Use of non-conventional electrolyte salt and additives in high-voltage graphite/LiNi0.4Mn1.6O4 batteries

• Performance data of high-voltage graphite/LiNi0.4Mn1.6O4 full cells are shown.
• Beneficial impact of LiFAP with respect to LiPF6 in EC-DMC for high-voltage batteries is evidenced.
• Effect of F1EC and SA additives to LF30 on cyclability and self-discharge of full cells is reported.

The performance of full cells featuring high-voltage LiNi0.4Mn1.6O4 cathode and graphite anode with carbonate-based electrolytes, ethylene carbonate (EC) -dimethyl carbonate (DMC) with conventional LiPF6 and non-conventional Li[(C2F5)3PF3] (LiFAP) lithium salts with and without SEI-forming additives 1-fluoro ethylene carbonate (F1EC) 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 LiPF6 electrolyte (LP30), also in presence of 1.6% F1EC-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.