Shape-controlled synthesis of hierarchically layered lithium transition-metal oxide cathode materials by shear exfoliation in continuous stirred-tank reactors

Abstract

Developing hierarchically layered cathode materials with high performance is key to further improving advanced lithium-ion batteries, but it is challenging to synthesize such systems with controllable shape on a large scale. We used a high-shear mixer to continuously prepare flower-like hydroxide precursors via a co-precipitation method in a continuous stirred-tank reactor (CSTR). After the lithiation reaction, hierarchical lithium transition-metal oxides with predominantly exposed electrochemically active {010} planes are produced. The electrochemical properties of these peculiar materials (i.e. LiNi_1/3Co_1/3Mn_1/3O₂, LiNi_0.6Co_0.2Mn_0.2O₂ and Li_1.2Ni_0.2Mn_0.6O₂) are demonstrated to be excellent. Particularly, LiNi_1/3Co_1/3Mn_1/3O₂ exhibits a durable high-rate capability with a capacity retention of 98.2% after 500 cycles at 20C between 2.7 and 4.3 V. This work provides a new technology to fabricate two-dimensional nanoarchitectured electrode materials. Moreover, the outstanding electrochemical properties of this hierarchically structured cathode material in combination with the scalable method make it highly interesting for commercialization.