Probing Solid-State Interface Kinetics via Alternating Current Electrophoretic Deposition: LiFePO<sub>4</sub> Li-Metal Batteries
This work presents a comprehensive investigation into the interfacial charge storage mechanisms and lithium-ion transport behavior of Li-metal all-solid-state batteries (ASSBs) employing LiFePO<sub>4</sub> (LFP) cathodes fabricated via alternating current electrophoretic deposition (AC-E...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-06-01
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| Series: | Applied Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-3417/15/13/7120 |
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| Summary: | This work presents a comprehensive investigation into the interfacial charge storage mechanisms and lithium-ion transport behavior of Li-metal all-solid-state batteries (ASSBs) employing LiFePO<sub>4</sub> (LFP) cathodes fabricated via alternating current electrophoretic deposition (AC-EPD) and Li<sub>1.3</sub>Al<sub>0.3</sub>Ti<sub>1.7</sub>(PO<sub>4</sub>)<sub>3</sub> (LATP) as the solid-state electrolyte. We demonstrate that optimal sintering improves the LATP–LFP interfacial contact, leading to higher lithium diffusivity (~10<sup>−9</sup> cm<sup>2</sup>∙s<sup>−1</sup>) and diffusion-controlled kinetics (<i>b</i> ≈ 0.5), which directly translate to better rate capability. Structural and electrochemical analyses—including X-ray diffraction, scanning electron microscopy, cyclic voltammetry, and rate capability tests—demonstrate that the cell with LATP sintered at 900 °C delivers the highest Li-ion diffusivity (~10<sup>−9</sup> cm<sup>2</sup>∙s<sup>−1</sup>), near-ideal diffusion-controlled behavior (<i>b</i>-values ~0.5), and superior rate capability. In contrast, excessive sintering at 1000 °C led to reduced diffusivity (~10<sup>−10</sup> cm<sup>2</sup>∙s<sup>−1</sup>). The liquid electrolyte system showed higher <i>b</i>-values (~0.58), indicating the inclusion of surface capacitive behavior. The correlation between <i>b</i>-values, diffusivity, and morphology underscores the critical role of interface engineering and electrolyte processing in determining the performance of solid-state batteries. This study establishes AC-EPD as a viable and scalable method for fabricating additive-free LFP cathodes and offers new insights into the structure–property relationships governing the interfacial transport in ASSBs. |
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| ISSN: | 2076-3417 |