US EPA

4270005 

Journal Article 

Fluorinated solvents for high-voltage electrolyte in lithium-ion battery 

Yan, G; Li, X; Wang, Z; Guo, H; Peng, W; Hu, Q; Wang, J 

2017 

Yes 

Journal of Solid State Electrochemistry
ISSN: 1432-8488
EISSN: 1433-0768 

21 

6 

1589-1597 

10.1007/s10008-017-3508-4 

WOS:000401736100008 

The major obstacle for the application of high-voltage cathode materials is the anodic instability of the electrolyte. On the guidance of density functional theory calculation, we develop a new high-voltage electrolyte comprising 1 mol L-1 LiPF6 dissolved in fluoroethylene carbonate (FEC) and ethyl difluoroacetate (DFEAc) (FEC/DFEAc = 3:7 in wt.% ratio). It shows a high conductivity (9.48 mS cm(-1)) and high anodic stability compared with the conventional electrolyte of 1 mol L-1 LiPF6 dissolved in ethylene carbonate (EC) and ethyl-methyl carbonate (EMC) (EC/EMC = 3:7 in wt.% ratio). In addition, Li/LiNi0.5Co0.2Mn0.3O2 half-cells with the new electrolyte display an excellent cycling ability with capacity retention of 89.23% after 100 cycles at 4.6 V (vs. Li/Li+). Although the electrolyte still will be oxidized at the cathode surface, the Li2CO3 and carbon-fluoride species originated from DFEAc and FEC are beneficial to building a stable cathode/electrolyte interface as revealed by the TEM and XPS results. 

Ethyl difluoroacetate; High-voltage electrolyte; Lithium-ion battery; Co-solvent; Lithiumnickel cobalt manganese oxide