Tailoring the Wadsley–Roth crystallographic shear structures for high-power lithium-ion batteries

Abstract

Exploring a universal strategy to increase Li-ion storage capacity and ionic conductivity while maintaining a robust crystal framework is a significant challenge for advancing Wadsley–Roth shear phases as promising anodes for high-power lithium-ion batteries. Here we report a potent cation-engineering driven crystallographic shear structure tailoring strategy, demonstrated through a novel titanium niobium tungsten oxide (TNWO). This is a significant model containing inspiring domains with tetrahedron, tetrahedron-free and large-size blocks in the lattice. Theoretical calculations reveal that the TNWO model, featuring the partial absence of a [WO₄] tetrahedron and intrinsic multiple cation features, not only exhibits enhanced electronic conductivity and alleviated Li⁺ adsorbed structural distortion, but also facilitates both horizontal inter-block type and vertical-tunnel type Li⁺ diffusions, accompanied by sufficient redox reactions. Accordingly, it offers 1.48 Li⁺ per metal atom along with a high Li⁺ diffusion coefficient of 10⁻¹² cm⁻² s⁻¹ and remarkable structural stability, featuring a reversible spatial phase transition. Additionally, through modification of surface anisotropy, dimensional uniformity and electronic conductivity of individual TNWO particles, a composite anode demonstrates ultrahigh rate capability (103.7 mA h g⁻¹ at 15 A g⁻¹) and excellent cycling stability (capacity retention of 80% at 5 A g⁻¹ over 4900 cycles). This work is believed to have opened a new avenue for tailoring shear structures and creating unprecedented phases to transcend the existing Wadsley–Roth niobium-based oxide system for next-generation high-power lithium-ion batteries.