Atomic-scale investigation of the reversible α- to ω-phase lithium ion charge – discharge characteristics of electrodeposited vanadium pentoxide nanobelts
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2022-01-01 |
| Journal | Journal of Materials Chemistry A |
| Authors | Haytham E. M. Hussein, Richard Beanland, Ana M. Sánchez, David Walker, Marc Walker |
| Institutions | University of Warwick |
| Citations | 12 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: MPCVD Diamond for Advanced Battery Cathode Research
Section titled “Technical Documentation & Analysis: MPCVD Diamond for Advanced Battery Cathode Research”Executive Summary
Section titled “Executive Summary”This research successfully demonstrates the synthesis and reversible cycling of Vanadium Pentoxide ($\text{V}_2\text{O}_5$) nanobelts (NBs) using electrodeposition on Boron-Doped Diamond (BDD) electrodes. The findings validate BDD as a critical material platform for next-generation battery research.
- BDD Criticality: High-grade BDD electrodes were essential to suppress water oxidation, enabling the electrochemical synthesis of amorphous $\text{V}_2\text{O}_5$ NBs in a mixed aqueous/aprotic solvent system.
- Material Synthesis: Amorphous $\text{V}_2\text{O}_5$ NBs were crystallized into the $\alpha$-phase via thermal annealing at $350^\circ\text{C}$ (optimal temperature confirmed by in situ TEM heating).
- High Capacity: The material achieved a maximum specific capacity of $440 \text{mAh g}^{-1}$ during the first discharge cycle, consistent with the incorporation of three lithium ions per unit cell ($\omega-\text{Li}_3\text{V}_2\text{O}_5$ formation).
- Structural Reversibility: The study confirmed the challenging, yet reversible, structural transition between the layered $\alpha-\text{V}_2\text{O}_5$ phase and the rock-salt $\omega-\text{Li}_3\text{V}_2\text{O}_5$ phase over a full charge-discharge cycle.
- Atomic Insight: Aberration-Corrected STEM (ac-STEM) provided atomic-scale visualization of the phase transitions and the formation of a thin (1-2 nm) rock-salt VO surface layer on the pristine material.
- 6CCVD Value Proposition: 6CCVD provides the high-quality, custom-doped BDD substrates and specialized metalization required to replicate and advance this cutting-edge hybrid battery research.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| Electrode Material | Boron-Doped Diamond (BDD) | N/A | Used for $\text{V}_2\text{O}_5$ electrodeposition |
| BDD Dopant Level | $\sim 3 \times 10^{20}$ | B atoms per $\text{cm}^{3}$ | High conductivity required for electrochemical stability |
| BDD Thickness (TEM) | 80 | µm | Used for in situ TEM/SAED studies |
| $\text{V}_2\text{O}_5$ NB Thickness | 10-20 | nm | Typical range, determined by ac-STEM side-on views |
| $\text{V}_2\text{O}_5$ NB Mean Length | 134 (Range: 15-221) | nm | Statistical analysis of acicular crystals |
| Crystallization Temperature | 365 | °C | Optimal temperature for amorphous to $\alpha-\text{V}_2\text{O}_5$ transition |
| Maximum Specific Capacity | 440 | $\text{mAh g}^{-1}$ | First discharge cycle (lithiation) |
| Cycling Rate | C/10 | Rate | Galvanostatic testing condition |
| Cycling Voltage Window | +3.6 to +1.5 | V vs. $\text{Li} | \text{Li}^{+}$ |
| $\alpha-\text{V}_2\text{O}_5$ Lattice Parameter (a) | 11.519 | Å | Orthorhombic structure |
| $\omega-\text{Li}_3\text{V}_2\text{O}_5$ Lattice Parameter | 4.095 | Å | Rock-salt phase after lithiation |
Key Methodologies
Section titled “Key Methodologies”The successful synthesis and characterization relied on precise control over the BDD substrate and electrochemical parameters:
- BDD Electrode Preparation: High-grade MPCVD BDD material (80 µm or 200 µm thick) was mechanically polished to $\sim \text{nm}$ surface roughness. A Ti/Au ohmic contact was applied to ensure reliable electrical connection.
- Solvent System Optimization: A mixed solvent system (Water:DMF 3:1) was used to leverage the catalytic inertness of BDD, kinetically retarding water oxidation and enabling the deposition of $\text{V}_2\text{O}_5$.
- Electrochemical Synthesis: $\text{V}_2\text{O}_5$ NBs were deposited using a five-step potential pulse (chronoamperometry) methodology, modulating between +1.00 V and +2.00 V vs. SCE to stimulate nucleation and lateral growth.
- Thermal Annealing: The as-deposited amorphous $\text{V}_2\text{O}_5$ was crystallized by annealing in air at $350^\circ\text{C}$ for 2 hours, followed by a 12-hour cool-down.
- Electrochemical Cycling: Galvanostatic cycling was performed in a three-electrode cell using a non-aqueous electrolyte (1 M $\text{LiCl} + 1 \text{M } \text{LiClO}_4$ in Water:MeCN 1:3) at a slow C/10 rate to study phase transitions.
- Atomic-Scale Characterization: Aberration-corrected Scanning TEM (ac-STEM) and Electron Energy-Loss Spectroscopy (EELS) were performed on BDD TEM substrates to visualize the $\alpha \leftrightarrow \omega$ phase transition and local changes in vanadium valence state.
6CCVD Solutions & Capabilities
Section titled “6CCVD Solutions & Capabilities”6CCVD is uniquely positioned to supply the advanced MPCVD diamond materials and fabrication services necessary to replicate and scale this research into viable battery technology.
| Research Requirement (Paper) | 6CCVD Solution & Capability | Technical Advantage |
|---|---|---|
| BDD Electrode Material | Heavy Boron-Doped Diamond (BDD) Wafers/Plates. | We provide BDD with doping levels up to $10^{21}$ B atoms/$\text{cm}^{3}$, guaranteeing the high conductivity and electrochemical stability required to suppress parasitic reactions (like water oxidation) in hybrid electrolytes. |
| Custom Dimensions & Geometry | Custom Laser Cutting and Fabrication Services. | We can supply BDD plates up to 125 mm (PCD) or custom-cut SCD/BDD pieces, perfectly matching the 5 x 10 mm electrodes and 3 mm TEM disks used in this study. |
| Substrate Thickness Control | Precision Thickness Control (0.1 µm to 10 mm). | We offer BDD substrates at the required 80 µm (for TEM) and 200 µm (for bulk electrochemistry), ensuring optimal thermal and electrical properties for in situ experiments. |
| Ohmic Contact Integration | In-House Metalization Services (Au, Pt, Ti, Pd, W, Cu). | We provide the exact Ti/Au ohmic contacts described in the paper, or custom multi-layer stacks, ensuring low-resistance electrical contact critical for accurate galvanostatic cycling and high-current applications. |
| Surface Finish | Ultra-Low Roughness Polishing. | Our polishing achieves Ra < 5 nm for inch-size PCD/BDD, ensuring the smooth, clean surface finish necessary for uniform nucleation and adhesion of the $\text{V}_2\text{O}_5$ nanobelts. |
| Scale-Up Potential | Large-Area PCD/BDD Wafers. | For scaling up cathode material synthesis, we offer Polycrystalline Diamond (PCD) plates up to 125 mm in diameter, providing a robust, conductive platform for industrial-scale electrodeposition. |
Engineering Support
Section titled “Engineering Support”6CCVD’s in-house PhD team specializes in the electrochemical properties of diamond. We offer expert consultation on material selection, doping optimization, and surface preparation for projects involving hybrid aqueous/nonaqueous batteries and advanced electrodeposition synthesis methodologies.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Electrodeposition is used to produce α-V 2 O 5 nanobelts on a boron doped diamond electrode. The nanoscale dimensions facilitate accommodation of three Li + ions during discharge resulting in ω-Li 3 V 2 O 5 , which is reversible over at least one cycle.