采用去离子水清洗以及添加不同Na_2SO_4杂质含量的方法研究了化学杂质对尖晶石LiMn_2O_4材料电化学性能的影响. 电感耦合等离子体发射光谱(ICP-AES)和离子色谱测试表明, 水洗后材料主要杂质元素Na, S均得到有效去除; 电化学测试表明, 水洗后材料放电比容量得到提高, 与含Na_2SO_4杂质LiMn_2O_4材料相比, 水洗后材料在2C常温循环及倍率性能上都明显优于含杂质LiMn_2O_4材料. 通过扫描电子显微镜(SEM)及能量色散谱(EDS)研究了Na, S化学杂质在电池体系中的存在形式及对材料电化学性能的影响. 结果表明, Na_2SO_4溶解于电解液中以及由Na离子在负极还原所引起的副反应将导致电池倍率及循环性能恶化.
The effect of chemical impurities on the electrochemical performance of spinel LiMn_2O_4 cathode was investigated by washing the cathode in deionized water and adding different amount of Na_2SO_4 impurity. Inductively coupled plasma/atomic emission spectrometer (ICP/AES) and ion chromatography results showed that Na and S was successfully eliminated by washing. Compared with impure LiMn2O4, the discharge capacity, the cycle performance and the rate capability were improved after washing. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) studies on fresh and cycled cathodes were conducted to understand the existing form of Na, S impurities and their effect on electrochemical performance. It was found that Na_2SO_4 dissolved into the electrolyte and Na+ reduced on anode could deteriorate both the rate capability and cycle performance.
参考文献
| [1] | Choi W;Manthiram A .Influence of fluorine on the electrochemical performance of spinel LiMn_(2-y-z)Li_yZn_zO_(4-η)F_η cathodes[J].Journal of the Electrochemical Society,2007,154(07):A614. |
| [2] | Chen ZH;Amine K .Capacity fade of Li1+xMn2-xO4-based lithium-ion cells[J].Journal of the Electrochemical Society,2006(2):A316-A320. |
| [3] | Xia Y G;Zhang Q;Wang H Y;Nakamura H Noguchi H Yoshio M .Improved cycling performance of oxygen-stoichiometric spinel Li_(1+x)AlyMn_(2-x-y)O_(4+δ) at elevated temperature[J].Electrochimica Acta,2007,52:4708. |
| [4] | Han J M;Myung S T;Sun Y K .Improved electrochemical cycling behavior of ZnO-coated Li_(1.05)Al_(0.1)Mn_(1.85)O_(3.95)F_(0.05) spinel at 55 ℃[J].Journal of the Electrochemical Society,2006,153(07):A1290. |
| [5] | Eftekhari A .Bundled nanofibers of V-doped LiNn_2SO_4[J].Spinel Solid State Communications,2006,140:391. |
| [6] | Yu L;Qiu X;Xi J;Zhu W T Chen L Q .Enhanced high-potential and elevated-temperature cycling stability of LiNn_2SO_4 cathode by TiO2 modification for Li-ion battery[J].Electrochimica Acta,2006,51:6406. |
| [7] | Tu J;Zhao X B;Cao G S;Zhuang D G Zhu T J Tu J P .Enhanced cycling stability of LiNn_2SO_4 by surface modification with melting impregnation method[J].Electrochimica Acta,2006,51:6456. |
| [8] | 阚素荣,卢世刚,李文成,王昌胤,伍乐,黄松涛.尖晶石锰酸锂粒度和离子改性对其循环性能的影响[J].稀有金属,2008(03):387-391. |
| [9] | Komaba S;Itabashi T;Kaplan B;Groult H Kumagai N .Enhancement of Li-ion battery performance of graphite anode by sodium ion as an electrolyte additive[J].Electrochemistry Communications,2003,5:962. |
| [10] | Komaba S;Itabashi T;Kimura T;Groult H Kumagai N .Opposite influences of K~+ versus Na~+ ions as electrolyte additives on graphite electrode performance[J].Journal of Power Sources,2005,146:166. |
| [11] | 黄文煌,严玉顺,万春荣,姜长印.Na+对Li/改性石墨电池循环性能的影响研究[J].电化学,2000(02):212-217. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%