Impact of the flame retardant additive triphenyl phosphate (TPP) on the performance of graphite/LiFePO4 cells in high power applications

• This study presents an extensive characterization of a standard Li-ion battery (LiB) electrolyte containing different concentrations of the flame retardant triphenyl phosphate (TPP) in the context of high power applications. Electrolyte characterization shows only a minor decrease in the electrolyte flammability for low TPP concentrations. The addition of TPP to the electrolyte leads to increased viscosity and decreased conductivity. The solvation of the lithium ion charge carriers seem to be directly affected by the TPP addition as evidenced by Raman spectroscopy and increased mass-transport resistivity. Graphite/LiFePO4 full cell tests show the energy efficiency to decrease with the addition of TPP. Specifically, diffusion resistivity is observed to be the main source of increased losses. Furthermore, TPP influences the interface chemistry on both the positive and the negative electrode. Higher concentrations of TPP lead to thicker interface layers on LiFePO4. Even though TPP is not electrochemically reduced on graphite, it does participate in SEI formation. TPP cannot be considered a suitable flame retardant for high power applications as there is only a minor impact of TPP on the flammability of the electrolyte for low concentrations of TPP, and a significant increase in polarization is observed for higher concentrations of TPP. (C) 2014 Elsevier B.V. All rights reserved.

Subject headings

NATURVETENSKAP  -- Kemi -- Oorganisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Inorganic Chemistry (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

Keyword

BASIS-SETS

Flame retardant additive

ELECTROCHEMICAL PERFORMANCE

MIXED-SOLVENT

Electrolyte characterization

SOLVENT-CONTAINING ELECTROLYTES

FLUORINATED ALKYL PHOSPHATES

Triphenyl phosphate (TPP)

LEAN AD

JOURNAL OF CHEMICAL PHYSICS

Hybrid Pulse Power Characterization (HPPC)

V72

CARBONATE

1980

P5639

NONFLAMMABLE ELECTROLYTES

NEGATIVE ELECTRODE

Electrode/electrolyte interface

Graphite/LiFePO4 cell

RAY

LITHIUM-ION BATTERIES

ETHYLENE

PHOTOELECTRON-SPECTROSCOPY

Kemi med inriktning mot oorganisk kemi

Publication and Content Type

art (subject category)

ref (subject category)