Abstract
Bilayered vanadium oxides (BVOs) are promising cathode materials for beyond-Li-ion batteries due to their tunable chemistries and high theoretical capacities. However, the large size of beyond-Li+ ions limits electrochemical cycling and rate capability of BVO electrodes. Recent reports of MXene-derived BVOs with nanoscale flower-like morphology have shown improved electrochemical stability at high rates up to 5C in nonaqueous lithium-ion batteries. Here, we report how morphological stabilization can lead to improved rate capability in potassium-ion batteries (PIBs) through the synthesis and electrochemical characterization of MXene-derived K-preintercalated BVOs (MD-KVOs), which were derived from two V2CTx precursor materials prepared using two different etching protocols. We show that the etching conditions affect the surface chemistry of the MXene, which plays a role in the MXene-to-oxide transformation process. MXene derived from a milder etchant transformed into a nanoflower MD-KVO with two-dimensional (2D) nanosheet petals (KVO-DMAE) while a more aggressive etchant produced a MXene that transformed into a MD-KVO with one-dimensional (1D) nanorod morphology (KVO-CMAE). Electrochemical cycling of the produced MD-KVOs after drying at 200 °C under vacuum (KVO-DMAE-200 and KVO-CMAE-200) in PIBs showed that electrochemical stability of MD-KVO at high rates improved through the morphological stabilization of 2D particles combined with the control of interlayer water and K+ ion content. Structure refinement of KVO-DMAE-200 further corroborates the behavior observed during K+ ion cycling, connecting structural and compositional characteristics to the improved rate capability. This work demonstrates how proper synthetic methodology can cause downstream effects in the control of structure, chemical composition, and morphology of nanostructured layered oxide materials, which is necessary for development of future materials for beyond-Li-ion battery technologies.
| Original language | English |
|---|---|
| Pages (from-to) | 7582-7595 |
| Number of pages | 14 |
| Journal | ACS Applied Nano Materials |
| Volume | 8 |
| Issue number | 15 |
| DOIs | |
| State | Published - Apr 18 2025 |
Funding
This work was supported by the National Science Foundation grant DMR-2106445. We thank Prof. Yury Gogotsi and Dr. Christopher Shuck* (A.J. Drexel Nanomaterials Institute, Drexel University) for providing MAX phase materials and for scientific discussions. We are grateful to Prof. Kevin Owens (Department of Chemistry, Drexel University) for providing access to atomic absorption spectroscopy characterization in the Instrumental Analytical Laboratory. We acknowledge the Materials Characterization Core at Drexel University for providing access to XRD, SEM, and XPS characterization. We appreciate the insights provided by Geetha Valurouthu regarding MXene XPS analysis. We thank Casey Durso for advice on the synthesis schematic. The scanning transmission electron microscopy portion of this research was supported by the Center for Nanophase Materials Sciences (CNMS), which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory. This research used the Pair Distribution Function (PDF, 28-ID-1) beamline of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. *Dr. Shuck is currently at Rutgers University
Keywords
- K-ion batteries
- MAX phase etchant composition
- MXene-derived oxides
- charge storage mechanism
- chemically preintercalated bilayered vanadium oxides
- morphological stabilization