0.4Ni0.4Co0.2O2（z=0.2,0.4,0.6） have been successfully synthesized by coprecipitation and calcination through the examinations with x-ray diffractometry（XRD） and electrochemical performance.The material of z=0.4 delivers discharge capacity 210mAh/g（2-4.8V,0.05C） better than that of z=0.6,and its cyclability after 20 cycles without fade is superior to that of z=0.2.The analysis of differential-capacity plot and electrochemical performance concerning 0.2Li2MnO3·0.8LiNi0.4Mn0.4Co0.2O2 indicates that the higher Ni/（Co＋Mn） ratio as well as the inherently smaller amount of Li2MnO2 could be the reason for capacity fade.However,the lower LiNi0.4Mn0.4Co0.2O2 content in z=0.6 could result in its lower capacity.The composition of z=0.4 with the optimal amount of Li2MnO3 to stabilize the material structure and that of active LiNi0.4Mn0.4Co0.2O2 to contribute the capacity has the best combination of capacity and cyclability.
参考文献
| [1] | Thackeray M M;Kang S H;Johnson C S .Li2MnO3 stabilized LiMO2(M = Mn, Ni, Co) electrodes for lithium-ion batteries[J].Electrochemistry Communications,2006,8(09):1531-1538. |
| [2] | Yang S;Song Y;Ngala K;Zavalij P Y,Whittingham M S .Performance of LiFePO, as lithium battery cathodc and comparison with manganese and vanadium oxides[J].Journal of Power Sources,2003,119(121):239-246. |
| [3] | J. Gao;A. Manthiram .Eliminating the irreversible capacity loss of high capacity layered Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]O_2 cathode by blending with other lithium insertion hosts[J].Journal of Power Sources,2009(2):644-647. |
| [4] | Arinkumar TA;Wu Y;Manthiram A .Factors influencing the irreversible oxygen loss and reversible capacity in layered Li[Li1/3Mn2/3]O2-Li[M]O-2 (M=Mn0.(5-y)Ni(0.5-y)Co2(y) and Ni1-yCoy) solid solutions[J].Chemistry of Materials: A Publication of the American Chemistry Society,2007(12):3067-3073. |
| [5] | Christopher S. Johnson;Naichao Li;Christina Lefief .Synthesis, Characterization and Electrochemistry of Lithium Battery Electrodes: xLi2MnO3·(1- x)LiMn_(0.333)Ni_(0.333)Co_(0.333)O2 (0 ≤x ≤ 0.7)[J].Chemistry of Materials: A Publication of the American Chemistry Society,2008(19):6095-6106. |
| [6] | Zhonghua Lu;L. Y. Beaulieu;R. A. Donaberger .Synthesis, Structure, and Electrochemical Behavior of Li[Ni_xLi_(1/3-2x/3)Mn_(2/3-x/3)]O_2[J].Journal of the Electrochemical Society,2002(6):A778-A791. |
| [7] | 李劼,郑建明,郭晓健,龚正良,杨勇.锂离子电池正极材料LiNi0.4 Co0.2 Mn0.4 O2的合成、表征及电化学性能[J].高等学校化学学报,2006(07):1311-1314. |
| [8] | Zhonghua Lu;J. R. Dan .Structure and Electrochemistry of Layered Li[Cr_xLi_((1/3-x/3))Mn_((2/3-2x/3))]O_2[J].Journal of the Electrochemical Society,2002(11):A1454-A1459. |
| [9] | Jung-Min Kim;Hoon-Taek Chung .Role of transition metals in layered Li[Ni,Co,Mn]O{sub}2 under electrochemical operation[J].Electrochimica Acta,2004(21):3573-3580. |
| [10] | Park SH;Kang SH;Johnson CS;Amine K;Thackeray MM .Lithium-manganese-nickel-oxide electrodes with integrated layered-spinel structures for lithium batteries[J].Electrochemistry communications,2007(2):262-268. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%