Struct ElectrodeKinetics 

pub struct ElectrodeKinetics {
    pub i0: f64,
    pub alpha_a: f64,
    pub alpha_c: f64,
    pub temperature: f64,
    pub n_electrons: usize,
}

Electrode kinetics using the Butler-Volmer formulation.

Computes exchange current density, Tafel slope, and EIS (electrochemical impedance spectroscopy) charge-transfer resistance.

Fields

i0: f64

Exchange current density [A/m²].

alpha_a: f64

Anodic charge-transfer coefficient (dimensionless).

alpha_c: f64

Cathodic charge-transfer coefficient (dimensionless).

temperature: f64

Temperature [K].

n_electrons: usize

Number of electrons transferred per reaction step.

Implementations

impl ElectrodeKinetics

pub fn new( i0: f64, alpha_a: f64, alpha_c: f64, temperature: f64, n_electrons: usize, ) -> Self

Construct a new ElectrodeKinetics.

pub fn symmetric(i0: f64, temperature: f64) -> Self

Construct with symmetric transfer coefficients (α_a = α_c = 0.5).

pub fn current_density(&self, eta: f64) -> f64

Butler-Volmer current density [A/m²] at overpotential eta [V].

j = i₀ × (exp(αa·F·η / (R·T)) − exp(−αc·F·η / (R·T)))

pub fn anodic_tafel_slope(&self) -> f64

Anodic Tafel slope [V/decade].

b_a = 2.303 R T / (α_a F)

pub fn cathodic_tafel_slope(&self) -> f64

Cathodic Tafel slope [V/decade].

b_c = 2.303 R T / (α_c F)

pub fn charge_transfer_resistance(&self) -> f64

Linearised charge-transfer resistance [Ω·m²] (valid for small η).

From linearisation of Butler-Volmer: R_ct = R T / (n F i₀)

pub fn eis_impedance(&self, omega: f64) -> (f64, f64)

EIS impedance at angular frequency omega [rad/s].

Returns (Z_real, Z_imag) [Ω·m²] using the Randles circuit approximation:

• Charge-transfer resistance R_ct in parallel with double-layer capacitance C_dl
• Z = R_ct / (1 + (ω R_ct C_dl)²) (real) and -ω R_ct² C_dl / (1 + (ω R_ct C_dl)²) (imag)

Assumes C_dl = 0.2 F/m² (typical double-layer capacitance).

pub fn eis_magnitude(&self, omega: f64) -> f64

EIS impedance magnitude [Ω·m²] at angular frequency omega.

pub fn tafel_overpotential_anodic(&self, j: f64) -> f64

Overpotential [V] required to achieve current density j [A/m²].

Uses high-overpotential Tafel approximation (anodic branch): η ≈ b_a × log10(j / i₀) for large positive j.

pub fn nernst_correction(&self, e_ref: f64, c_ratio: f64) -> f64

Open-circuit potential correction (Nernst) [V].

E = E_ref − (R T / n F) ln(c_ox/c_red) where c_ratio = c_ox/c_red.

Trait Implementations

impl Clone for ElectrodeKinetics

fn clone(&self) -> ElectrodeKinetics

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ElectrodeKinetics

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.