Low‐temperature induced crystallographic orientation boosting Li storage performance of Na 2 MoO 4 ·2H 2 O

Abstract The design and development of high‐performance anodes pose significant challenges in the construction of next‐generation rechargeable lithium‐ion batteries (LIBs). Sodium molybdate dihydrate (Na 2 MoO 4 ·2H 2 O) has garnered increasing attention due to its cost‐effectiveness, non‐toxicity and earth abundance. To enhance the Li storage performance of Na 2 MoO 4 ·2H 2 O, a crystallographic orientation regulation strategy is proposed in this work. Initially, density functional theory calculations are carried out to demonstrate that the (020) crystal plane of Na 2 MoO 4 ·2H 2 O offers the lowest energy barrier for Li + migration. Subsequently, the preferred crystallographic orientation of Na 2 MoO 4 ·2H 2 O crystal is tuned through a low‐temperature recrystallization method. Furthermore, the microstructure and phase changes of Na 2 MoO 4 ·2H 2 O during the lithiation/de‐lithiation process are studied using in situ and ex situ XRD tests, ex situ XPS and cyclic voltammetry to unravel its Li + storage mechanism. Upon application as LIBs anode, the Na 2 MoO 4 ·2H 2 O single‐crystal particles with a preferred (020) surface exhibit superior reversible capacity, high‐capacity retention and high cycling stability. The enhanced Li storage performance should be attributed to the regulated crystallographic orientation and small changes in the crystal microstructure during the charge/discharge process, which facilitates Li + migration and bolsters structural stability. Notably, this study introduces a novel concept and a simple synthesis method for the advancement of electrodes in rechargeable batteries.