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LiNi0.5Mn1.5O4 (LNMO), which has an operating voltage of 4.8 vs Li/Li+ and a theoretical capacity of 147 mAh g−1, is an interesting cathode material for advanced lithium ion batteries. However, electrolyte decomposition at the electrode can gradually decrease the capacity of the battery. In this study, the surface of the LNMO cathode has been modified with phosphoric acid (PA) to improve the capacity of the LNMO/graphite full cell. Modification of LNMO cathodes by PA is confirmed by surface analysis. Additionally, the presence of lithium bis-(oxalato) borate (LiBOB) as an electrolyte additive further enhances the performance of PA modified LNMO/graphite cells. The improved performance of PA modified cathodes and electrolytes containing LiBOB can be attributed to the suppressed Mn and Ni deposition on the anode. Elemental analysis suggests that the Mn and Ni dissolution is significantly reduced compared to unmodified LNMO/graphite cells with standard electrolyte. [ABSTRACT FROM AUTHOR]

In this paper we report on the use of the ionic liquid N-butyl-N-methylpyrrolidinium bis(trifluoromethansulfonyl)imide, PYR14TFSI, in combination with a graphite and silicon electrodes at room temperature. The performance of the investigated electrodes has been considered in terms of specific capacity, cycling efficiency and cycling stability. The influence of two different binders on the performance of graphite electrode has also been considered. The results show that in electrolytic solutions based on PYR14TFSI the addition of an electrolyte additive is necessary for the formation of the solid electrolyte interphase (SEI). The reported results show also that the selection of the binder is important for the increase of the performance in graphite electrodes. Finally, the comparison of the performance of the investigated electrodes showed that silicon electrodes display higher compatibility with PYR14TFSI with respect to graphite electrodes. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]