Confined growth of primary grains towards stabilizing integrated structure of Ni-rich materials

Abstract

Controllable microstructure growth is desirable for materials to achieve optimized performance. Herein, we demonstrate that LiNi0·8Co0·15Al0·05O2, a promising cathode for lithium ion batteries toward high energy density, can be crystallized in a Mn-rich confined environment, leading to the regulation of the size of primary grains. As a result, the material with the Mn-content of 3 wt% exhibits a substantial enhancement in capacity retention of 81% after 900 cycles at 2 C between 2.8 and 4.3 V, relative to the corresponding value of 55% for the pristine counterpart. The exceptional performance is further highlighted by the full cell with the Mn-doped LiNi0·8Co0·15Al0·05O2 cathode and Li4Ti5O12 as the anode, exhibiting capacity retention of 86% after 1000 cycles. This mainly means that the reduction of the size of the primary grains in the integrated structure can alleviate the intrinsic internal strain induced by delithiation/lithiation of the material and consequently diminish the formation of microcracks in the nickel-rich materials.