Hierarchical porous LiNi_1/3 Co_1/3 Mn_1/3 O₂ Nano-/Micro spherical cathode material: Minimized cation mixing and improved li + mobility for enhanced electrochemical performance

Although being considered as one of the most promising cathode materials for Lithium-ion batteries (LIBs), LiNi_1/3 Co_1/3 Mn_1/3 O₂ (NCM) is currently limited by its poor rate performance and cycle stability resulting from the thermodynamically favorable Li⁺/Ni²⁺ cation mixing which depresses the Li + mobility. In this study, we developed a two-step method using fluffy MnO₂ as template to prepare hierarchical porous nano-/microsphere NCM (PNM-NCM). Specifically, PNM-NCM microspheres achieves a high reversible specific capacity of 207.7 mAh g -1 at 0.1 C with excellent rate capability (163.6 and 148.9 mAh g -1 at 1 C and 2 C), and the reversible capacity retention can be well-maintained as high as 90.3% after 50 cycles. This excellent electrochemical performance is attributed to unique hierarchical porous nano-/microsphere structure which can increase the contact area with electrolyte, shorten Li + diffusion path and thus improve the Li + mobility. Moreover, as revealed by XRD Rietveld refinement analysis, a negligible cation mixing (1.9%) and high crystallinity with a well-formed layered structure also contribute to the enhanced C-rates performance and cycle stability. On the basis of our study, an effective strategy can be established to reveal the fundamental relationship between the structure/chemistry of these materials and their properties.