CoNiO2/Co3O4 Nanosheets on Boron Doped Diamond for Supercapacitor Electrodes

At a Glance

Metadata	Details
Publication Date	2024-03-05
Journal	Nanomaterials
Authors	Zheng Cui, Tianyi Wang, Ziyi Geng, Linfeng Wan, Yaofeng Liu
Institutions	State Key Laboratory of Superhard Materials, Chengdu Normal University
Citations	6
Analysis	Full AI Review Included

Technical Analysis: CoNiO₂/Co₃O₄ Nanosheets on Boron Doped Diamond for Supercapacitor Electrodes

This document analyzes the research detailing the synthesis and performance of CoNiO₂/Co₃O₄ nanosheet arrays anchored on Boron Doped Diamond (BDD) films, positioning 6CCVD’s MPCVD diamond capabilities as the ideal solution for replicating and advancing this high-performance supercapacitor technology.

Executive Summary

Core Achievement: Successful fabrication of high-performance asymmetric supercapacitor electrodes utilizing vertically aligned CoNiO₂/Co₃O₄ nanosheets anchored on a highly conductive MPCVD Boron Doped Diamond (BDD) film.
Performance Metrics: The hybrid electrode achieved a large areal specific capacitance of 214 mF cm⁻² (at 1 mA cm⁻²).
Energy Density Advantage: The BDD substrate provides a wide potential window (up to 1.2 V), which is critical for maximizing energy density (E proportional to V²) in electrochemical storage devices.
Device Performance: The assembled asymmetric supercapacitor (CoNiO₂/Co₃O₄/BDD // Activated Carbon) delivered a maximum energy density of 7.5 W h kg⁻¹ at a power density of 330.5 W kg⁻¹.
Cycling Stability: The device exhibited superior long-term stability, maintaining 97.4% capacitance retention after 10,000 charge/discharge cycles.
Synthesis Method: The BDD films were synthesized using Microwave Plasma Chemical Vapor Deposition (MPCVD), followed by a simple one-step potentiostatic electrodeposition method for the metal oxide nanosheets.

Technical Specifications

The following hard data points were extracted from the synthesis and performance results:

Parameter	Value	Unit	Context
BDD Film Thickness	20	µm	Synthesized via MPCVD
BDD Conductivity	113.63	S cm⁻¹	Measured by Hall effector
MPCVD Microwave Power	2200	W	BDD synthesis condition
MPCVD Substrate Temperature	~850	°C	BDD synthesis condition
Gas Ratio (CH₄/H₂)	5	%	BDD reaction source
Optimum Nanosheet Thickness	20	nm	AFM analysis (2500 s deposition time)
Annealing Temperature	300	°C	Post-electrodeposition treatment in Argon
Electrode Areal Capacitance (Max)	214	mF cm⁻²	CoNiO₂/Co₃O₄/BDD at 1 mA cm⁻²
Operating Voltage Window (Electrode)	1.2	V	CoNiO₂/Co₃O₄/BDD in 1 M Na₂SO₄
Device Energy Density (Max)	7.5	W h kg⁻¹	Asymmetric Supercapacitor (BDD/AC)
Device Power Density (Corresponding)	330.5	W kg⁻¹	Asymmetric Supercapacitor (BDD/AC)
Device Cycling Stability	97.4	% retention	After 10,000 cycles in 6 M KOH

Key Methodologies

The fabrication process relies on two distinct stages: high-quality BDD substrate growth and subsequent metal oxide deposition.

BDD Substrate Synthesis (MPCVD):
- Equipment: Microwave Plasma Chemical Vapor Deposition (MPCVD).
- Substrate Preparation: Silicon wafers were polished using nanodiamond particles (5-10 nm) and ultrasonically treated to maximize nucleation density.
- Growth Parameters: Methane (CH₄) to Hydrogen (H₂) ratio was fixed at 5%. Boron doping was achieved using trimethyl borate (C₃H₉BO₃).
- Result: Production of a dense, crack-free BDD film with a thickness of 20 µm and high conductivity (113.63 S cm⁻¹).
CoNiO₂/Co₃O₄ Nanosheet Fabrication (Electrodeposition):
- Method: One-step potentiostatic electrodeposition using a standard three-electrode system (BDD working electrode, Pt counter electrode, Ag/AgCl reference electrode).
- Electrolyte: Aqueous solution containing Ni(NO₃)₂·6H₂O, Co(NO₃)₂·6H₂O, and NH₄Cl.
- Deposition Voltage: Constant voltage of -1.0 V.
- Optimization: Deposition time was optimized to 2500 s to yield vertically aligned nanosheets with an ultrathin thickness of approximately 20 nm, minimizing ion diffusion length and maximizing contact area.
Post-Treatment:
- Annealing: The hybrid structure was annealed at 300 °C for 2 h in an argon (Ar) atmosphere to form the final CoNiO₂/Co₃O₄ composite structure.

6CCVD Solutions & Capabilities

This research validates the critical role of high-quality, highly conductive Boron-Doped Diamond (BDD) substrates in achieving next-generation electrochemical storage performance. 6CCVD is uniquely positioned to supply the necessary materials and customization required to replicate and scale this technology.

Research Requirement	6CCVD Solution & Capability	Technical Advantage
High-Performance BDD Substrates	Custom Boron-Doped Diamond (BDD) Films. We specialize in MPCVD growth, ensuring precise control over boron concentration (doping level) and resulting conductivity (up to 1000 S cm⁻¹).	Guarantees the wide potential window and low background current necessary for maximizing the energy density (E) of the supercapacitor device.
Thickness and Dimension Control	Custom Dimensions and Thicknesses. We offer BDD films from 0.1 µm up to 500 µm thick, and substrates up to 10 mm thick. Plates/wafers are available up to 125 mm (PCD, scalable to BDD).	Easily match the 20 µm BDD film used in the study, or provide larger, inch-size wafers for industrial prototyping and scale-up.
Surface Preparation & Morphology	Custom Polishing and Surface Texturing. While the paper used a rough surface for nucleation, 6CCVD can provide surfaces ranging from ultra-smooth (Ra < 1 nm) to custom-textured finishes.	Enables researchers to optimize the BDD surface for subsequent electrodeposition, enhancing nanosheet adhesion, structural stability, and electrolyte wettability (a key factor noted in the paper).
Electrode Integration	Internal Metalization Services. We offer in-house deposition of standard current collector materials including Au, Pt, Pd, Ti, W, and Cu.	Eliminates the need for external wiring and simplifies the assembly of three-electrode systems or integrated asymmetric devices, ensuring robust electrical contact.
Engineering Support	In-House PhD Team Consultation. Our experts provide material selection and recipe optimization support for advanced electrochemical projects, specifically focusing on high-energy density supercapacitors and wide-potential window applications.	Accelerate your research timeline by leveraging 6CCVD’s deep expertise in MPCVD diamond growth parameters and interface engineering.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

Developing novel supercapacitor electrodes with high energy density and good cycle stability has aroused great interest. Herein, the vertically aligned CoNiO2/Co3O4 nanosheet arrays anchored on boron doped diamond (BDD) films are designed and fabricated by a simple one-step electrodeposition method. The CoNiO2/Co3O4/BDD electrode possesses a large specific capacitance (214 mF cm−2) and a long-term capacitance retention (85.9% after 10,000 cycles), which is attributed to the unique two-dimensional nanosheet architecture, high conductivity of CoNiO2/Co3O4 and the wide potential window of diamond. Nanosheet materials with an ultrathin thickness can decrease the diffusion length of ions, increase the contact area with electrolyte, as well as improve active material utilization, which leads to an enhanced electrochemical performance. Additionally, CoNiO2/Co3O4/BDD is fabricated as the positive electrode with activated carbon as the negative electrode, this assembled asymmetric supercapacitor exhibits an energy density of 7.5 W h kg−1 at a power density of 330.5 W kg−1 and capacity retention rate of 97.4% after 10,000 cycles in 6 M KOH. This work would provide insights into the design of advanced electrode materials for high-performance supercapacitors.

Tech Support

Original Source

DOI: https://doi.org/10.3390/nano14050474

References

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