Application of Boron-Doped Single-Crystal Diamond in Supercapacitors

Supercapacitors store energy through either the electric double layer formed at the electrode/electrolyte interface or redox reactions occurring at the interface, functioning as energy storage devices that bridge the gap between traditional capacitors and rechargeable batteries. As an electrode material for supercapacitors, boron-doped diamond films offer advantages such as a wide potential window, high electrochemical stability, and environmental friendliness (no pollution). However, due to the low background current of boron-doped diamond, the amount of stored charge is relatively small. Currently, most research focuses on increasing the specific surface area of boron-doped diamond electrodes to enhance the contact sites between the electrode and electrolyte, thereby improving the specific capacitance of BDD electrodes.

Boron-doped diamond films were grown on TiO₂ nanotubes via microwave plasma chemical vapor deposition (MPCVD), forming a unique columnar BDD morphology with intergranular defects. This structure increases the electrode’s specific surface area, achieving a specific capacitance of 7.46 mF·cm⁻². Additionally, laser-induced periodic surface structuring (LIPSS) technology was used to create a nanostructured surface on boron-doped diamond electrodes, significantly enhancing their electrochemical performance. Porous boron-doped diamond films were also prepared using the self-assembled seeding method combined with MPCVD, reaching a specific capacitance of 17.18 mF·cm⁻². Multilayer film electrodes fabricated based on this approach exhibited an even higher specific capacitance of 25.48 mF·cm⁻², with a capacitance retention rate of over 90% after 10,000 cycles. This method is simple, highly reproducible, and eliminates the need for templates, binders, or etching processes, holding potential implications for numerous future applications in energy storage devices.

Currently, supercapacitors are gaining traction in various fields: they serve as main power sources for equipment such as power tools, toys, and small tractors; backup power sources for motherboards of large electronic devices; and when combined with lithium-ion capacitors or batteries, they can act as energy storage systems for new energy electric vehicles or hybrid electric vehicles. Compared with other carbon materials, boron-doped diamond features a wider potential window and stronger electrochemical stability. As solutions to challenges like high costs and complex fabrication processes are developed, it is expected to find widespread application in this field.

The boron-doped single-crystal diamond produced by CSMH can achieve doping from low concentration to high concentration. It has realized a uniform and controllable concentration and a customizable boron doping process.CSMH uses the MPCVD method to prepare large-sized and high-quality diamonds,and currently has mature products such as diamond heat sinks, diamond wafers, diamond windows,diamond hetero junction integrated composite substrates,etc.