Composition and Manufacturing Effects on Electrical Conductivity of Li/FeS₂Thermal Battery Cathodes

Abstract

Electrical conductivity is key to the performance of thermal battery cathodes. In this work we present the effects of manufacturing and processing conditions on the electrical conductivity of Li/FeS 2 thermal battery cathodes. We use finite element simulations to compute the conductivity of three-dimensional microcomputed tomography cathode microstructures and compare results to experimental impedance spectroscopy measurements. A regression analysis reveals a predictive relationship between composition, processing conditions, and electrical conductivity; a trend which is largely erased after thermally-induced deformation. The trend applies to both experimental and simulation results, although is not as apparent in simulations. This research is a step toward a more fundamental understanding of the effects of processing and composition on thermal battery component microstructure, properties, and performance.

Mesoscale Effective Property Simulations Incorporating Conductive Binder

“…[16][17][18][19] Recent advancements in mesoscale imaging techniques have enabled detailed visualization of complex electrode mesostructures, [20][21][22][23][24][25][26][27][28][29][30][31][32] allowing modeling efforts to progress to real electrode morphologies. 20,27,[33][34][35][36][37][38][39][40][41][42] To bridge the gap between mesoscale and cell-level simulations, efforts have been made to extract electrode-scale properties from mesoscale reconstructions. [43][44][45][46][47] These effective properties represent the material property value for a homogenized volume-averaged treatment of the composite electrode and are necessary to feasibly solve full-battery simulations.…”

Recent Progress in Cathode Materials for Thermal Batteries

“…However, the performance improvement is limited due to the low thermal stability and low open circuit voltage compared to other materials, and studies have been conducted to supplement these findings. [10][11][12][13][14][15] Lee et al studied the use of carbon black and carbon nanotubes on an FeS 2 cathode in Li-Si/ FeS 2 thermal batteries. 10) Discharge measurements and the calculated total polarization confirmed that the performance of the single cell improved when a carbonaceous material was added ( Fig.…”

“…The most commonly used cathode material to date is FeS 2 . In addition to studies on optimizing electrode fabrication using FeS 2 , [10][11][12][13][14][15] studies have been conducted on the use of materials such as CoS 2 , [16][17][18][19][20][21] NiS 2 , [22][23][24] NiCl 2 , [25][26][27][28] CuVO, [29][30] and others. [31][32][33] Masset et al cited the following key properties to be considered as cathode materials for thermal batteries: 4) • Redox potential: it should have a discharge potential that is compatible with the electrochemical window of the electrolyte in order to prevent oxidation.…”

The Effect of MgO‐MgF2 Synthesis Method on the Electrolyte Binding Ability in Thermal Batteries

“…The performance of magnesium oxide as an immobilizing agent has been well described in the literature . To relieve the defects in electrolytes, such as broken edges, cracks, compositional fluctuation, about 40 wt.% MgO binder in a powder form is generally added to hold the molten electrolyte . In most publications, commercially available MgO was used as an electrolyte immobilizer.…”