Electrodeposited Ni–Fe Alloy Foils with Changeable Nanostructures and Magnetic Properties for High Performance Wireless Charging

Ni–Fe alloy foils for wireless charging have been prepared by electrodeposition from a sulfate plating solution at different bath temperatures. Systematic investigations have been conducted on the structure and composition of Ni–Fe alloy foils. The dependence of magnetic properties on bath temperatures has also been explored. The results show that with the bath temperature increasing, the (200) texture intensity, Ni mass fraction, and grain size of the Ni–Fe alloy foils gradually increase. In addition, Ni–Fe foils prepared at 70 °C have lowest coercivity, highest real part of the complex permeabilities (μ′) and large μ′Q (Q = μ'/μ"). Meanwhile, the application of Ni–Fe alloy foils for wireless charging has been investigated. It is found that adding a Ni–Fe alloy foils would effectively enhance coupling coefficient (k) for wireless charging, which benefits from the alloy’s higher μ′ and smaller coercivity. When the bath temperature is 70 °C, k value can reach 0.64, which is comparable to conventional ferrite products. This work not only reveals the effect of bath temperature on the composition, structure, and magnetic properties of Ni–Fe alloy foils, but also offers novel insights into the application of Ni–Fe alloys foils for wireless charging.