利用一步碳热还原法制备了Li3-xNaxV2（PO4）3/C（x=0、0.01、0.02、0.03、0.05、0.08、0.10、0.15）复合正极材料,并用X射线衍射、扫描电镜、红外光谱、循环伏安法、电化学阻抗谱和恒电流充放电技术研究了掺杂对材料结构、微观形貌、充放电性能和Li＋脱出嵌入过程的影响。研究表明掺杂少量Na＋不影响材料Li3V2（PO4）3的基本结构,但可在Li3V2（PO4）3中形成电子缺陷,提高晶体内部原子的无序化程度,降低极化和电荷转移电阻,从而改善材料的电化学性能。与Li3V2（PO4）3/C相比,Li2.98 Na0.02 V2（PO4）3/C在倍率为15C下的第50次放电容量提高12.1mAh/g,具有较好的倍率性能和循环性能。
Li3-xNaxV2（PO4）3/C（x=0,0.02,0.05,0.08,0.10,0.15） were synthesized by a simple one-step carbothermal reduction technology.The effects of doping on the crystalline structure,morphology,charge and discharge performances and Li＋ intercalation process were studied by X-ray diffraction（XRD）,scanning electron microscope（SEM）,Fourier transfer infrared spectroscopy（FT-IR）,cyclic voltammetry（CV）,electrochemical impedance spectroscopy（EIS） and charge-discharge experiments.The results showed that a small amount of Na＋ did not change the basic structure of Li3V2（PO4）3,but it could not only form electronic defects in Li3V2（PO4）3 to improve the degree of the disorder of crystal lattice atoms,but also reduce the polarization and charge transfer resistance,improve the lithium ion diffusion coefficient,so the electrochemical properties of the material were improved.Compared to Li3V2（PO4）3/C,the 50th discharge capacity of Li2.98Na0.02V2（PO4）3/C increased 12.1mAh/g at 15C,respectively,exhibiting good rate capability and cycling performance.
参考文献
| [1] | Padhi AK.;Goodenough JB.;Nanjundaswamy KS. .PHOSPHO-OLIVINES AS POSITIVE-ELECTRODE MATERIALS FOR RECHARGEABLE LITHIUM BATTERIES[J].Journal of the Electrochemical Society,1997(4):1188-1194. |
| [2] | 冯哲圣,王焱,杨邦朝,向勇,赖玲庆.锂离子电池正极材料磷酸铁锂的研究现状[J].功能材料,2011(04):581-584. |
| [3] | 蒋志君.锂离子电池正极材料磷酸铁锂：进展与挑战[J].功能材料,2010(03):365-368. |
| [4] | Zhou XC;Liu YM;Guo YL .One-step synthesis of Li3V2(PO4)(3)/C positive material with high performance for lithium-ion batteries[J].Solid State Communications,2008(5/6):261-264. |
| [5] | Li HH;Jin J;Wei JP;Zhou Z;Yan J .Fast synthesis of core-shell LiCoPO4/C nanocomposite via microwave heating and its electrochemical Li intercalation performances[J].Electrochemistry communications,2009(1):95-98. |
| [6] | Morgan D.;Ceder G.;Saidi MY.;Barker J.;Swoyer J.;Huang H.;Adamson G. .Experimental and computational study of the structure and electrochemical properties of LixM2(PO4)(3) compounds with the monoclinic and rhombohedral structure[J].Chemistry of Materials,2002(11):4684-4693. |
| [7] | Sato M.;Yoshida K.;Saito M.;Uematsu K.;Toda K.;Ohkawa H. .Enhancement of discharge capacity of Li3V2(PO4)(3) by stabilizing the orthorhombic phase at room temperature[J].Solid state ionics,2000(1/4):137-142. |
| [8] | 刘素琴,李世彩,黄可龙,陈朝晖.Ti4+离子掺杂对Li3V2（PO4）3晶体结构与性能的影响[J].物理化学学报,2007(04):537-542. |
| [9] | Burba CM;Frech R .Vibrational spectroscopic studies of monoclinic and rhombohedral Li3V2(PO4)(3)[J].Solid state ionics,2007(26):3445-3454. |
| [10] | 童汇 .锂离子电池正极材料磷酸铁锂的制备与性能研究[D].中南大学,2007. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%