%0 Journal Article
%K Diffusion
%K Lithium compounds
%K Secondary cells
%K Electrolysis
%K Phosphorus compounds
%K Ultraviolet spectra
%K Visible spectra
%A Sarah G Stewart
%A John S Newman
%B Journal of The Electrochemical Society
%D 2008
%F Batt
%G eng
%N 1
%P F13-F16
%R 10.1149/1.2801378 
%T The Use of UV/vis Absorption to Measure Diffusion Coefficients in LiPF<sub>6</sub> Electrolytic Solutions
%V 155
%! J. Electrochem. Soc.
%X <p>This work describes the measurement of the diffusion coefficient in lithium-battery electrolytic solutions. We have adapted the method of restricted diffusion to measure diffusion coefficients of LiPF<sub>6</sub> in various solvents using ultraviolet/visible (UV/vis) absorption. The use of UV/vis absorption provides a simple alternative to more arduous experiments and reduces the potential for experimental error due to side reactions. The diffusion coefficient was seen to decrease with concentration according to the following:</p><p><em>D</em> = 3.018 x 10<sup>-5</sup> exp(-0.357c) for LiPF<sub>6</sub> in acetonitrile and <em>D</em> = 2.582 x 10<sup>-5</sup> exp(-2.856c) for LiPF<sub>6</sub> in ethylene carbonate/diethyl carbonate (with <em>D</em> in cm<sup>2</sup>s and <em>c</em> in mol/L). This technique may be useful for any liquid solution with a UV-active species of <em>D</em> greater than 10<sup>-6</sup> cm<sup>2</sup>s.</p>