am6b02620_si_001.pdf (1.77 MB)
Download fileIonic Liquid–Organic Carbonate Electrolyte Blends To Stabilize Silicon Electrodes for Extending Lithium Ion Battery Operability to 100 °C
journal contribution
posted on 2016-05-30, 00:00 authored by Khalid Ababtain, Ganguli Babu, Xinrong Lin, Marco-Tulio F. Rodrigues, Hemtej Gullapalli, Pulickel
M. Ajayan, Mark W. Grinstaff, Leela Mohana Reddy AravaFabrication
of lithium-ion batteries that operate from room temperature to elevated
temperatures entails development and subsequent identification of
electrolytes and electrodes. Room temperature ionic liquids (RTILs)
can address the thermal stability issues, but their poor ionic conductivity
at room temperature and compatibility with traditional graphite anodes
limit their practical application. To address these challenges, we
evaluated novel high energy density three-dimensional nano-silicon
electrodes paired with 1-methyl-1-propylpiperidinium bis(trifluoromethanesulfonyl)imide
(Pip) ionic liquid/propylene carbonate (PC)/LiTFSI electrolytes. We
observed that addition of PC had no detrimental effects on the thermal
stability and flammability of the reported electrolytes, while largely
improving the transport properties at lower temperatures. Detailed
investigation of the electrochemical properties of silicon half-cells
as a function of PC content, temperature, and current rates reveal
that capacity increases with PC content and temperature and decreases
with increased current rates. For example, addition of 20% PC led
to a drastic improvement in capacity as observed for the Si electrodes
at 25 °C, with stability over 100 charge/discharge cycles. At
100 °C, the capacity further increases by 3–4 times to
0.52 mA h cm–2 (2230 mA h g–1)
with minimal loss during cycling.