Facile reduction of pseudo-carbonates: Promoting solid electrolyte interphases with dicyanoketene alkylene acetals in lithium-ion batteries

• Dicyanoketene ethylene and propylene acetals, DCKEA and DCKPA respectively, have been investigated as electrolyte additives for Li-ion batteries. The purpose was to assess the changes in reduction behaviour and solid electrolyte interphase (SEI) passivation properties upon replacing the carbonyl group of ethylene carbonate (EC) and propylene carbonate (PC) solvents, respectively, by the slightly more electronegative and highly conjugated =C(CN)(2) group. The experimental reduction potentials and the IR spectroscopy characterisation efforts were further supported by density functional theory (DFT) computations. The two additives were found to, in relatively small amount (0.5 wt%), provide beneficial effects on the capacity retention of 8 mAh cells cycled at 20 and 45 degrees C. Moreover, the additives proved to enhance the thermal stability of the lithiated graphite/electrolyte interface, as deduced from DSC measurements.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

cells

graphite anode

Thermal runaway

fluoroethylene

DFT

Additives

low-temperature performance

Dicyanoketene alkylene acetal

carbonate

additives

thermal-stability

vinyl ethylene carbonate

li-ion

density functionals

SEI

elevated-temperature

Li-ion battery

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art (ämneskategori)

ref (ämneskategori)