Nickel-doped Li2MoO4 as a high-performance anode material for rechargeable lithium-ion batteries

Abstract

Transition metal oxides are promising anode materials for rechargeable lithium-ion batteries (LIBs) because of their high theoretical specific capacity. Li₂MoO₄ (LMO) has a high specific capacity due to its variable oxidation state and alloying reaction, but the low conductivity and large volume expansion significantly impede its practical applications. To overcome these challenges, here we propose a nickel-doping strategy to prepare Li₂Ni_xMo_1−xO₄ (LNMO) as an anode of LIBs by doping Li₂MoO₄ with Ni²⁺ ions using a sol–gel process. The Ni-doping can not only help minimize the path length for ion and electron transport, thus enhancing electron transmission or conductivity, but also offers a mechanical cushion against volume expansion and contraction amid regular insertion and removal of Li⁺. As a result, the as-developed LNMO anode exhibits a higher reversible charge/discharge specific capacity than LMO, in addition to excellent cycling stability. The Li₂Ni_0.05Mo_0.95O₄ anode exhibits a stable lithium storage capacity of 487.2 mA h g⁻¹, much higher than the 210.9 mA h g⁻¹ for the LMO anode after 100 charge/discharge cycles at a current density of 100 mA g⁻¹. This work offers a facile yet effective approach to creating high-performance Li₂MoO₄ anode materials, thus promoting their real-world application in rechargeable LIBs.