High-Rate Structure-Gradient Ni-Rich Cathode Material for Lithium-Ion Batteries.

To simultaneously achieve high compaction density and superior rate performance, a structure-gradient LiNi0.8Co0.1Mn0.1O2 cathode material composed by a compacted core and an active-plane-exposing shell was designed and synthesized via a secondary co-precipitation method successfully. The tight stacking of primary particles in the core part ensures high compaction density of the material, whereas the exposed active planes, resulting from the stacking of primary nanosheets along the [001] crystal axis predominantly, in the shell region afford enhanced Li+ transport. Thus, this structure-gradient Ni-rich cathode material shows a high compaction density with excellent electrochemical performances, especially the rate performance, exhibiting excellent rate capability (160 mA h g-1 at 10 C), which is 62% larger than that of the pristine material within 2.75-4.3 V (vs Li+/Li). Our work proposes a possible strategy for designing and synthesizing layered cathode materials with the required hierarchical structure to meet different application requirements.