A Three-Dimensional Multiscale Simulation Framework for Nickel-Tungsten Electrodeposition in Porous Electrodes

Abstract

Alloy electrodeposition within porous electrodes is governed by strongly coupled transport, kinetics, and geometry, yet these interactions remain poorly understood beyond simplified planar or two-dimensional descriptions. This study presents a three-dimensional multiscale simulation framework, combined with targeted experiments, to resolve the spatial distribution of current density, deposit thickness, and alloy composition during nickel-tungsten electrodeposition in porous carbon cloth. The simulation connects a macro-scale potential description of the electroplating cell to a micro-scale multi-ion transport and reaction formulation that explicitly captures competitive metal deposition within the fiber network. The simulations reveal how macroscopic current partitioning and local transport limitations jointly give rise to pronounced thickness and tungsten composition gradients throughout the porous architecture. Experimental electron microscopy and compositional analysis support these predicted spatial trends across length scales. By directly linking current distribution to local alloy formation in three dimensions, this work provides general insight into the fundamental mechanisms governing induced alloy co-deposition in porous electrodes, extending beyond the specific nickel-tungsten system.