Use of non-conventional electrolyte salt and additives in high-voltage graphite/LiNi sub(0.4)Mn sub(1.6)O sub(4) batteries

The performance of full cells featuring high-voltage LiNi sub(0.4)Mn sub(1.6)O sub(4) cathode and graphite anode with carbonate-based electrolytes, ethylene carbonate (EC) -dimethyl carbonate (DMC) with conventional LiPF sub(6) and non-conventional Li[(C sub(2)F sub(5)) sub(3)PF sub(3)] (LiFAP) lithium salts with and without SEI-forming additives 1-fluoro ethylene carbonate (F sub(1)EC) and succinic anhydride (SA) is investigated. The results evidence the beneficial impact of EC-DMC-1M LiFAP electrolyte (LF30), with respect to EC-DMC-1M LiPF sub(6) electrolyte (LP30), also in presence of 1.6% F sub(1)EC-2% SA additives, on charge retention over cycling and on self-discharge of full cells. After the 25 cycles of the charge capability test, the charge retention reached values up to 70% with LF30 and 87% with LF30 and additives, and fully charged cells with LF30-additives delivered 53% of the stored charge after one week in OCV.