Quantification of ionic transport within thermally-activated batteries using electron probe micro-analysis

Abstract

The transient transport of electrolytes in thermally-activated batteries is studied using electron probe micro-analysis (EPMA), demonstrating the robust capability of EPMA as a useful tool for studying and quantifying mass transport within porous materials, particularly in difficult environments where classical flow measurements are challenging. By tracking the mobility of bromine and potassium ions from the electrolyte stored within the separator into the lithium silicon anode and iron disulfide cathode, we are able to quantify the transport mechanisms and physical properties of the electrodes including permeability and tortuosity. Due to the micron to submicron scale porous structure of the initially dry anode, a fast capillary pressure driven flow is observed into the anode from which we are able to set a lower bound on the permeability of 10-1 mDarcy. The transport into the cathode is diffusion-limited because the cathode originally contained some electrolyte before activation. Using a transient one-dimensional diffusion model, we estimate the tortuosity of the cathode electrode to be 2.8 ± 0.8.

Preparation and Discharge Performance of Thin‐Film Thermal Battery

“…Therefore, unlike liquid batteries such as lithium‐ion batteries, which need to be wetted during assembly, the separator of thermal batteries can only be wetted on the surface. Because the reaction only takes place at the wetting interface, [ 16 ] in the discharge process of “near‐solid‐state” batteries, the biggest influence of thickness is to block the diffusion path of lithium‐ion (the distance from anode to cathode). [ 17 ] In addition, it is necessary to point out that the reaction core of lithium battery is that the cathode reacts with the lithium ion in the electrolyte, while the anode continuously loses electrons to supplement the lithium‐ion in the electrolyte.…”

Delamination‐Free Multifunctional Separator for Long‐Term Stability of Lithium‐Ion Batteries

“…Figure shows the surface image of the MCS after the peel‐off test of the electrode/MCS assembly and corresponding electron probe microanalysis (EPMA) mapping of elemental carbon. EPMA generates 2D maps of the elemental concentration with enhanced elemental detection of wavelength dispersive spectroscopy . The EPMA image of the MCS surface after peel‐off test shows good distribution of black and blue‐green regions throughout the investigated region.…”

High‐Temperature Solid‐State Synthesis and Electrochemical Properties of Transition Metal Sulfides for Thermal Batteries

“…Many synthesis methods for synthesizing of FeS 2 and CoS 2 have been conducted by researchers such as hydrothermal method, high-energy ball-milling method, seed induction synthesis method, and molten salt electrolysis method. [21][22][23] These methods have certain synthesis advantages, but they are not sufficient for large-scale industrialization due to the low productivity and long production cycle. The NiS 2 , as a new type of cathode material, has attracted much attention because of its lower cost than CoS 2 and higher thermal stability than FeS 2 .…”