Energy Storage Science and Technology ›› 2014, Vol. 3 ›› Issue (6): 624-628.doi: 10.3969/j.issn.2095-4239.2014.06.010

• Research & development • Previous Articles     Next Articles

The cycle life investigation for spinel LiNi0.5Mn1.5O4 full cells

XIE Jia, PENG Wen, YANG Xulai   

  1. Institute of Engineering and Technology,Hefei Guoxuan High-Tech Power Energy Co., Ltd.,Hefei 230011,Anhui,China
  • Received:2014-08-09 Online:2014-11-01 Published:2014-11-01

Abstract: Due to the high specific energy and good cycle ability, secondary lithium-ion batteries have been adapted as the main power source for portable electronics in the past two decades. Recently this technology has been extended into the fast growing electric vehicle market. However such application posts further needs of battery technology advancement, especially higher energy density to ectend the driving range of electric vehicles. The higher energy density in batteries can be achieved by improving specific capacity of active materials or by increasing the working potential of the cathode materials. Among various high-voltage cathode materials, the spinel LiNi0.5Mn1.5O4 has been investigated as a promising cathode material for Li-ion batteries with high energy density. In this paper, LiNi0.5Mn1.5O4 / graphite and LiNi0.5Mn1.5O4 / Li4Ti5O12 are manufactured as the 32131-type cells, which offer more practical and reliable cell data compared with laboratory size coin-cells. The cathode electrode composite is LiNi0.5Mn1.5O4 : SP : KS-6 : PVDF = 91.0 : 3.5 : 1.0 : 4.5, and the two anode electrodes are Li4Ti5O12 : SP : KS-6 : PVDF = 90.0 : 4.0 : 1.0 : 5.0 and graphite : SP : CMC = 93.2 : 2.5 : 4.3, respectively. The cells are 7.5Ah (152 W·h/kg) for LiNi0.5Mn1.5O4/graphite with N/P=1.1 and 5.5 A·h (81 W·h/kg) for LiNi0.5Mn1.5O4/Li4Ti5O12 with N/P=0.9. The capacity retention is 90.1% for LiNi0.5Mn1.5O4 /graphite after 250 cycles with 0.5 C charge/discharge rate at room temperature. For LiNi0.5Mn1.5O4 /Li4Ti5O12 cell, the capacity retention is 97.2% after 200 cycles with 1.0 C charge/1.5 C discharge rate at room temperature, the cycle performance is almost the same with LiNi0.5Mn1.5O4/Li half cell. Therefore, the difference of cycle performance seems to be depended on the anodes. The capacity fading of the LiNi0.5Mn1.5O4/graphite can be explained by the impact of Mn dissolution, and active Li+ loss in the full-cell system through continuous SEI formation (electrolyte reduction) prompted by Mn reduced on the surface of graphite. LiNi0.5Mn1.5O4/Li4Ti5O12 cell whose capacity is limited by Li4Ti5O12 anode showed almost no SEI and has better cycling performance.

Key words: LiNi0.5Mn1.5O4, high voltage, cycling performance, failure mechanism

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