Controllable Fabrication and Li Storage Kinetics of 1 D Spinel LiMn2O4 Positive Materials for Li-ion Batteries: An Exploration of Critical Diameter

Graphical Progress towards the positive : A facile strategy through manipulating KMnO 4 concentration is introduced to precisely fabricate 1 D LiMn 2 O 4 nanorods with four distinct diameter gradients. The LiMn 2 O 4 nanorod with a critical diameter of approximately 70–80 nm displays the highest discharge capacity and promising cycling performance. The role of 1 D crystal size in effecting interface chemical species and electrochemical performance is elucidated by comparative characterization methods. The morphology and size of nanoelectrode materials determine their properties. Compared to the bulk structure electrodes, 1 D electrode materials for Li-ion batteries have been intensively studied owing to their excellent Li + diffusion kinetics. It is generally accepted that smaller-sized electrode materials lead to better Li storage kinetics. In this study, this is found to not be the case in 1 D LiMn 2 O 4 positive materials. A facile strategy of manipulating the KMnO 4 concentration is introduced to precisely fabricate 1 D LiMn 2 O 4 nanorods with four distinct diameter gradients from 30 to 170 nm. The role of 1 D crystal size in effecting interface chemical species and electrochemical performance is elucidated by comparative characterization methods. X-ray photoelectron spectroscopy (XPS) Ar-ion etching technology shows that the Mn 2+ is electrochemically inactive on the surface of the sample, which explains the adverse effects observed on LiMn 2 O 4 nanorods with the minimum diameter of 30–40 nm, such as decreased discharge capacity. The LiMn 2 O 4 nanorod with a critical diameter of approximately 70–80 nm displays the highest discharge capacity and promising cycling performance. This work clarifies an important property that has previously been neglected and deepens the understanding for design of Mn-based positive materials.