In Situ Probing Potassium-Ion Intercalation-Induced Amorphization in Crystalline Iron Phosphate Cathode Materials

Abstract

Na-ion and K-ion batteries are promising alternatives for large-scale energy storage due to their abundance and low cost. Intercalation of these large ions could cause irreversible structural deformation and partial to complete amorphization in the crystalline electrodes. A lack of understanding of the dynamic changes in the amorphous nanostructure during battery operation is the bottleneck for further developments. Here, we report the utilization of in-operando digital image correlation and XRD techniques to probe dynamic changes in the amorphous phase of iron phosphate during potassium ion intercalation. In-operando XRD demonstrates amorphization in the electrode’s nanostructure during the first charge and discharge cycle. Additionally, ex situ HR-TEM further confirms the amorphization after potassium-ion intercalation. An in situ strain analysis detects reversible deformations associated with redox reactions in the amorphous phases. Our approach offers new insights into the mechanism of ion intercalation in the amorphous nanostructure which are highly potent for the development of next-generation batteries.

Mechanistic Elucidation of Electronically Conductive PEDOT:PSS Tailored Binder for a Potassium‐Ion Battery Graphite Anode: Electrochemical, Mechanical, and Thermal Safety Aspects

“…Optical Expansion Experiments: A detailed description of the custom cell and experimental setup can be found in a previous publication. [89] Strain generation analysis was carried out by taking images of freestanding electrodes during electrochemical cycling. Pictures were captured with Grasshopper3 5.0 MP camera (Sony IMX250, resolution, 2448w x 2048h pixel) with 12.0X adjustable zoom lens (NAVITAR) for an effective resolution of 2.049 µm/pixel when using 2.0X setting on the adjustable zoom lens.…”

“…The detail of the custom cell was described in a previous publication in detail. [ 89 ] The electrolyte was 0.8 m KPF 6 in 1:1 EC:DEC and custom cell assembly and electrolyte preparation carried out in argon glovebox (MBraun). Arbin potentiostat/galvanostat (MSTAT21044) was used to cycle the custom battery cell.…”

Boron‐Catalyzed Graphitization Carbon Layer Enabling LiMn0.8Fe0.2PO4 Cathode Superior Kinetics and Li‐Storage Properties

“…The diffraction peaks of LiMn 0.8 Fe 0.2 PO 4 basically return to the initial position, demonstrating that it delivers excellent reversibility. [36,39] Therefore, the B-catalyzed graphitization carbon-coated LiMn 0.8 Fe 0.2 PO 4 shows a combined reaction mechanism of typical two-phase transitions of olivine structure LiMnPO 4 and the solid solution reaction, exhibiting excellent structural stability and reversibility.…”

The Coupling between Voltage Profiles and Mechanical Deformations in LAGP Solid Electrolyte During Li Plating and Stripping

“…Li1.5Al0.5Ge1.5P3O12 (LAGP) solid electrolyte is selected as a model system. DIC technique has been used to investigate reversible and irreversible strain generation in the battery electrodes due to phase transformations [14][15][16] and a formation of solid-electrolyte interface 17,18 .…”