3D-Printing Water-Soluble Channels Filled with Liquid Metal for Recyclable and Cuttable Wireless Power Sheet

TL;DR

This paper introduces a recyclable, cuttable wireless power sheet using water-soluble channels filled with liquid metal, maintaining functionality after damage and enabling recovery and reuse of materials.

Contribution

It presents a novel 3D-printed water-soluble channel design filled with liquid metal for recyclable and durable wireless power transfer sheets.

Findings

Achieved a Q-factor over 55 at 6.78 MHz.

Maintained electrical resistance and bending stiffness after 100 cycles.

Recovered 98% of liquid metal after four dissolution-refabrication cycles.

Abstract

A recyclable and cuttable wireless power transfer (WPT) sheet is proposed, enabled by H-tree wiring and water-soluble channels filled with liquid metal (LM). Conventional 2D WPT systems lose their functionality when physically damaged or modified. The H-tree wiring pattern maintains the operation of the remaining coils even after the outer region of the sheet is cut away. The LM can be recovered by dissolving 3D-printed polyvinyl alcohol (PVA) channels in water. The sheet dimensions were experimentally optimized, and a Q-factor over 55 was achieved at 6.78 MHz. The sheet maintained its bending stiffness and electrical resistance during 100 bending cycles. After four dissolution-refabrication cycles, 98 percent of the LM was recovered with stable electrical properties. The WPT sheet can be integrated into everyday objects and enables long-term, continuous operation of surrounding electronic devices, contributing to IoT applications and ambient computing.