Grand canonical Monte Carlo investigations of electrical double layer in molten salts.

Results of the Monte Carlo simulation of the electrode/molten salt interface are reported. The system investigated was modeled by the restricted primitive model of electrolyte being in contact with the charged hard wall (hard spheres of diameter d=400 pm and relative permittivity epsilon(r)=10). The temperature analysis of the mean activity coefficient gamma(+/-), heat capacity C(v) and radial distribution function, g, indicated the range of temperatures of the study. Calculations for the electrode/electrolyte interface were carried out for temperatures 1300, 1400, and 1500 K and in the range of the electrode charge densities sigma from 0.025 to 0.5 C m(-2). Singlet distribution functions showed a multilayer structure of the electrolyte in the vicinity of the electrode surface. The structure depended on the electrode charge, but not much on temperature. The capacitance curves had a parabolalike shape with the maximum located at sigma=0. This result is not consistent with the Gouy-Chapman theory, but has been confirmed by the modified Poisson-Boltzmann theory, which includes the correlation and exclusion volume effects.

[1]  Roger Parsons,et al.  The electrical double layer: recent experimental and theoretical developments , 1990 .

[2]  K. B. Oldham.  A Gouy–Chapman–Stern model of the double layer at a (metal)/(ionic liquid) interface , 2008 .

[3]  The computer simulation of the metal-molten salt interface , 1988 .

[4]  Berend Smit,et al.  Understanding molecular simulation: from algorithms to applications , 1996 .

[5]  D. Heyes,et al.  Computer simulation of molten-salt interphases. Effect of a rigid boundary and an applied electric field , 1981 .

[6]  D. Lévesque,et al.  Monte Carlo simulation of an ion-dipole mixture , 1990 .

[7]  B. Larsen,et al.  Studies in statistical mechanics of Coulombic systems. II. Ergodic problems in Monte Carlo simulations of the restricted primitive model , 1978 .

[8]  P. Madden,et al.  Molecular dynamics simulations of the liquid–vapor interface of a molten salt. II. Finite size effects and comparison to experiment , 2001 .

[9]  L. B. Bhuiyan,et al.  An improved modified Poisson–Boltzmann equation in electric-double-layer theory , 1983 .

[10]  L. Scriven,et al.  A three-component model of the electrical double layer , 1992 .

[11]  V. Vlachy,et al.  Monte Carlo simulation studies of electrolyte in mixture with a neutral component , 1997 .

[12]  W. M. Haynes.  CRC Handbook of Chemistry and Physics , 1990 .

[13]  S. Lamperski,et al.  Monte Carlo study of the electrode|solvent primitive model electrolyte interface , 2007 .

[14]  A. Kisza,et al.  The capacitance of the electric double layer of electrodes in molten salts , 2002 .

[15]  J. P. Valleau,et al.  Electrical double layers. 4. Limitations of the Gouy-Chapman theory , 1982 .

[16]  Alexei A Kornyshev,et al.  Double-layer in ionic liquids: paradigm change? , 2007, The journal of physical chemistry. B.

[17]  D. Inman,et al.  The electrical double layer in molten salts: Part 2. The double-layer capacitance , 1970 .

[18]  R. D. Shannon,et al.  Effective ionic radii in oxides and fluorides , 1969 .

[19]  J. P. Valleau,et al.  Electrical double layers. I. Monte Carlo study of a uniformly charged surface , 1980 .

[20]  M. Bazant,et al.  Steric effects in the dynamics of electrolytes at large applied voltages. I. Double-layer charging. , 2006, Physical review. E, Statistical, nonlinear, and soft matter physics.

[21]  S. Lamperski,et al.  The individual and mean activity coefficients of an electrolyte from the inverse GCMC simulation , 2007 .

[22]  P. Madden,et al.  Molecular dynamics simulations of the liquid–vapor interface of a molten salt. III. Size asymmetry effects and binary mixtures , 2002 .

[23]  Ian W. M. Smith.  The mechanism of the OH + CO reaction and the stability of the HOCO radical , 1977 .

[24]  D. Chapman,et al.  LI. A contribution to the theory of electrocapillarity , 1913 .

[25]  P. Madden,et al.  Screening at a charged surface by a molten salt , 2004 .

[26]  Douglas Henderson,et al.  Monte Carlo study of the capacitance of the double layer in a model molten salt , 1999 .

[27]  S. Lamperski,et al.  Counterion layering at high surface charge in an electric double layer. Effect of local concentration approximation , 2003 .

[28]  Claude Garrod,et al.  Statistical mechanics and thermodynamics , 1995 .

[29]  B. Larsen.  Studies in statistical mechanics of Coulombic systems. I. Equation of state for the restricted primitive model , 1976 .

[30]  A. Kisza,et al.  The capacitance of the diffuse layer of electric double layer of electrodes in molten salts , 2006 .

[31]  L. B. Bhuiyan,et al.  Comparison of the modified Poisson–Boltzmann theory with recent density functional theory and simulation results in the planar electric double layer , 2004 .

[32]  A. D. Graves.  The electrical double layer in molten salts , 1970 .

[33]  S. Lamperski,et al.  A treatment of the exclusion volume term in the inhomogeneous Poisson-Boltzmann theory for an ion-dipole mixture , 2001 .