Multicomponent 5V Cathodes for Li-ion Batteries
- PDF / 138,295 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 17 Downloads / 240 Views
1127-T03-08
Multicomponent 5V Cathodes for Li-ion Batteries Malgorzata K. Gulbinska,1 Boris Ravdel,1 Svetlana Trebukhova,1 Brian N. Hult2 and Sanjeev Mukerjee2 1
Yardney Technical Products, Inc., 82 Mechanic Street, Pawcatuck, CT 06379, U.S.A. 2 Department of Chemistry and Chemical Biology, 317 Egan Research Center, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, U.S.A. ABSTRACT In this study, the multicomponent electrode approach was used in an attempt to simultaneously improve the cell’s specific energy values by shifting the cathode’s voltage up to the 5V-region, combined with the increased specific capacity via addition of the second electrode component. The electrode materials were prepared by variety of synthetic methods (e.g. solid state, sol-gel, mechanical mixing etc.) and tested for lithium-ion intercalation properties. Structural properties and morphology of synthesized materials were characterized by X-ray diffraction (XRD) methods. The prospective 5V cathode materials were investigated as cathodes in the cells with lithium-metal counter electrode. INTRODUCTION Lithium-ion batteries (LIB) have progressed technically and commercially since their first implementation more than a decade ago. Nowadays, rechargeable lithium-ion cells ranging from 2 to 200 mAh with specific energies of >200 Wh/kg are built and used in a multitude of applications. However, non-incremental improvements, such as specific energies as high as 350 Wh/kg are required in order to meet the growing needs of the modern market. In order to achieve major advances in specific energy of LIB, novel concepts for lithium-ion battery chemistry and/or design, such as the multiphase electrodes, are highly desired. In former studies of the multicomponent cathodes such as LiMO2·Li2M’O3 (M=Co, Ni, Mn; M’=Ti, Zr, Mn), the addition of Li2M’O3 was found to enhance the stability of the positive-electrode material. The addition of the layered LiNi0.8Co0.2O2 material to lithium-manganese spinel Li1+xMn2-xO4 was found to inhibit the spinel dissolution in the electrolyte and reduce capacity losses during storage at elevated temperatures. Feasibility of preparation and possible advantages of manganese oxides-based composite cathodes were also discussed by Thackeray et al.1 Despite the challenges related to synthetic methods the authors agreed that the composite electrode systems are worth exploring.1,2 EXPERIMENT Sol-gel LiMn1.5Ni0.5O4 Spinel Syntheses LiNi0.5Mn1.5O4 powders were prepared by a sol-gel method using glycolic acid as a chelating agent. Li(CH3COO)·H2O, Ni(CH3COO)2·4H2O, and Mn(CH3COO)2·4H2O with cationic ratio of Li:Ni:Mn equal to 1:0.5:1.5 were dissolved in distilled water, and then added drop-wise to a
continuously stirred aqueous solution of glycolic acid. The pH of the solution was adjusted to 8.5-9.0 using ammonium hydroxide. The solution was then evaporated at 70-80°C until a transparent sol and then gel was obtained. The resulting gel precursor was decomposed at 500°C for ten hours in air, and calcined at 850°C in air
Data Loading...
