Studies of the transport properties in lithium-intercalated NiPS 3

Abstract

We have investigated the electrochemical and transport properties of lithium-intercalated NiPS 3. Thermodynamic and kinetic results have been obtained by the modified galvanostatic intermittent titration technique for the long-time regime in the compositional range 0 ⩽ x ⩽ 1.5. The chemical diffusion coefficient of lithium in Li x NiPS 3 is composition dependent and the average value is 10 −9 cm 2 s −1 at room temperature. The partial ionic conductivity is estimated from the experimental determination of D ∗ and W and a value of σ i t e ( Li) is 2 × 10 −3 ω −1 cm −1 at x = 1.0. These transport properties are compared with those obtained in a galvanic cell with a composite electrode, i.e. a mixture of active material, solid electrolyte, acetylene black and polytetrafluoroethylene. Electrochemical titration during the discharge under moderate current drain shows lower values for the transport properties in a medium which is out of equilibrium.