Stereolithography 3D printing for vanadium redox flow battery: Electrolyte compatibility and watertightness of 3D-printed parts

Document Type

Article

Source of Publication

Next Materials

Publication Date

1-1-2025

Abstract

Additive manufacturing or 3D printing offers a fast and convenient way of fabricating parts. The additive manufacturing method can create not only complex (intricate) part structures (geometries), which are not possible or very expensive if using conventional subtractive manufacturing methods, but also to create parts with significantly less material’s waste compared to conventional subtractive manufacturing methods, which is potentially an excellent benefit for the 3D-printed parts’ life-cycle assessment to be environmentally friendly. Stereolithography (SLA) is a promising method for creating parts for vanadium redox flow batteries (VRFB), as SLA produces watertight and isotropic parts, unlike those made by as-printed fused filament fabrication (FFF) technology. Previous studies lack systematic investigation of material compatibility of SLA 3D-printed parts subjected to VRFB electrolyte or sulfuric acid. Herein, we tested the chemical compatibility, tensile mechanical strength, and swelling after immersion to 6.0 M sulfuric acid (H2SO4) solution, following ASTM D543 standard for testing the resistance of plastics to chemical reagents, as well as the watertightness of test specimens, which were 3D-printed from a feedstock of High-Temp-V2 resin (Formlabs, USA). We found no significant change in the material dimension, weight, and tensile strength between pristine and post-submerged specimens. In another experiment utilizing 1200 ml/min of VRFB electrolyte (51 % V3+ and 49 % V4+ + 2 mol L−1 H2SO4) on one side and 50 ml/min of de-ionized water (DI water) on the other side, we found the SLA 3D-printed part can withstand the pressure from the flowing liquids, and is watertight with no major leakage; however, we observed an increase in water conductivity (from 1.4 µS/cm to 8.4 µS/cm after 96 hours) due to small amount of H+ ion crossed through the 300-micrometer-thickness material, as evidenced from the pH increase of the DI water. Given the apparent slow rate of transfer (the ionic-conductivity increment is very low, which is four order-of-magnitude smaller compared to that of the VRFB electrolyte at 228.8 mS/cm), it would take significantly large timescales to detect the equilibrium concentration for both sides. Utilizing this study’s valuable information for applying SLA 3D-printed material for VRFB systems, we demonstrated producing complex specialized / customized designs for VRFB, such as 3D-printed flow frame, 3D-printed bespoke sensor mounting, and 3D-printed customized tank. We also observed that translucent 3D-printed parts are useful for quick visual inspection of electrolyte flow for VRFB troubleshooting and diagnosis.

ISSN

2949-8228

Publisher

Elsevier BV

Volume

6

First Page

100317

Last Page

100317

Disciplines

Engineering

Keywords

Additive manufacturing, Stereolithography, Vanadium redox flow battery, Electrolyte compatibility, Watertightness

Indexed in Scopus

no

Open Access

no

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