(491e) a General and Mild Approach to Controllable Preparation of Manganese-Based Micro/Nanostructured Bars for High Performance Lithium-Ion Batteries

To meet the requirements for large-scale applications in electric vehicles, hybrid electric vehicles and stationary energy storage, growing interest has been directed at the economical, sustainable and environmental friendly methods to produce electrode materials for rechargeable lithium ion batteries (LIBs) with high energy and power densities.

Recently, manganese-based electrode materials, such as layered LiNixCo1-x-yMnyO2, spinel LiNi0.5Mn1.5O4 and layered Li-rich xLi2MnO3â?¢(1-x)LiNi1/3Mn1/3Co1/3O2 (0 â?¤ x â?¤ 1) have received a flurry of research activities due to their advantages of high energy and power densities, low cost and high cycling performance.

In respect to thermal stability, larger particles with a higher tap-density would be less reactive in a highly oxidized state. On the other hand, an electrode consisting of uniform particles with an appropriate size could ensure a homogeneous intercalation reversibility from particle to particle over repeated cycles. Therefore, the control of particle size and morphology for tailoring lithium-ion battery electrode materials has been paid more and more attention in recent years. Till now, it has remained a challenge to develop a general strategy that allows the large-scale preparation of a wide array of 1D micro/nanostructured manganese-based electrode materials with a controllable phase, composition and shape, as well as a narrow size distribution.

Herein we have established a Chimie Douce approach --- by mixed solvent co-precipitation --- to selectively prepare an extensive series of 1D micro/nanostructured manganese-based electrode materials, both cathode and anode for LIBs with high energy and power densities, attesting to its generality and effectiveness. Based on the kinetic elaboration of crystallite nucleation and growth through mixed solvent mediation, the new route is easily controllable, repeatable, and generalizable to the fabrication of a large series of some highly promising manganese-based electrode materials with tunable 1D micro/nanostructures for enhanced performances in lithium ion batteries. As a significant difference from the conventional methods, the present method is conducted in ethanol/water mixed solutions at room temperature, without having recourse to long-chain surfactants or hydrothermal condition. In addition, it can be employed to produce different aspect ratios of microbars with mixed transition metal oxides by tuning the ethanol/water volume ratio in the mixed solvent. It is anticipated that the mixed solvent mediated co-precipitation strategy will open opportunities to heuristically and systematically design mixed transition metal oxides with controllable phase and composition, including not only manganese-based but also other metal-based materials, with desirable micro-/nano-structures for developing high performance lithium-ion batteries.