Shear-structured MoNb6O18 as a new anode for lithium-ion batteries

Abstract

Owing to their high theoretical capacities, safe operational voltage, unique tunnel-shaped structural features for fast lithium ion transfer, and structural stability, niobium-based oxides are regarded as promising candidate anode materials for lithium-ion batteries (LIBs). Here, molybdenum niobium oxide (MoNb₆O₁₈) with a high theoretical capacity of 399 mA h g⁻¹ (Mo⁶⁺/Mo⁴⁺ and Nb⁵⁺/Nb³⁺) was developed as a new anode material for LIBs. The crystal structure of MoNb₆O₁₈ was observed to display a Wadsley–Roth phase of the ReO₃ shear structure. The discharge capacity of micron-sized particles of MoNb₆O₁₈ was measured to be 219.4 mA h g⁻¹ with a high initial Coulombic efficiency of 96.8% at 0.2C and 154.3 mA h g⁻¹ at 1C from 1.0 to 3.0 V. The results of ex situ X-ray diffraction (XRD) experiments revealed the ability of MoNb₆O₁₈ to serve as an intercalation-type anode material for lithium ion storage with outstanding structural stability. Also, an LiMn₂O₄//MoNb₆O₁₈ full cell displayed desirable lithium-ion storage properties.