To seek the compatibility between LiNi0.5Mn1.5O4 and electrolyte based upon lithium bis(oxalate)borate (LiBOB) and sulfolane (SL), the electrochemical performances of 0.7molL−1 LiBOB–SL/DMC (1:1) electrolyte are investigated. This electrolyte has characteristic of good stability against oxidative decomposition (5.3V, vs. Li/Li+) and satisfactory safety performance. When used in LiNi0.5Mn1.5O4/Li cells, this electrolyte exhibits several advantages, such as stable cycle performance, low cell resistance, good rate performance, and high discharge voltage plateau. It suggests that LiBOB–SL/DMC electrolyte has good compatibility with LiNi0.5Mn1.5O4 cathode, and would be an attractive electrolyte for 5V high voltage lithium-ion batteries based upon LiNi0.5Mn1.5O4 cathode.