Hierarchical Porous LiNi1/3Co1/3Mn1/3O2 Nano-/Micro Spherical Cathode Material: Minimized Cation Mixing and Improved Li+ Mobility for Enhanced Electrochemical Performance

Abstract

Although being considered as one of the most promising cathode materials for Lithium-ion batteries (LIBs), LiNi1/3Co1/3Mn1/3O2 (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.

Enhanced Electrochemical Properties of Zr4+-doped Li1.20[Mn0.52Ni0.20Co0.08]O2 Cathode Material for Lithium-ion Battery at Elevated Temperature

“…The as-prepared samples have mainly demonstrated the typical XRD patterns of the hexagonal α-NaFeO 2 structure with the space group R-3m (the LiMO 2 features), except for the weak super lattice peaks between 20° and 25°, which are related to the Li 2 MnO 3 phase, corresponding to the monocline unit cell C2/m 19,20 . In addition, the distinct splitting of (006)/(102) and (018)/(110) peaks have indicated that the as-prepared cathode materials have formed a well-developed hexagonal layered structure 21 . Besides, to further investigate the cation mixing between the Ni 2+ and Li + in the LiMO 2 main phase, the Rietveld refinement of the diffraction patterns was performed based on the R-3m (used for LiNi 0.50 Co 0.20 Mn 0.30 O 2 phase) and C2/m (used for Li 2 MnO 3 phase) structure, as is shown in Fig.…”

Printed Graphene Electrochemical Biosensors Fabricated by Inkjet Maskless Lithography for Rapid and Sensitive Detection of Organophosphates

“…The linearity demonstrates that the process is diffusion-controlled; however, the faradaic peaks shift further aparta characteristic that is commonly attributed to porous materials that experience slower target analyte diffusion rates. 53 Using the Randles−Sevcik equation (eq 1 & Supporting Information Figure S6), the electrochemically active surface area was estimated as 5, 53, and 56 mm 2 for SPCE, laserannealed IML-PGE, and laser-annealed PtNP-IML-PGE, respectively.…”

Facile synthesis of self-standing binder-free vanadium pentoxide-carbon nanofiber composites for high-performance supercapacitors

“…In the Figure 8, it can be seen that the slope of the Warburg tail is higher for the VOCF-5 compared that of VOCF-7. This result indicates the higher mobility of electrolyte ions toward V2O5 surface in the VOCF-5 compared to VOCF-7 [47].…”