Zentek Files Patent for Graphite-Based EMI Shielding Coating

Zentek Ltd. (TSXV: ZEN) (NASDAQ: ZTEK) has filed a provisional patent application with the U.S. Patent and Trademark Office covering ZEN-EMI-01, a water-based EMI shielding coating made from purified graphite sourced from the company's Albany deposit in Northern Ontario. The filing establishes a priority date and marks the first formal step in protecting Zentek's EMI shielding coating platform.

Most EMI shielding today relies on reflection — metal or metal-filled materials that bounce electromagnetic energy away from a component. That approach works, but in densely packed electronic systems, the reflected energy has to go somewhere, and it can end up interfering with neighboring devices. ZEN-EMI-01 takes a different approach: rather than reflecting incoming EM energy, it absorbs it and converts it into a small amount of heat inside the coating itself.

The coating combines three materials — purified graphite from the Albany deposit for electrical conductivity, magnetic ferrite particles for magnetic absorption, and a conductive polymer that binds the system together. Because it's water-based, Zentek says the coating can be applied with standard industrial spray, brush, or roll equipment rather than specialized processing.

In internal lab testing at Zentek's Guelph, Ontario facility, a coating layer roughly the thickness of two sheets of paper significantly reduced X-band microwave frequencies (8–12 GHz) commonly used in radar and satellite communications, with reflected signal levels measured below 5 dB across the tested range — indicating that absorption, not reflection, accounted for most of the shielding effect. These are preliminary, internally generated results that have not yet been independently verified; third-party testing against recognized standards and benchmarking against commercial shielding products are part of the company's ongoing development plan.

Zentek positions the technology as particularly relevant to applications where electronics are dense, weight is constrained, and interference is difficult to manage — including telecommunications infrastructure, automotive radar, aerospace, and defense electronics. The company notes that ZEN-EMI-01 has not been tested or qualified for any specific application, and it currently has no customer agreements in these sectors.

"Shielding a modern electronic platform is a weight and geometry problem, and the conventional answer is still metal," said Moe Jiwan, CEO of Zentek. He described ZEN-EMI-01 as a coating that can be applied to shapes and surfaces difficult to shield with metal, built from graphite the company already owns through its Albany deposit.

Dr. Seyyedarash Haddadi, Senior Materials Scientist at Zentek, said the coating's performance comes from how its three components are engineered together — the exfoliated graphite forming the conductive network, the polymer creating the interface, and the ferrite phase contributing magnetic loss — while remaining compatible with conventional coating manufacturing methods.

The provisional filing opens a 12-month window during which Zentek may pursue international and national patent applications claiming priority to it. Over that period, the company's development plan includes third-party verified shielding effectiveness testing, formulation optimization, durability and substrate testing with prospective defense, aerospace, and communications partners, and process scale-up. The technology remains at laboratory stage, and there is no assurance the program will result in a commercial product or that patent protection will be granted.