| CPC H01M 10/0568 (2013.01) [H01M 10/0525 (2013.01); H01M 10/0569 (2013.01); H01M 2300/0034 (2013.01)] | 9 Claims |

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1. A liquid electrolyte lithium secondary battery cell comprising:
a positive electrode material comprising a lithium transition metal-based oxide powder having a general formula
Li1+a((Niz (Ni0.5Mn0.5)y COx)1−k Ak)1−a O2, wherein A is a dopant, −0.025≤a≤0.025, 0.18≤x≤0.22, 0.42≤z≤0.52, 1.075<z/y<1.625, x+y+z=1 and k<0.01; and
an electrolyte composition comprising:
a) at least one cyclic carbonate, wherein the at least one cyclic carbonate is propylene carbonate,
b) monofluoroethylene carbonate,
c) at least one fluorinated acyclic carboxylic acid ester, wherein the at least one fluorinated acyclic carboxylic acid ester is 2,2-difluoroethyl acetate,
d) at least one electrolyte salt, wherein the at least one electrolyte salt is lithium hexafluorophosphate (LiPFO),
e) at least one lithium compound, wherein the at least one lithium compound is lithium bis(oxalato)borate,
f) at least one cyclic sulfur compound, wherein the at least one cyclic sulfur compound is 1,3,2-dioxathiolane 2,2-dioxide, and
g) at least one cyclic carboxylic acid anhydride, wherein the at least one cyclic carboxylic acid anhydride is maleic anhydride.
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