O2 Cathode Material Research Articles

Synthesis of Li[Li0.2Mn0.54Ni0.13Co0.13]O2 Cathode Material in Acetate System for Lithium-Ion Battery

Synthesis of Li[Li0.2Mn0.54Ni0.13Co0.13]O2 Cathode Material in Acetate System for Lithium-Ion Battery

Electrochemical Performances of Nickel-Rich Single-Crystal LiNi0.83 Co0.12 Mn0.05 O2 Cathode Material for Lithium-Ion Batteries Synthesized by Tuning Li+ /Ni2+ Mixing.

Single-crystal nickel-rich materials are promising alternatives to polycrystalline cathodes owing to their excellent structure stability and cycle performance while the cathode material usually appears high cation mixing, which may have a negative effect on its electrochemical performance. The study presents the structural evolution of single-crystal LiNi0.83 Co0.12 Mn0.05 O2 in the temperature-composition space using temperature-resolved in situ XRD and the cation mixing is tuned to improve electrochemical performances. The as-synthesized single-crystal sample shows high initial discharge specific capacity (195.5 mAh g-1 at 1 C), and excellent capacity retention (80.1 % after 400 cycles at 1 C), taking account of lower structure disorder (Ni2+ occupying Li sites is 1.56 %) and integrated grains with an average of 2-3 μm. In addition, the single-crystal material also displays a superior rate capability of 159.1 mAh g-1 at the rate of 5 C. This excellent performance is attributed to the rapid Li+ transportation within the crystal structure with fewer Ni2+ cations in Li layer as well as intactly single grains. In sum, the regulation of Li+ /Ni2+ mixing provides a feasible strategy for boosting single-crystal nickel-rich cathode material.

Lithium-ion Migration in Layered Li1.06Ni0.5Co0.2Mn0.3O2 Cathode Materials Synthesized at Different Temperatures

Lithium-ion Migration in Layered Li1.06Ni0.5Co0.2Mn0.3O2 Cathode Materials Synthesized at Different Temperatures

The Electrochemical Performance of LiMn1.96Mg0.04O4 Cathode Material Prepared by Solid-State Combustion Method

The Electrochemical Performance of LiMn1.96Mg0.04O4 Cathode Material Prepared by Solid-State Combustion Method

Preparation and Electrochemical Performance of Modified LiNi0.5Mn1.5O4Cathode Material for Lithium-ion Batteries

Preparation and Electrochemical Performance of Modified LiNi0.5Mn1.5O4Cathode Material for Lithium-ion Batteries

Effect of Heat Treatment Time on Electrochemical Performance of LiMg0.04Mn1.96O4cathode Materials Synthesized by a Solid-State Combustion Method

Effect of Heat Treatment Time on Electrochemical Performance of LiMg0.04Mn1.96O4cathode Materials Synthesized by a Solid-State Combustion Method

The influence of different drying methods on the properties of LiNi0.5Mn1.5O4 material

It was precisely because LiNi[Formula: see text]Mn[Formula: see text]O4 cathode material had many advantages, including high voltage, high power, no pollution, low cost, etc., that it became a research hotspot for lithium-ion cathode materials. Although LiNi[Formula: see text]Mn[Formula: see text]O4 has a three-dimensional Li[Formula: see text] diffusion channel, there are still some problems that lead to capacity decay and reduced cycling stability, limiting its commercial application. In this paper, the LiNi[Formula: see text]Mn[Formula: see text]O4 cathode material was prepared by the freezing precipitation method. We studied the effects of different drying methods, such as blast drying, water bath drying and freeze-drying on the structure, morphology and electrochemical properties of LiNi[Formula: see text]Mn[Formula: see text]O4 cathode materials. The study found that the LiNi[Formula: see text]Mn[Formula: see text]O4 cathode material prepared by the precipitation-freeze-drying method had a complete crystal form, a stable structure and no LixNi[Formula: see text]O impurity peak. The SEM image showed that the particles were smaller and had a smooth surface. The initial discharge-specific capacity at 0.1[Formula: see text]C was 105.2[Formula: see text]mAh⋅g[Formula: see text]. After 50 cycles, its specific discharge capacity was 99.4[Formula: see text]mAh⋅g[Formula: see text] and the capacity retention rate was 94.5%. Compared with LiNi[Formula: see text]Mn[Formula: see text]O4 materials prepared by other methods, it had better electrochemical performance.

Regulation on electrochemical performance of LiNi0.5Mn1.5O4 cathode material via lithium silicate coating with different Li/Si ratio

Surface coating is regarded as an effective means to alleviate the rapid capacity fading of LiNi0.5Mn1.5O4 material. Lithium silicate, as an ideal coating material, combines the advantages of high ionic conductivity, chemical inertness, and HF capture. Considering the influence of Li/Si ratios on Li+ ions diffusion in lithium silicate, the effects of different Li/Si lithium silicate coatings on the structural and electrochemical performance of LiNi0.5Mn1.5O4 material are investigated. The results show that lithium silicate coatings increase the cation disordering degree, improve the crystallinity, stabilize the electrode/electrolyte interface, and improve Li+ diffusion kinetics. Li/Si ratio greatly affects the composition of lithium silicate coating, which changes from Li2Si2O5 + Li2SiO3 (1:1), Li2Si2O5 + Li4SiO4 (2:1, 3:1) to pure Li4SiO4 phase (4:1). First principles calculation manifests that Li+ migration energy barriers decrease with the increase of Li/Si ratio in lithium silicate. At Li/Si = 4:1, the coated sample shows the best electrochemical performance, with specific discharge capacity of 126.7 mAh g−1 at 10 C rate and capacity retention rate of 91.25% after 200 cycles at 1 C rate. The composition of lithium silicate coating can be controlled by changing Li/Si ratio, which in turn regulates the electrochemical performance of LiNi0.5Mn1.5O4 material.

Design of Cu-Substituted O3-Type NaFe0.5 Mn0.5 O2 Cathode Materials for Sodium-Ion Batteries.

O3-type Fe/Mn-based layered oxide cathode materials with abundant reserves have a promising prospect in sodium-ion batteries. However, the electrochemical reversibility of most O3-type Fe/Mn-based oxide cathode materials is still not high enough. Herein, the effect of different Cu contents on the electrochemical properties of O3-NaFe0.50 Mn0.50 O2 materials is systematically investigated. The as-prepared NaFe0.30 Mn0.50 Cu0.20 O2 cathode achieves the synergistic optimization of the interface and bulk phase. It shows superior electrochemical performance, with an initial discharge specific capacity of 114 mAh g-1 at 0.1 C, a capacity retention rate of 94 % after 100 cycles at 0.5 C, and excellent chemical stability in air and water. In addition, the sodium ion full battery based on NaFe0.30 Mn0.50 Cu0.20 O2 cathode and hard carbon anode has a capacity retention rate of 81 % after 100 cycles. This research provides a useful approach for the preparation of low-cost and high-performance O3-type layered cathode materials.

The morphology and electrochemical properties of LiNi0.8Co0.1Mn0.1O2 cathode material prepared by the assistance of CTAB surfactant

The effect of hexadecyl trimethyl ammonium bromide (CTAB), as a surfactant, on morphology and electrochemical properties of LiNi0.8Co0.1Mn0.1O2 cathode materials was systematically investigated. Ni0.8Co0.1Mn0.1(OH)2 precursors were obtained through co-precipitation method using CTAB as a surfactant, then sintered with lithium salt to synthesize LiNi0.8Co0.1Mn0.1O2 cathode materials. XRD and TEM results show that the materials possess rhombohedral α-NaFeO2 layered structure (space group R3¯m), and Ni/Li mixing degrees reduce and the (003) crystal plane spacing enlarges to some degree upon the assistance of CTAB. SEM images prove that the formation of columnar primary particles of can be promoted by the assistance of CTAB. The discharge capacity for the samples reaches the maximum 186.9 mAh∙g−1 at 0.1C while the content of CTAB increases to 0.2%, and NCM 0.2 sample also shows better high-rate charge/discharge ability and preferable cycling performance. Furthermore, NCM 0.2 sample exhibits lower charge transfer impedance and faster diffusion rate of Li+ than that of the blank.

Efficient and scalable encapsulation process of highly conductive 1T-MoS2 nanosheets on Ni-rich LiNi0.83Co0.11Mn0.06O2 cathode materials for high-performance lithium-ion batteries

Ni-rich LiNi1-x-yCoxMnyO2 (NCM) is an attractive cathode material that can meet the growing global demand of the Lithium-ion battery market owing to its high energy density and low cost. However, it still suffers from cyclic and thermal instability due to several issues, such as structural deterioration and excessive cathode electrolyte interface (CEI) layer formation arising from side reactions occurring at the NCM particle surface. In this study, molybdenum disulfide (MoS2) nanosheets with a metallic 1T phase are synthesized by chemical exfoliation, functionalized with polyethyleneimine (PEI), and uniformly coated on the surface of Ni-rich NCM particles through electrostatic interactions. As a result, the ceMoS2-PEI layer effectively alleviates the electrochemical performance degradation of NCM caused by irreversible phase transitions, microcrack formation, transition metal dissolution, and thick CEI layer formation by suppressing side reactions due to direct contact with the organic electrolyte or hydrofluoric acid on the surface of NCM. In addition, the ceMoS2-PEI layer provides a sufficient transport pathway for charge transfer and Li+ ion diffusion, thereby mitigating electrode polarization and impedance increase. Consequently, NCM/ceMoS2-PEI electrodes exhibit a high discharge capacity of 150.6 mAh g−1 at 5C and outstanding capacity retention of 96.9 % after 100 cycles at 1C. Moreover, further cycle tests in harsh environments, such as high mass loading and operating temperature, demonstrate that the ceMoS2-PEI layer coating more effectively improves the structural and thermal stability of the Ni-rich NCM in harsh environments.

Effect of sodium and yttrium co-doping on electrochemical performance of LiNi0.8Co0.15Al0.05O2 cathode material for Li-ion batteries: Computational and experimental investigation

LiNi0.8Co0.15Al0.05O2 (NCA) has attracted a lot of attention owing to its high voltage, specific energy density, and specific capacity. However, the cycle durability of the NCA material is still a challenge. Oxygen evolution, migration of nickel cations to the lithium layers (cation mixing), and the destruction of the layered structure of NCA are the most important reasons for thermal and structural instability, reducing capacity, and increasing impedance. Doping is one of the most effective ways to improve the thermal and structural stability of the NCA. In this study, the addition of sodium (Na) on Li-site and yttrium (Y) on metal-site, as well as the simultaneous addition of these elements to NCA material, were investigated experimentally and theoretically. For the first time, we proposed a framework for parameterization of the structural and thermal stability of NCA during the lithiation/delithiation process in terms of first-principle density functional theory (DFT) calculations. It is shown that variation in the Bulk modulus can reflect structural responses, and the calculated Bader charge on oxygen atoms is directly connected to thermal stability concerns. The computational results confirmed the positive effect of Na+ and Y3+ on the structural and thermal stability of the NCA cathode systematically. Following those outcomes, different percentages of the dopants were added to the cathode material experimentally, and electrochemical tests such as cyclability, electrochemical impedance spectroscopy, cyclic voltammetry, and rate capability were performed. The electrochemical tests revealed that in single-doped samples, the optimal amount of Na+ and Y3+ was 0.5 % (mol%), and in co-doped samples, 0.5 % of each dopant (0.5Na-0.5Y-NCA) produced the best results. The optimal 0.5Na-0.5Y-NCA sample retained 92.34 % of its capacity after 100 charge and discharge cycles at a rate of 0.5C, compared to 67.11 % for the pristine NCA. The cooperative addition of sodium and yttrium with different mechanisms such as reducing released oxygen, reducing the formation of insulating compounds, increasing the diffusion coefficient, reducing charge transfer resistance, and improving structural and thermal stability demonstrated synergistic effects on stabilizing the layered structure and improving cycling performance. The underlying mechanisms of observed experimental improvements were interpreted and discussed according to computational outcomes.

A stable dual LiAlO2/Li2SiO3 coating LiNi0.8Co0.1Mn0.1O2 cathode towards ultra-long-life and wide-temperature lithium-ion battery

Ni-rich layered LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material offers great potential for widespread applications due to its high capacity, non-toxicity, and low cost. However, the instability of the structure, large polarization and occurrence of side reactions during charge-discharge cycles greatly restrict the performance of LiNi0.8Co0.1Mn0.1O2. The stability of NCM811 can be improved through surface coating, but single-phase coating cannot achieve both high electronic conductivity and enhanced Li+ diffusion. Herein, LiAlO2 and Li2SiO3 are applied to prepare dual coating NCM811 (AS-NCM811) and build 3D Li+ diffusion channels and surface protection to improve both Li+ diffusion efficiency and electronic conductivity of NCM811. In addition, using LiAlO2 and Li2SiO3 in AS-NCM811 can enhance structural stability and reduce the likelihood of undesired side reactions occurring, which is verified by ex-situ X-ray diffraction and transmission electron microscopy. As a result, the AS-NCM811-based battery exhibits a remarkable cyclic ability and rate performance in widen temperature range (room temperature (RT) to 55 °C). AS-NCM811 shows an RT initial discharge capacity of 180.8 mAh g−1, while achieve a high-capacity retention of 92.6 % (100 cycles, 1C). Even at 55 °C, AS-NCM811 also retains 68.4 % of its capacity (143.5 mAh g−1) after 200 cycles under 1C. Overall, these findings pave a novel dual-coating way for the application of Ni-rich layered cathodes in high energy-density lithium-ions battery.

Improving the electrochemical performance of ultrahigh-nickel-based layered LiNi0.95Mn0.05O2 cathode through cobalt modification for next-generation high-energy Li-ion batteries

Nickel-rich cobalt-free layered cathode materials are expected to meet the urgent demand for high-energy batteries at an adorable cost. However, as the nickel content increases and cobalt content decreases, layered cathode materials suffer from serious structure degradation and capacity fade during cycling. The large amount of residual lithium in nickel-rich materials also brings difficulties to industrial manufacturing and challenges battery safety. In this work, well-formed crystal cobalt-contained coatings with surface cobalt-doped ultrahigh-nickel-based layered LiNi0.95Mn0.05O2 cathode material is synthesized through solid solution and post-heat treatment with Co(OH)2, during which the residual lithium is significantly consumed. The optimized sample acquired at 650 ℃ shows an increased discharge capacity of 221.2 mAh g−1 from 219 mAh g−1 of the pristine one at 0.1 C and the capacity retention is enhanced from 72.6% to 83.2% for 100 cycles at 0.5 C.

Enhanced Electrochemical Performance of a Ti-Cr-Doped LiMn1.5Ni0.5O4 Cathode Material for Lithium-Ion Batteries.

Ti, Cr dual-element-doped LiMn1.5Ni0.5O4 (LNMO) cathode materials (LTNMCO) were synthesized by a simple high-temperature solid-phase method. The obtained LTNMCO shows the standard structure of the Fd3®m space group, and the Ti and Cr doped ions may replace the Ni and Mn sites in LNMO, respectively. The effect of Ti-Cr doping and single-element doping on the structure of LNMO was studied by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) characteristics. The LTNMCO exhibited excellent electrochemical properties with a specific capacity of 135.1 mAh·g-1 for the first discharge cycle and a capacity retention rate of 88.47% at 1C after 300 cycles. The LTNMCO also has high rate performance with a discharge capacity of 125.4 mAh·g-1 at a 10C rate, 93.55% of that at 0.1C. In addition, the CIV and EIS results show that the LTNMCO showed the lowest charge transfer resistance and the highest diffusion coefficient of lithium ions. The enhanced electrochemical properties may be due to a more stable structure and an optimized Mn3+ content in LTNMCO through TiCr doping.

Improving Cyclic Stability and Rate Performance of Lithium Ion Batteries Using La3+ Modified LiNi0.6Co0.2Mn0.2O2 Cathode Materials

Improving Cyclic Stability and Rate Performance of Lithium Ion Batteries Using La3+ Modified LiNi0.6Co0.2Mn0.2O2 Cathode Materials

Effect of thickness and uniformity of LiNbO3-coated layer on LiNi0.5Co0.2Mn0.3O2 cathode material on enhancement of cycle performance of full-cell sulfide-based all-solid-state batteries

Although LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode active material (CAM) is considered to have application potential in sulfide-based all-solid-state batteries (ASSBs), CAM/solid electrolyte interfacial instability remains a significant limiting factor. To effectively improve the interfacial stability and long-term cycling performance, NCM523 cathode material was coated with LiNbO3 layers of different thicknesses and uniformity. As a result, the cycle performance was greatly enhanced by increasing the thickness and uniformity of the LiNbO3-coated layer. Our findings further demonstrate that a thick (≥9 nm) and uniform coated layer (surface without uncoated area) displays outstanding electrochemical performance, especially cycle stability (capacity retention of 85.1% after 300 cycles at 60 °C), indicating that this strategy is very effective for constructing high-performance NCM cathodes for sulfide-based ASSBs. Moreover, the performance improvement mechanism was investigated by electrochemical impedance spectroscopy (EIS) combined with XPS and TEM-EDX analysis. The findings reveal that controlling the thickness and uniformity of the coating material plays a crucial role in the effective suppression of interface side reactions and resultant performance degradation in NCM cathodes.

Construction of Cu-Zn Co-doped layered materials for sodium-ion batteries with high cycle stability

Due to its high operational voltage and energy density, P2-type Na0.67Ni0.3Mn0.7O2 has become a leading cathode material for sodium-ion batteries (SIBs), which is an ideal option for large-scale energy storage. However, the practical application of P2-type Na0.67Ni0.3Mn0.7O2 is limited by the capacity constraints and unwanted phase transitions, presenting significant challenges to the widespread application of SIBs. To address these challenges and optimize the electrochemical properties of the P2 phase cathode material, this study proposes a Cu and Zn co-doped strategy to improve the electrochemical performance. The incorporation of Cu/Zn can stabilize the P2-phase structure against P2-O2 phase transitions, thus enhancing its electrochemical properties. The as-obtained P2-type Na0.67[Ni0.3Mn0.58Cu0.09Zn0.03]O2 cathode material shows an impressive cycling stability, maintaining 80% capacity retention after 1000 cycles at 2 C. The cyclic voltammetry (CV) tests show that the Cu2+/Cu3+ redox reaction is also involved in charge compensation during the charge/discharge process.

Synthesis and enhanced electrochemical properties of LiNi0.6Co0.2Mn0.2O2 cathode materials via SDBS-assisted hydrothermal method

Synthesis and enhanced electrochemical properties of LiNi0.6Co0.2Mn0.2O2 cathode materials via SDBS-assisted hydrothermal method

A feasible process for recycling valuable metals from LiNi0.5Co0.2Mn0.3O2 cathode materials of spent Li-ion batteries

ABSTRACT The recycling of cathode materials for spent NCM has always been a major concern for the energy industry. However, among the current processing methods, the general leaching efficiency of Li is between 85% and 93%, with much room for improvement. The recovery of Ni, Co and Mn requires a high cost of secondary purification. In this study, to recycle the NCM cathode material, a route of sulphated reduction roasting – selective Li water leaching – efficiency acid leaching of Ni, Co, Mn – extraction separation – crystallisation was adopted. The results showed that after roasting (a temperature of 800 °C, a reaction time of 90 min, a carbon content of 26%, and a sulphuric acid addition of nH2SO4:nLi = 0.85), Li water leaching efficiency was 98.6%, followed by acid leaching of Ni, Co and Mn at around 99%. Mn, Co were extracted with Di-(2-ethylhexyl) phosphoric acid and 2-Ethylhexyl phosphonic acid mono-2-ethylhexyl ester respectively to obtain Ni, Co, Mn solutions, which eventually were crystallized for manganese sulphate, cobalt sulphate, lithium carbonate and nickel sulphate products, with high purity of 99.40%, 98.95%, 99.10%, and 99.95%. The results of this study improved the leaching efficiency of Li and were closely linked to the actual industrial preparation of Ni, Co and Mn sulphates, providing a feasible and promising basis for spent NCM cathode materials industrial recovery.