Superlubric Schottky Generator in Microscale with High Current Density and Ultralong Life

TL;DR

This paper introduces a microscale superlubric Schottky generator that achieves high current density and long-lasting operation by utilizing ultralow friction contact, supporting the depletion layer mechanism and promising applications in energy harvesting.

Contribution

The study presents the first experimental demonstration of a superlubric Schottky generator with high current density and durability, validating the depletion layer mechanism through simulation.

Findings

High current density (~119 A/m^2) sustained over 5,000 cycles.

No observable wear or current decay during operation.

Experimental support for the depletion layer establishment and destruction (DLED) mechanism.

Abstract

Miniaturized or even microscale generators that could effectively and persistently converse weak and random mechanical energy from environments into electricity promise huge applications in the internet of things, sensor networks, big data, personal health systems, artificial intelligence, etc. However, such generators haven't appeared yet because either the current density, or persistence, or both of all reported attempts were too low to real applications. Here, we demonstrate a superlubric Schottky generator (SLSG) in microscale such that the sliding contact between a microsized graphite flake and an n-type silicon is in a structural superlubric state, namely a ultralow friction and wearless state. This SLSG generates a stable electrical current at a high density (~119 Am-2) for at least 5,000 cycles. Since no current decay and wear were observed during the entire experiment, we believe that the real persistence of the SLSG should be enduring or substantively unlimited. In addition, the observed results exclude the mechanism of friction excitation in our Schottky generator, and provide the first experimental support of the conjectured mechanism of depletion layer establishment and destruction (DLED). Furthermore, we demonstrate a physical process of the DLED mechanism by the use of a quasi-static semiconductor finite element simulation. Our work may guide and accelerate future SLSGs into real applications.