Lithium difluoro(oxalato)borate/ethylene carbonate + propylene carbonate + ethyl(methyl) carbonate electrolyte for LiMn2O4 cathode

✍ Scribed by M.H. Fu; K.L. Huang; S.Q. Liu; J.S. Liu; Y.K. Li

• Book ID: 104025791
• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 790 KB
• Volume: 195
• Category: Article
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2009.08.042

✦ Synopsis

Lithium difluoro(oxalato)borate (LiODFB) was investigated as a lithium salt for non-aqueous electrolytes for LiMn 2 O 4 cathode in lithium-ion batteries. Linear sweep voltammetry (LSV) tests were used to examine the electrochemical stability and the compatibility between the electrolytes and LiMn 2 O 4 cathode. Through inductively coupled plasma (ICP) analysis, we compared the amount of Mn 2+ dissolved from the spinel cathode in 1 mol L -1 LiPF 6 /EC + PC + EMC (1:1:3 wt.%) and 1 mol L -1 LiODFB/EC + PC + EMC (1:1:3 wt.%). AC impedance measurements and scanning electron microscopy (SEM) analysis were used to analyze the formation of the surface film on the LiMn 2 O 4 cathode. These results demonstrate that ODFB anion can capture the dissolution manganese ions and form a denser and more compact surface film on the cathode surface to prevent the continued Mn 2+ dissolution, especially at high temperature. It is found that LiODFB, instead of LiPF 6 , can improve the capacity retention significantly after 100 cycles at 25 • C and 60 • C, respectively. LiODFB is a very promising lithium salt for LiMn 2 O 4 cathode in lithium-ion batteries.