Synthesis and Electrochemical Characterization of a Li-Rich Li1.17Ni0.34Mn0.5O2Cathode Material for Lithium-Ion Cells

Lithium-rich layered oxides (LLOs) are considered as one of the most potential layered cathode materials due to their high discharge specific capacity, low cost, and environmental friendliness. However, the decomposition of electrolytes at high voltages (4.7 V) limits the commercial application of LLOs. Furthermore, to meet the demand for high energy density, lithium nickel cobalt manganese oxides (NCMs) need to improve their working voltage. In limited conditions, all LLOs and NCMs need to be used under the medium− high (4.4−4.6 V) cutoff voltage. Herein, we compare the performance of LLOs and NCMs in the voltage window with a medium−high cutoff voltage. Results show that after 100 cycles at high temperature (45 °C), the capacity retention rate of LLO is 98.68%, while that of NCMs is 78.15−96.93%. Differential scanning calorimetry reveals that the exothermic temperature of LLO is increased by 60−100 °C, and thermal release is reduced by 33−93%. LLOs have obvious advantages under medium−high voltages and a promising application prospect. This work systematically analyzes and compares LLOs and NCMs under medium−high voltage, providing guidance for the industrialization of LLOs.

Section: Test Results and Discussionmentioning

confidence: 69%

Comparative Study of High-Temperature Cycling and Thermal Stability of LLOs and NCMs under Medium–High Voltage

Bai

et al. 2023

“…Figure represents a comparison of the electrochemical performance of the NCMO-950 cathode with our previously reported cobalt-free Li 1.17 Ni 0.34 Mn 0.5 O 2 (NMO) cathode material . The results show that the NMO cathode exhibited an initial discharge capacity (250.34 mAhg –1 ) higher than that of the NCMO material (240.9 mAhg –1 ).…”

Section: Resultsmentioning

confidence: 93%

“…Figure 6 represents a comparison of the electrochemical performance of the NCMO-950 cathode with our previously reported cobalt-free Li 1.17 Ni 0.34 Mn 0.5 O 2 (NMO) cathode material. 46 The results show that the NMO cathode exhibited an initial discharge capacity (250.34 mAhg −1 ) higher than that of the NCMO material (240.9 mAhg −1 ). However, the rate performance studies indicate that the cobalt-containing NCMO material exhibits superior rate performance compared to that of the cobalt-free NMO material.…”

Section: Structural Analysismentioning

confidence: 88%

Lithium-Rich Li_1.17Ni_0.17Co_0.17Mn_0.5O₂ Cathode Material for Lithium-Ion Cells: Effect of Calcination Temperature on Electrochemical Performance

Pillai,

Salini,

John

et al. 2023

Self Cite

High-capacity lithium-rich cathode materials become promising candidates for lithium-ion cells. The crystallinity and structural stability of the cathode materials affect their electrochemical properties. Using a simple carbonate co-precipitation method, we report better electrochemical performance for Li1.17Ni0.17Co0.17Mn0.5O2 (NCMO) cathode material. Herein, we identified 950 °C as the optimum calcination temperature for the NCMO cathode material. The X-ray diffraction and SEM analyses revealed that the material synthesized at a high temperature possesses a well-crystallized layered structure. Electrochemical studies revealed that the cathode material synthesized at 950 °C (NCMO-950) delivered the highest discharge capacity of 240.9 mAhg–1 at C/10 rate. The NCMO-950 material maintained a Coulombic efficiency of ∼100% and capacity retention of 97.9% at the end of 100 cycles at C/10 rate, and the material also exhibited excellent rate performance (delivered a capacity of 142.6 mAhg–1 at 5C). Thus, it can be concluded that calcination temperature significantly impacts the structural stability and electrochemical performance of NCMO.

“…Figure a shows the initial charge/discharge profiles of the LR-0 and LR-S samples at a rate of 0.1 C. All electrodes displayed a sloping region (<4.5 V) and a long plateau (4.5–4.6 V) in the charge profiles, with the former corresponding to the lithium ion extraction from the LiMO 2 component and the latter ascribed to the delithiation of the Li 2 MnO 3 component. ,, We can see that the LR-S sample exhibited a lower charge profile than that of LR-0, and the LR-S electrode showed an extra discharge plateau at around 2.5 V, indicating that the spinel structure is formed in the LR-S sample. Besides, the appropriate spinel phase introduced into the Li-rich materials may effectively enhance the ionic conductivity of Li + and increase the electrochemical reaction active sites, resulting in the LR-S sample giving higher discharge profiles and capacities. , The charge capacities are 376.9 and 386.6 mAh g –1 of the LR-0 and LR-S samples, and the discharge capacities are 273.9 and 318.2 mAh g –1 of the LR-0 and LR-S samples, with related columbic efficiencies of 72.65 and 82.31%.…”

Section: Resultsmentioning

confidence: 95%

Simple and Ingenious Manner To Build Li-Rich Layered Materials with Surface Layered/Spinel Heterostructures and Li Deficiencies

Chen

Xie

et al. 2023

The voltage and capacity attenuation is one of the main bottlenecks limiting the commercialization of Li-rich layered materials, the introduction of a spinel structure and Li deficiencies into materials may mitigate or suppress these shortcoming. The Lirich layered materials with surface layered/spinel heterostructures and Li deficiencies (LR-S) are prepared by a simple and ingenious manner; that is, the 10 wt % precursors are added to uptake the volatilize of Li ions, which produced from the Li-rich material (LR-0) in a high-temperature post-treatment process. The generation of the spinel structure and Li deficiencies in the LR-S sample are confirmed by the inductively coupled plasma mass spectrometry, X-ray diffraction, Raman spectra, and high-resolution transmission electron microscopy characterizations. The LR-S sample displayed excellent electrochemical performances; that is, the capacity retentions is 88.92% at 1 C after 200 cycles, and the voltage drop for each cycle is 1.91 mV, respectively. The reason is mainly attributed to the spinel structure serving as a pillar structure and the Li deficiencies modulating the oxidation products of the oxygen ion in the removal/uptake process.