The tube transducer as a novel source for power ultrasound: A case study in delamination of graphite coating from lithium-ion battery anode

TL;DR

This study introduces a novel tube transducer for ultrasonic applications, demonstrating its ability to generate high-intensity cavitation throughout its bore, suitable for large-scale sonochemical processes like battery material recycling.

Contribution

The paper presents the design and characterization of a new tube transducer that produces distributed high-intensity cavitation, offering a scalable alternative to conventional sonotrodes for industrial sonochemistry.

Findings

Tube transducer generates cavitation comparable to or higher than sonotrodes.

Cavitation is distributed throughout the tube's bore, not just at the tip.

Effective in delaminating graphite coating from lithium-ion battery anodes.

Abstract

Developing high throughput applications of sonochemistry and sonoprocessing is an outstanding ultrasonic engineering challenge that continues to limit widespread industrial adoption. Conventional mass-produced Langevin-based technologies, such as the sonotrode or cleaning bath transducers, are not particularly well suited to treating large liquid volumes or flow-based systems, with a compromise between cavitation intensity and distribution through liquid bulk typically required. We report on the development of a tube transducer from a single element radially poled tubular piezoceramic, excited to generate an axially focused field. High-speed imaging and sonochemiluminescence are used to characterise the cavitation generated, which is also compared to the well-known activity at the tip of a sonotrode. Tube transducer and sonotrode sonications are then assessed for the material recycling application of graphite coating delamination from lithium-ion battery anode, both for intact and flaked anode sheets. The findings show that the tube transducer generates cavitation at sonotrode-like intensities or higher but distributed throughout the bore of the tube, with peak activity at the central axis. Prospects for developing tube transducer technology for high throughput flow-based applications are discussed.