Preparation and Rate Capability of Carbon Coated LiNi_1/3Co_1/3Mn_1/3O₂as Cathode Material in Lithium Ion Batteries

Abstract

LiNiCoMnO (NCM) is regarded as a promising material for next-generation lithium ion batteries due to the high capacity, but its practical applications are limited by the poor electronic conductivity. Here, a one-step method is used to prepare carbon coated LiNiCoMnO (NCM/C) by applying active carbon as reaction matrix. TEM shows LiNiCoMnO particles are homogeneously coated by carbon with a thickness about 10 nm. NCM/C delivers the discharge capacity of 191.2 mAh g at 0.5 C (85 mA g) with a columbic efficiency of 91.1%. At 40 C (6800 mA g), the discharge capacity of NCM/C is 54.6 mAh g, whereas NCM prepared through sol-gel route only delivers 13.2 mAh g. After 100 charge and discharge cycles at 1 C (170 mA g) the capacity retention is 90.3% for NCM/C, whereas it is only 72.4% for NCM. The superior charge/discharge performance of NCM/C owes much to the carbon coating layer, which is not only helpful to increase the electronic conductivity but also contributive to inhibit the side reactions between LiNiCoMnO and the liquid electrolyte.

Mechanochemical Synthesis of γ‐Graphyne with Enhanced Lithium Storage Performance

“…The relationship of Z ′ (the real part impedance) and ω −1/2 (ω is the angular frequency, ω = 2 πf ) in the low‐frequency region is further discussed and displayed in Figure d. The Warburg impedance coefficient (σ) and the Li + diffusion coefficient ( D Li+ ) are calculated according to Equations and . The Li + diffusion coefficient ( D Li+ ) of γ‐graphyne is estimated to be 9.63 × 10 −9 cm 2 s −1 , which is higher than that of other carbon materials (1 × 10 −9 to 1 × 10 −12 cm 2 s −1 ) like graphite or carbon fiber .…”

Enhanced High Voltage Performance of Chlorine/Bromine Co-Doped Lithium Nickel Manganese Cobalt Oxide

“…The redox process at 2.5~4.4 V corresponds to the Ni 2+ /Ni 4+ couple, and that at 4.4~4.6 V corresponds to the Co 3+ /Co 4+ couple. Much attention has been given to the improvements of its structural stability and electrochemical behavior below 4.5 V [5][6][7][8][9]. In our previous work, LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathode materials were synthesized by the molten salt method, and the electrochemical performance between 2.8-4.4 V was investigated [10,11].…”

In Situ Chelating Synthesis of Hierarchical LiNi1/3Co1/3Mn1/3O2 Polyhedron Assemblies with Ultralong Cycle Life for Li‐Ion Batteries

“…Previous reports showed that the structure/morphology of LiNi 1/3 Co 1/3 Mn 1/3 O 2 plays an important role of electrochemical performances . For example, surfaces with high exposure ratio of {010} facets are beneficial for the improvement in rate capability . Mesoporous structure minimizes solid‐state diffusion paths and facilitates mass transport of ions and electrolytes to electrochemically active sites .…”

“…As shown in Figure c, the particles with sharp edges fuse together, and Figure d shows the lattice‐resolved high‐resolution TEM (HRTEM) image corresponding to the edge in Figure c, displaying lattice fringes of the planes with spacing of 0.476 and 0.247 nm, matching well with the lattice space of (003) and (010) facets of LiNi 1/3 Co 1/3 Mn 1/3 O 2 , respectively, and the fast Fourier transform (FFT) pattern also certifies the existence of these two crystal facets (Figure e). The exposed electrochemically active crystal facets of {010} can provide more channels for Li + migration . The energy dispersive X‐ray spectroscopy (EDX) mappings reveal that all the elements are uniformly distributed (Figure g,f).…”