High-entropy-doping effect in a rapid-charging NbO lithium-ion battery negative electrode.

Doping is an important approach to tailor materials' properties, yet the success of doping can depend on factors such as ionic radii similarities. For materials like silicon or perovskite, doping is not only facile to implement but can also enhance material properties. However, for host lattice structures like NbO, doping without causing phase change is challenging. Here, we introduce a high-entropy-doping effect in NbO. Unlike traditional doping approaches, high-entropy-doping minimizes the chemical properties of doping elements and focuses solely on their quantities. By high-entropizing the doping elements (selecting 10-15 from Mg, Ca, Sr, Ba, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Ga, In, Sn, Sb, Y, Mo, La, Ce) and keeping them within a certain range of doping concentrations (1-3 %), a successful high-entropy-doping is achieved for NbO without phase change. The obtained high-entropy-doped (HED) NbO exhibits rapid-charging capabilities. At a rate of 40 A g, the HED-NbO delivers a capacity of 80 mAh g, whereas the undoped NbO fails to exceed 25 mAh g.