Ultra-Durable Polysilicon Based Tribovoltaic Nanogenerators for Bearing In Situ Rotational Speed Sensing

Area of Science:

• Materials Science
• Energy Harvesting
• Mechanical Engineering

Background:

• Tribovoltaic nanogenerators (TVNGs) offer high power density but often rely on expensive, fragile single-crystal materials.
• Existing TVNGs face limitations in cost and structural robustness for widespread industrial applications.

Purpose of the Study:

• To develop a cost-effective and robust polysilicon-based TVNG for in situ rotational speed sensing in bearings.
• To investigate the performance and durability of polysilicon TVNGs in different operational modes.
• To demonstrate the feasibility of integrating TVNGs into various bearing types for intelligent sensing.

Main Methods:

• Fabrication of polysilicon-based TVNGs utilizing defects for carrier generation and managing grain boundary effects.
• Testing of TVNGs in oiled sliding and rolling modes to evaluate durability and friction coefficients.
• Manufacturing of tapered roller, thrust ball, and deep groove ball bearings incorporating rolling mode polysilicon TVNGs.
• Characterization of the linear relationship between electrical output (short-circuit current and open-circuit voltage) and rotational speed.

Main Results:

• Polysilicon TVNGs achieve performance comparable to single-crystal devices at a lower cost.
• Oiled sliding mode TVNGs demonstrate exceptional durability up to 1 million cycles.
• Rolling mode TVNGs exhibit a low friction coefficient (0.14) and a high fitting coefficient (0.99) for speed sensing.
• The short-circuit current and open-circuit voltage show a strong linear correlation with rotational speed.

Conclusions:

• Polysilicon TVNGs present a viable, economical alternative for energy harvesting and sensing applications.
• The developed structure-function integrated bearing design enables in situ rotational speed sensing.
• This technology holds significant potential for intelligent components in the Industrial Internet of Things (IIoT).