make SEI single layer only (#4470)

* make SEI single layer only

* fix failing tests

* remove some further instances of inner & outer SEI

* shorten comment

* fix failing tests

* switch examples to IDAKLU solver for robustness

* fix typo with SEI OCP

* revert to U_SEI = 0.4 V, except O'Kane2022 where beta_inner = 0

* change U_SEI in example to avoid simulation to break (replicates old parameters)

* update CHANGELOG (and sort older entries)

* remove duplicated entry from CHANGELOG

* Update src/pybamm/models/submodels/interface/sei/sei_growth.py

* revert some parameter changes as suggested by Simon

* reduce SEI diffusivity to 2 significant digits (used to be 16)

* Fix changelog

---------

Co-authored-by: Ferran Brosa Planella <Ferran.Brosa-Planella@warwick.ac.uk>
Co-authored-by: Eric G. Kratz <kratman@users.noreply.github.com>
Co-authored-by: kratman <kratmandu@gmail.com>

CHANGELOG.md

@@ -1,5 +1,9 @@
 # [Unreleased](https://github.com/pybamm-team/PyBaMM/)
 
+## Breaking changes
+
+- Double-layer SEI models have been removed (with the corresponding parameters). All models assume now a single SEI layer. ([#4470](https://github.com/pybamm-team/PyBaMM/pull/4470))
+
 # [v24.11.0](https://github.com/pybamm-team/PyBaMM/tree/v24.11.0) - 2024-11-20
 
 ## Features

docs/source/examples/notebooks/batch_study.ipynb

@@ -501,15 +501,15 @@
     "    \"Mohtat2020_3\": pybamm.ParameterValues(\"Mohtat2020\"),\n",
     "}\n",
     "\n",
-    "# different values for the parameter \"Inner SEI open-circuit potential [V]\"\n",
-    "inner_sei_oc_v_values = [2.0e-4, 2.7e-4, 3.4e-4]\n",
+    "# different values for the parameter \"SEI open-circuit potential [V]\"\n",
+    "sei_oc_v_values = [2.0e-4, 2.7e-4, 3.4e-4]\n",
     "\n",
-    "# updating the value of \"Inner SEI open-circuit potential [V]\" in all the dictionary items\n",
-    "for _, v, inner_sei_oc_v in zip(\n",
-    "    parameter_values.keys(), parameter_values.values(), inner_sei_oc_v_values\n",
+    "# updating the value of \"SEI open-circuit potential [V]\" in all the dictionary items\n",
+    "for _, v, sei_oc_v in zip(\n",
+    "    parameter_values.keys(), parameter_values.values(), sei_oc_v_values\n",
     "):\n",
     "    v.update(\n",
-    "        {\"Inner SEI open-circuit potential [V]\": inner_sei_oc_v},\n",
+    "        {\"SEI open-circuit potential [V]\": sei_oc_v},\n",
     "    )\n",
     "\n",
     "# creating a Single Particle Model with \"electron-mitigation limited\" SEI\n",
@@ -527,8 +527,8 @@
     "batch_study.solve(initial_soc=1)\n",
     "\n",
     "labels = [\n",
-    "    f\"Inner SEI open-circuit potential [V]: {inner_sei_oc_v}\"\n",
-    "    for inner_sei_oc_v in inner_sei_oc_v_values\n",
+    "    f\"SEI open-circuit potential [V]: {inner_sei_oc_v}\"\n",
+    "    for inner_sei_oc_v in sei_oc_v_values\n",
     "]\n",
     "batch_study.plot(labels=labels)"
    ]

docs/source/examples/notebooks/getting_started/tutorial-4-setting-parameter-values.ipynb

@@ -656,7 +656,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "env",
+   "display_name": "venv",
    "language": "python",
    "name": "python3"
   },
@@ -670,7 +670,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.10.12"
+   "version": "3.11.6"
   },
   "toc": {
    "base_numbering": 1,

docs/source/examples/notebooks/models/loss_of_active_materials.ipynb

@@ -632,7 +632,7 @@
     "# Changing secondary SEI solvent diffusivity to show different degradation between phases\n",
     "parameter_values.update(\n",
     "    {\n",
-    "        \"Secondary: Outer SEI solvent diffusivity [m2.s-1]\": 2.5000000000000002e-24,\n",
+    "        \"Secondary: SEI solvent diffusivity [m2.s-1]\": 2.5e-24,\n",
     "    }\n",
     ")\n",
     "\n",

examples/scripts/calendar_ageing.py

@@ -25,7 +25,7 @@
 
     sim = pb.Simulation(model, parameter_values=parameter_values)
 
-    solver = pb.CasadiSolver(mode="fast")
+    solver = pb.IDAKLUSolver()
 
     years = 30
     days = years * 365

examples/scripts/rate_capability.py

@@ -16,9 +16,8 @@
 for i, C_rate in enumerate(C_rates):
     experiment = pybamm.Experiment(
         [f"Discharge at {C_rate:.4f}C until 3.2V"],
-        period=f"{10 / C_rate:.4f} seconds",
     )
-    sim = pybamm.Simulation(model, experiment=experiment, solver=pybamm.CasadiSolver())
+    sim = pybamm.Simulation(model, experiment=experiment, solver=pybamm.IDAKLUSolver())
     sim.solve()
 
     time = sim.solution["Time [s]"].entries

src/pybamm/input/parameters/lithium_ion/Ai2020.py

@@ -534,26 +534,20 @@ def get_parameter_values():
         "chemistry": "lithium_ion",
         # sei
         "Ratio of lithium moles to SEI moles": 2.0,
-        "Inner SEI reaction proportion": 0.5,
-        "Inner SEI partial molar volume [m3.mol-1]": 9.585e-05,
-        "Outer SEI partial molar volume [m3.mol-1]": 9.585e-05,
+        "SEI partial molar volume [m3.mol-1]": 9.585e-05,
         "SEI reaction exchange current density [A.m-2]": 1.5e-07,
         "SEI resistivity [Ohm.m]": 200000.0,
-        "Outer SEI solvent diffusivity [m2.s-1]": 2.5000000000000002e-22,
+        "SEI solvent diffusivity [m2.s-1]": 2.5e-22,
         "Bulk solvent concentration [mol.m-3]": 2636.0,
-        "Inner SEI open-circuit potential [V]": 0.1,
-        "Outer SEI open-circuit potential [V]": 0.8,
-        "Inner SEI electron conductivity [S.m-1]": 8.95e-14,
-        "Inner SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
+        "SEI open-circuit potential [V]": 0.4,
+        "SEI electron conductivity [S.m-1]": 8.95e-14,
+        "SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
         "Lithium interstitial reference concentration [mol.m-3]": 15.0,
-        "Initial inner SEI thickness [m]": 2.5e-09,
-        "Initial outer SEI thickness [m]": 2.5e-09,
-        "Initial inner SEI on cracks thickness [m]": 2.5e-13,  # avoid division by zero
-        "Initial outer SEI on cracks thickness [m]": 2.5e-13,  # avoid division by zero
+        "Initial SEI thickness [m]": 5e-09,
+        "Initial SEI on cracks thickness [m]": 5e-13,  # avoid division by zero
         "EC initial concentration in electrolyte [mol.m-3]": 4541.0,
         "EC diffusivity [m2.s-1]": 2e-18,
         "SEI kinetic rate constant [m.s-1]": 1e-12,
-        "SEI open-circuit potential [V]": 0.4,
         "SEI growth activation energy [J.mol-1]": 0.0,
         "Negative electrode reaction-driven LAM factor [m3.mol-1]": 0.0,
         "Positive electrode reaction-driven LAM factor [m3.mol-1]": 0.0,

src/pybamm/input/parameters/lithium_ion/Chen2020.py

@@ -227,24 +227,19 @@ def get_parameter_values():
         "chemistry": "lithium_ion",
         # sei
         "Ratio of lithium moles to SEI moles": 2.0,
-        "Inner SEI reaction proportion": 0.5,
-        "Inner SEI partial molar volume [m3.mol-1]": 9.585e-05,
-        "Outer SEI partial molar volume [m3.mol-1]": 9.585e-05,
+        "SEI partial molar volume [m3.mol-1]": 9.585e-05,
         "SEI reaction exchange current density [A.m-2]": 1.5e-07,
         "SEI resistivity [Ohm.m]": 200000.0,
-        "Outer SEI solvent diffusivity [m2.s-1]": 2.5000000000000002e-22,
+        "SEI solvent diffusivity [m2.s-1]": 2.5e-22,
         "Bulk solvent concentration [mol.m-3]": 2636.0,
-        "Inner SEI open-circuit potential [V]": 0.1,
-        "Outer SEI open-circuit potential [V]": 0.8,
-        "Inner SEI electron conductivity [S.m-1]": 8.95e-14,
-        "Inner SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
+        "SEI open-circuit potential [V]": 0.4,
+        "SEI electron conductivity [S.m-1]": 8.95e-14,
+        "SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
         "Lithium interstitial reference concentration [mol.m-3]": 15.0,
-        "Initial inner SEI thickness [m]": 2.5e-09,
-        "Initial outer SEI thickness [m]": 2.5e-09,
+        "Initial SEI thickness [m]": 5e-09,
         "EC initial concentration in electrolyte [mol.m-3]": 4541.0,
         "EC diffusivity [m2.s-1]": 2e-18,
         "SEI kinetic rate constant [m.s-1]": 1e-12,
-        "SEI open-circuit potential [V]": 0.4,
         "SEI growth activation energy [J.mol-1]": 0.0,
         "Negative electrode reaction-driven LAM factor [m3.mol-1]": 0.0,
         "Positive electrode reaction-driven LAM factor [m3.mol-1]": 0.0,

src/pybamm/input/parameters/lithium_ion/Chen2020_composite.py

@@ -328,44 +328,34 @@ def get_parameter_values():
         "chemistry": "lithium_ion",
         # sei
         "Primary: Ratio of lithium moles to SEI moles": 2.0,
-        "Primary: Inner SEI reaction proportion": 0.5,
-        "Primary: Inner SEI partial molar volume [m3.mol-1]": 9.585e-05,
-        "Primary: Outer SEI partial molar volume [m3.mol-1]": 9.585e-05,
+        "Primary: SEI partial molar volume [m3.mol-1]": 9.585e-05,
         "Primary: SEI reaction exchange current density [A.m-2]": 1.5e-07,
         "Primary: SEI resistivity [Ohm.m]": 200000.0,
-        "Primary: Outer SEI solvent diffusivity [m2.s-1]": 2.5000000000000002e-22,
+        "Primary: SEI solvent diffusivity [m2.s-1]": 2.5e-22,
         "Primary: Bulk solvent concentration [mol.m-3]": 2636.0,
-        "Primary: Inner SEI open-circuit potential [V]": 0.1,
-        "Primary: Outer SEI open-circuit potential [V]": 0.8,
-        "Primary: Inner SEI electron conductivity [S.m-1]": 8.95e-14,
-        "Primary: Inner SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
+        "Primary: SEI open-circuit potential [V]": 0.4,
+        "Primary: SEI electron conductivity [S.m-1]": 8.95e-14,
+        "Primary: SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
         "Primary: Lithium interstitial reference concentration [mol.m-3]": 15.0,
-        "Primary: Initial inner SEI thickness [m]": 2.5e-09,
-        "Primary: Initial outer SEI thickness [m]": 2.5e-09,
+        "Primary: Initial SEI thickness [m]": 5e-09,
         "Primary: EC initial concentration in electrolyte [mol.m-3]": 4541.0,
         "Primary: EC diffusivity [m2.s-1]": 2e-18,
         "Primary: SEI kinetic rate constant [m.s-1]": 1e-12,
-        "Primary: SEI open-circuit potential [V]": 0.4,
         "Primary: SEI growth activation energy [J.mol-1]": 0.0,
         "Secondary: Ratio of lithium moles to SEI moles": 2.0,
-        "Secondary: Inner SEI reaction proportion": 0.5,
-        "Secondary: Inner SEI partial molar volume [m3.mol-1]": 9.585e-05,
-        "Secondary: Outer SEI partial molar volume [m3.mol-1]": 9.585e-05,
+        "Secondary: SEI partial molar volume [m3.mol-1]": 9.585e-05,
         "Secondary: SEI reaction exchange current density [A.m-2]": 1.5e-07,
         "Secondary: SEI resistivity [Ohm.m]": 200000.0,
-        "Secondary: Outer SEI solvent diffusivity [m2.s-1]": 2.5000000000000002e-22,
+        "Secondary: SEI solvent diffusivity [m2.s-1]": 2.5e-22,
         "Secondary: Bulk solvent concentration [mol.m-3]": 2636.0,
-        "Secondary: Inner SEI open-circuit potential [V]": 0.1,
-        "Secondary: Outer SEI open-circuit potential [V]": 0.8,
-        "Secondary: Inner SEI electron conductivity [S.m-1]": 8.95e-14,
-        "Secondary: Inner SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
+        "Secondary: SEI open-circuit potential [V]": 0.4,
+        "Secondary: SEI electron conductivity [S.m-1]": 8.95e-14,
+        "Secondary: SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
         "Secondary: Lithium interstitial reference concentration [mol.m-3]": 15.0,
-        "Secondary: Initial inner SEI thickness [m]": 2.5e-09,
-        "Secondary: Initial outer SEI thickness [m]": 2.5e-09,
+        "Secondary: Initial SEI thickness [m]": 5e-09,
         "Secondary: EC initial concentration in electrolyte [mol.m-3]": 4541.0,
         "Secondary: EC diffusivity [m2.s-1]": 2e-18,
         "Secondary: SEI kinetic rate constant [m.s-1]": 1e-12,
-        "Secondary: SEI open-circuit potential [V]": 0.4,
         "Secondary: SEI growth activation energy [J.mol-1]": 0.0,
         "Positive electrode reaction-driven LAM factor [m3.mol-1]": 0.0,
         # cell

src/pybamm/input/parameters/lithium_ion/Ecker2015.py

@@ -375,9 +375,7 @@ def SEI_limited_dead_lithium_OKane2022(L_sei):
     """
 
     gamma_0 = pybamm.Parameter("Dead lithium decay constant [s-1]")
-    L_inner_0 = pybamm.Parameter("Initial inner SEI thickness [m]")
-    L_outer_0 = pybamm.Parameter("Initial outer SEI thickness [m]")
-    L_sei_0 = L_inner_0 + L_outer_0
+    L_sei_0 = pybamm.Parameter("Initial SEI thickness [m]")
 
     gamma = gamma_0 * L_sei_0 / L_sei
 
@@ -514,24 +512,19 @@ def get_parameter_values():
         "Dead lithium decay rate [s-1]": SEI_limited_dead_lithium_OKane2022,
         # sei
         "Ratio of lithium moles to SEI moles": 2.0,
-        "Inner SEI reaction proportion": 0.5,
-        "Inner SEI partial molar volume [m3.mol-1]": 9.585e-05,
-        "Outer SEI partial molar volume [m3.mol-1]": 9.585e-05,
+        "SEI partial molar volume [m3.mol-1]": 9.585e-05,
         "SEI reaction exchange current density [A.m-2]": 1.5e-07,
         "SEI resistivity [Ohm.m]": 200000.0,
-        "Outer SEI solvent diffusivity [m2.s-1]": 2.5000000000000002e-22,
+        "SEI solvent diffusivity [m2.s-1]": 2.5e-22,
         "Bulk solvent concentration [mol.m-3]": 2636.0,
-        "Inner SEI open-circuit potential [V]": 0.1,
-        "Outer SEI open-circuit potential [V]": 0.8,
-        "Inner SEI electron conductivity [S.m-1]": 8.95e-14,
-        "Inner SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
+        "SEI open-circuit potential [V]": 0.4,
+        "SEI electron conductivity [S.m-1]": 8.95e-14,
+        "SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
         "Lithium interstitial reference concentration [mol.m-3]": 15.0,
-        "Initial inner SEI thickness [m]": 2.5e-09,
-        "Initial outer SEI thickness [m]": 2.5e-09,
+        "Initial SEI thickness [m]": 5e-09,
         "EC initial concentration in electrolyte [mol.m-3]": 4541.0,
         "EC diffusivity [m2.s-1]": 2e-18,
         "SEI kinetic rate constant [m.s-1]": 1e-12,
-        "SEI open-circuit potential [V]": 0.4,
         "SEI growth activation energy [J.mol-1]": 0.0,
         "Negative electrode reaction-driven LAM factor [m3.mol-1]": 0.0,
         "Positive electrode reaction-driven LAM factor [m3.mol-1]": 0.0,

src/pybamm/input/parameters/lithium_ion/Ecker2015_graphite_halfcell.py

@@ -262,9 +262,7 @@ def SEI_limited_dead_lithium_OKane2022(L_sei):
     """
 
     gamma_0 = pybamm.Parameter("Dead lithium decay constant [s-1]")
-    L_inner_0 = pybamm.Parameter("Initial inner SEI thickness [m]")
-    L_outer_0 = pybamm.Parameter("Initial outer SEI thickness [m]")
-    L_sei_0 = L_inner_0 + L_outer_0
+    L_sei_0 = pybamm.Parameter("Initial SEI thickness [m]")
 
     gamma = gamma_0 * L_sei_0 / L_sei
 
@@ -436,24 +434,19 @@ def get_parameter_values():
         "Dead lithium decay rate [s-1]": SEI_limited_dead_lithium_OKane2022,
         # sei
         "Ratio of lithium moles to SEI moles": 2.0,
-        "Inner SEI reaction proportion": 0.5,
-        "Inner SEI partial molar volume [m3.mol-1]": 9.585e-05,
-        "Outer SEI partial molar volume [m3.mol-1]": 9.585e-05,
+        "SEI partial molar volume [m3.mol-1]": 9.585e-05,
         "SEI reaction exchange current density [A.m-2]": 1.5e-07,
         "SEI resistivity [Ohm.m]": 200000.0,
-        "Outer SEI solvent diffusivity [m2.s-1]": 2.5000000000000002e-22,
+        "SEI solvent diffusivity [m2.s-1]": 2.5e-22,
         "Bulk solvent concentration [mol.m-3]": 2636.0,
-        "Inner SEI open-circuit potential [V]": 0.1,
-        "Outer SEI open-circuit potential [V]": 0.8,
-        "Inner SEI electron conductivity [S.m-1]": 8.95e-14,
-        "Inner SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
+        "SEI open-circuit potential [V]": 0.4,
+        "SEI electron conductivity [S.m-1]": 8.95e-14,
+        "SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
         "Lithium interstitial reference concentration [mol.m-3]": 15.0,
-        "Initial inner SEI thickness [m]": 2.5e-09,
-        "Initial outer SEI thickness [m]": 2.5e-09,
+        "Initial SEI thickness [m]": 5e-09,
         "EC initial concentration in electrolyte [mol.m-3]": 4541.0,
         "EC diffusivity [m2.s-1]": 2e-18,
         "SEI kinetic rate constant [m.s-1]": 1e-12,
-        "SEI open-circuit potential [V]": 0.4,
         "SEI growth activation energy [J.mol-1]": 0.0,
         "Positive electrode reaction-driven LAM factor [m3.mol-1]": 0.0,
         # cell

src/pybamm/input/parameters/lithium_ion/Marquis2019.py

@@ -352,25 +352,20 @@ def get_parameter_values():
         "chemistry": "lithium_ion",
         # sei
         "Ratio of lithium moles to SEI moles": 2.0,
-        "Inner SEI reaction proportion": 0.5,
-        "Inner SEI partial molar volume [m3.mol-1]": 9.585e-05,
-        "Outer SEI partial molar volume [m3.mol-1]": 9.585e-05,
+        "SEI partial molar volume [m3.mol-1]": 9.585e-05,
         "SEI growth transfer coefficient": 0.5,
         "SEI reaction exchange current density [A.m-2]": 1.5e-07,
         "SEI resistivity [Ohm.m]": 200000.0,
-        "Outer SEI solvent diffusivity [m2.s-1]": 2.5000000000000002e-22,
+        "SEI solvent diffusivity [m2.s-1]": 2.5e-22,
         "Bulk solvent concentration [mol.m-3]": 2636.0,
-        "Inner SEI open-circuit potential [V]": 0.1,
-        "Outer SEI open-circuit potential [V]": 0.8,
-        "Inner SEI electron conductivity [S.m-1]": 8.95e-14,
-        "Inner SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
+        "SEI open-circuit potential [V]": 0.4,
+        "SEI electron conductivity [S.m-1]": 8.95e-14,
+        "SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
         "Lithium interstitial reference concentration [mol.m-3]": 15.0,
-        "Initial inner SEI thickness [m]": 2.5e-09,
-        "Initial outer SEI thickness [m]": 2.5e-09,
+        "Initial SEI thickness [m]": 5e-09,
         "EC initial concentration in electrolyte [mol.m-3]": 4541.0,
         "EC diffusivity [m2.s-1]": 2e-18,
         "SEI kinetic rate constant [m.s-1]": 1e-12,
-        "SEI open-circuit potential [V]": 0.4,
         "SEI growth activation energy [J.mol-1]": 0.0,
         "Negative electrode reaction-driven LAM factor [m3.mol-1]": 0.0,
         "Positive electrode reaction-driven LAM factor [m3.mol-1]": 0.0,

src/pybamm/input/parameters/lithium_ion/Mohtat2020.py

@@ -344,24 +344,19 @@ def get_parameter_values():
         "Lithium plating transfer coefficient": 0.7,
         # sei
         "Ratio of lithium moles to SEI moles": 2.0,
-        "Inner SEI reaction proportion": 0.5,
-        "Inner SEI partial molar volume [m3.mol-1]": 9.585e-05,
-        "Outer SEI partial molar volume [m3.mol-1]": 9.585e-05,
+        "SEI partial molar volume [m3.mol-1]": 9.585e-05,
         "SEI reaction exchange current density [A.m-2]": 1.5e-07,
         "SEI resistivity [Ohm.m]": 200000.0,
-        "Outer SEI solvent diffusivity [m2.s-1]": 2.5000000000000002e-22,
+        "SEI solvent diffusivity [m2.s-1]": 2.5e-22,
         "Bulk solvent concentration [mol.m-3]": 2636.0,
-        "Inner SEI open-circuit potential [V]": 0.1,
-        "Outer SEI open-circuit potential [V]": 0.8,
-        "Inner SEI electron conductivity [S.m-1]": 8.95e-14,
-        "Inner SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
+        "SEI open-circuit potential [V]": 0.4,
+        "SEI electron conductivity [S.m-1]": 8.95e-14,
+        "SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
         "Lithium interstitial reference concentration [mol.m-3]": 15.0,
-        "Initial inner SEI thickness [m]": 2.5e-09,
-        "Initial outer SEI thickness [m]": 2.5e-09,
+        "Initial SEI thickness [m]": 5e-09,
         "EC initial concentration in electrolyte [mol.m-3]": 4541.0,
         "EC diffusivity [m2.s-1]": 2e-18,
         "SEI kinetic rate constant [m.s-1]": 1e-12,
-        "SEI open-circuit potential [V]": 0.4,
         "SEI growth activation energy [J.mol-1]": 0.0,
         "Negative electrode reaction-driven LAM factor [m3.mol-1]": 0.0,
         "Positive electrode reaction-driven LAM factor [m3.mol-1]": 0.0,

src/pybamm/input/parameters/lithium_ion/NCA_Kim2011.py

@@ -311,24 +311,19 @@ def get_parameter_values():
         "chemistry": "lithium_ion",
         # sei
         "Ratio of lithium moles to SEI moles": 2.0,
-        "Inner SEI reaction proportion": 0.5,
-        "Inner SEI partial molar volume [m3.mol-1]": 9.585e-05,
-        "Outer SEI partial molar volume [m3.mol-1]": 9.585e-05,
+        "SEI partial molar volume [m3.mol-1]": 9.585e-05,
         "SEI reaction exchange current density [A.m-2]": 1.5e-07,
         "SEI resistivity [Ohm.m]": 200000.0,
-        "Outer SEI solvent diffusivity [m2.s-1]": 2.5000000000000002e-22,
+        "SEI solvent diffusivity [m2.s-1]": 2.5e-22,
         "Bulk solvent concentration [mol.m-3]": 2636.0,
-        "Inner SEI open-circuit potential [V]": 0.1,
-        "Outer SEI open-circuit potential [V]": 0.8,
-        "Inner SEI electron conductivity [S.m-1]": 8.95e-14,
-        "Inner SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
+        "SEI open-circuit potential [V]": 0.4,
+        "SEI electron conductivity [S.m-1]": 8.95e-14,
+        "SEI lithium interstitial diffusivity [m2.s-1]": 1e-20,
         "Lithium interstitial reference concentration [mol.m-3]": 15.0,
-        "Initial inner SEI thickness [m]": 2.5e-09,
-        "Initial outer SEI thickness [m]": 2.5e-09,
+        "Initial SEI thickness [m]": 5e-09,
         "EC initial concentration in electrolyte [mol.m-3]": 4541.0,
         "EC diffusivity [m2.s-1]": 2e-18,
         "SEI kinetic rate constant [m.s-1]": 1e-12,
-        "SEI open-circuit potential [V]": 0.4,
         "SEI growth activation energy [J.mol-1]": 0.0,
         "Negative electrode reaction-driven LAM factor [m3.mol-1]": 0.0,
         "Positive electrode reaction-driven LAM factor [m3.mol-1]": 0.0,