Nickel Cathode Research Articles

Oxygen surface exchange properties and electrochemical activity of lanthanum nickelates

Oxygen surface exchange properties of lanthanum nickelates La2NiO4+δ, La3Ni2O7-δ and La4Ni3O10-δ (LNOs) have been investigated using the Pulsed Isotope 18O/16O Exchange (PIE) technique in the temperature range 300–700 ​°C. The evaluation of the oxygen exchange rate from these lanthanum nickelates was conducted by measurement of isotope fractions 18O2, 16O18O, and 16O2 in the effluent pulse at the exhaust from the reactor with a packed bed. The rates of oxygen heterogenous surface exchange (rH), dissociative adsorption (ra) and incorporation (ri) were calculated. The oxygen surface exchange was found to vary between the three nickelates, with rH decreasing between samples La3Ni2O7-δ ​> ​La4Ni3O10-δ ​> ​La2NiO4+δ, which was attributed to a decreasing presence of Ni cations on the particle surfaces. Despite possessing the lowest oxygen surface exchange, La2NiO4+δ had the best electrode electrochemical performance, which was attributed to highly mobile interstitial oxygen atoms leading to the largest ri (surface oxygen incorporation rate into the bulk) of the nickelates. This study reveals the key limiting factors determining lanthanum nickelate cathode performance in SOFCs, and we suggest avenues to improve these materials towards functional cathodes in devices.

Synergistic effect of Al–B co-doping to boost the LiNi0.9Co0.05Mn0.05O2 properties in lithium-ion batteries

The high nickel and low cobalt cathode material, LiNixCoyMn1-x-yO2 (x>80%, y<10%), has become one of the preferred materials in next-generation new energy vehicles due to its high energy density, but its wide use in the market is limited because of poor structural stability triggered by the high nickel content. In this work, the 0.002 mol of Al3+ and 0.001 mol of B3+ co-doping LiNi0.9Co0.05Mn0.05O2 cathode materials (0.2Al-0.1B-LNCM90) were successfully synthesized by simple solid-phase sintering, which were confirmed by ICP, EDS and XPS. The results showed that the modified samples integrate the effect of Al-doping and B-doping. On the one hand, B occupied the tetrahedral gap of the oxygen array in the transition metals (TM) and lithium layers, which increases the lattice parameter c. On the other hand, the strong Al–O bond reduced the evolution of lattice O. The cell assembled with the 0.2Al-0.1B-LNCM90 transferred an initial discharge capacity of 227 mAh g−1 at 0.1 C between 2.75 and 4.3 V, with a discharge capacity of 176 mAh g−1 after 100 cycles, which is higher than that of 101 mAh g−1 for the pristine material. Moreover, it also delivered a superior discharge specific capacity of 169 mAh g−1 at 5 C, compared to 128 mAh g−1 for the pristine material.

New insight on correlation between the electrochemical stability and the thermal stability of high nickel cathode materials

Cycle stability and thermal safety are critical to the commercialization of nickel-rich layered materials, yet whether there is a potential correlation between these two factors is still controversial. Herein, the relationship between the cycle stability and thermal stability of nickel-rich cathode materials have been systematically studied through five different calcination temperatures of Li[Ni0.83Co0.12Mn0.05]O2 (NCM83) cathode materials. The research results confirm that the cycle stability and thermal safety of nickel-rich cathode materials do not necessarily show a positive correlation. Actually, with the calcination temperature elevated, the thermal stability of the NCM83 is enhanced, while the cycle stability is degraded. This opposite correlation is not commonly reported in previous literatures. In this work, systematical characterizations demonstrate that under the experimental conditions, the capacity retention of NCM83 is mainly determined by the Li/Ni cation disorder and H2-H3 irreversible phase transition, which is optimal at lower calcination temperature. Meanwhile, the thermal stability is mainly impacted by thermal expansion characteristics and interfacial stability of cathode material, and it is dramatically improved by the mechanical strength of the secondary particles reinforced at high calcinated temperature. This study provides some new insights on understanding and designing of the high-energy cathode materials with long cycle-life and superior safety.

Stabilization of High Nickel Cathode Materials with Core-Shell Structure via Co-precipitation Method

Stabilization of High Nickel Cathode Materials with Core-Shell Structure via Co-precipitation Method

Magnetic Separation as Part of New Nickel Concentrate Processing Technology at Kola MMC: Performance Analysis and Upgrade. Part I

Kola Mining and Metallurgical Company has recently introduced significant changes into its processing circuits that deal with sulphide nickel concentrates, the product of converter matte separation. They help reduce both losses and operating costs, as well as generate extra revenues due to enhanced product quality. At the same time, the upgrades done to the production equipment and the adoption of electrowinning process for obtaining high-grade nickel cathodes at Norilsk Nickel sites require that the tube kiln nickel powder, which is subjected to chlorine dissolution at Kola MMC&rsquo;s electrowinning plant, was of particular quality. The key quality requirements concerning the tube kiln nickel powder include the presence of carbon component and slag-forming impurities&nbsp;(SiO2, Al2O3 and others), which impact the performance of the followinghydrom tallurgical process stage, as well as the metal content of the resulting middlings. Due to additional conditions set, concentration techniques should be used to enhance the quality of the middlings. The drawbacks of the existing magnetic separation line, as well as the peculiar behaviour of the raw materials that revealed itself during the start-up, made the line upgrade necessary. This paper examines certain production flowsheets and looks at improving the quality of the final product by separating materials based on their differing magnetic properties.

A freeze-thaw molten salt battery for seasonal storage

Grid-level storage of seasonal excess can be an important asset to renewable electricity. By applying the freeze-thaw thermal cycling strategy, here, we report Al-Ni molten salt batteries with effective capacity recovery over 90% after a period of 1–8 weeks as a proof-of-concept. We explore three activation methods of the nickel cathode in a molten-salt battery: (1) heat treating the cathode granules under H2/N2, (2) incorporating a partially charged NiCl2/Ni cathode, and (3) doping the molten salt electrolyte with sulfur. In particular, sulfur doping, a cost-efficient method suitable for large-scale applications, is not only effective in activating the Ni cathode initially but also invaluable for energy retention during thermal cycling. Overall, these Al-Ni molten salt batteries under thermal cycling show high retention in cell capacity over weeks, setting a direction for scalable seasonal storage.

Probing the improved stability for high nickel cathode via dual-element modification in lithium-ion

One of the major hurdles of nickel-rich cathode materials for lithium-ion batteries is the low cycling stability, especially at high temperature and high voltage, originating from severe structural degradation, which makes this class of cathode less practical. Herein, we compared the effect of single and dual ions on electrochemical performance of high nickel (LiNi0.88Mn0.03Co0.09O2, NMC) cathode material in different temperatures and voltage ranges. The addition of a few amounts of tantalum (0.2 wt%) and boron (0.05 wt%) lead to improved electrochemical performance. The co-modified LiNi0.88Mn0.03Co0.09O2 displays an initial discharge capacity of 234.9 mAh/g at 0.1 C and retained 208 mAh/g at 1 C after 100 cycles at 45 °C, which corresponds to a capacity retention of 88.5%, compared to the initial discharge capacity of 234.1 mAh/g and retained capacity of 200.5 mAh/g (85.6%). The enhanced capacity retention is attributed to the synergetic effect of foreign elements by acting as a surface structural stabilizer without sacrificing specific capacity.

Wrinkled and flexible N-doped MXene additive for improving the mechanical and electrochemical properties of the nickel-rich LiNi0.8Co0.1Mn0.1O2 cathode

In this work, the wrinkled, flexible, and layered nitrogen-doped Ti3C2Tx (shorten as N-MXene) is synthesized by using cyanamide as N-dopants. The changeable (002) plane spacing and the attached functional groups of N-MXene are detected by XRD and XPS analyses in details, respectively. The microscopic morphology of N-MXene is characterized by SEM and TEM, which demonstrates its wrinkled and flexible characteristics. When the wrinkled N-MXene being added into the LiNi0.8Co0.1Mn0.1O2 (NCM811) as conductive additive, the attained electrodes obtain enhanced electrochemical performances at the appropriate weight ratio (namely 2.5-N-MXene with 2.5 wt.%). The 2.5-N-MXene delivers “extra” capacity of 226.9 mAh/g at 0.1 C (20 mA/g) current density. The “extra” capacity is assigned to Li ions intercalation/extraction from the wrinkled/flexible/layered N-MXene. Moreover, based on the analyses of CV and dQ/dV curves, the wrinkled/flexible N-MXene additive could effectively inhibit the phase transition of M↔H2 of NCM811 and alleviate the volume change of the particles in the circulation. From DFT simulation, the N-MXene is more capable of preventing Ni/Co/Mn from dissolving and migrating to the negative electrode to form dendrites through adsorption. Therefore, the N-MXene should be a very competitive conductive agent to improve the mechanical and electrochemical properties of high nickel cathode materials.

Organic Borate-Rich Interphase Improves the Cycling Stability and Rate Performance of High Nickel Cathode

Organic Borate-Rich Interphase Improves the Cycling Stability and Rate Performance of High Nickel Cathode

Behaviour of SiO2 during a new process applied to nickel concentrate from matte separation at Kola MMC

Kola MMC has built a new nickel site that relies on chlorine leaching of nickel powder followed by electrowinning of nickel with insoluble anodes. After the new site had been commissioned, the operations of the refining facility saw changes, the electric anode furnaces were taken out of service, and a magnetic separation section was commissioned. The latter helps remove unreacted coal, metal oxides and other non-magnetic components from the tube kiln nickel powder thus ensuring its optimized quality. At the same time, once the electric furnaces had been removed from the process, it created the need for strict control over carbon and slag-forming constituent concentration in the nickel powder that goes to the chlorine leaching section. This paper looks at the history of the process behind the production of roasted nickel &ndash; the product of fluidized-bed furnaces &ndash; and describes the revamping stages witnessed by the Kola MMC site. The paper also analyzes certain features related to the current processing of nickel concentrates &ndash; from nickel matte separation to the production of nickel metal powder. The latter is further sent for chlorine leaching and in the presence of chlorine gas it gets dissolved. Then copper, iron, zinc and cobalt are removed from the resultant liquor and the purified sulphate-chloride solution goes in the electrolysis cells where high-purity nickel cathodes are produced. The authors analyzed the compositions of the key components in the studied materials of the nickel processing line. Special attention is given to the behaviour of silicon dioxide as one of the impurities causing most problems in the new process.

Prussian Blue Nanolayer-Embedded Separator for Selective Segregation of Nickel Dissolution in High Nickel Cathodes.

Transition metal layered oxides (LiNixCoyMn1-x-yO2, NCM) have been considered as one of the most promising cathodes for lithium-ion batteries used in long-mileage electric vehicles and energy storage systems. Despite its potential interest, dissolved transition metal (TM) ions toward anode sides can catalyze parasitic reactions such as electrolytic decomposition and dendritic Li growth, ultimately leading to catastrophic safety hazards. In this study, we demonstrate that Prussian Blue (PB) nanoparticles anchored to a commercial PE separator significantly reduce cell resistance and effectively suppress TM crossover during cycling, even under harsh conditions that accelerate Ni dissolution. Therefore, using a PB-coated separator in a harsh condition to intentionally dissolve Ni2+ ions at a high cutoff potential of 4.6 V, NCM||graphite full cells maintain 50.8% of their initial capacity at the 150th cycle. Scalable production of PB-coated separator through the facile synthetic methods can help establish a new research direction for the design of high-energy-density batteries.

Insights into carbon production by CO2 reduction in molten salt electrolysis in coaxial-type reactor

With carbon capture and utilization (CCU) technologies, it is possible to take CO2 from air and transform it into valuable carbon products, such as graphene and nanotubes. In this study, CO2 was reduced to solid carbon by molten lithium carbonate salt electrolysis. The reactor used for the electrolysis was a coaxial-type unit, where a cylindrical nickel cathode was placed inside a cylindrical stainless steel vessel; such a coaxial-type reactor has not been used before for molten salt electrochemical reduction of CO2. This reactor design allows studies of voltage-current characteristics, which have previously not been conducted for this specific process. As a result, voltage efficiency of this process could be determined along with effect of temperature to cell voltage. Based on these results it is evident that accurate temperature control is crucial in terms of energy efficiency of the process. Data monitoring revealed a high accuracy of temporal temperature control. Great temperature differences were observed spatially. Thermoneutral voltage from the process was determined to be 1.02 V. For this electrochemical process studied, carbon nano-onions (CNOs) were obtained as a main product. Identification of the product was carried out based on Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) analyses. Results also showed that iron, chromium and nickel metals are released during electrolysis. Iron and chromium can only be released from the stainless steel anode, as nickel can come from anode or cathode.

Fluorinated cyclic siloxane additives for high energy density Li-ion batteries with high nickel cathodes and silicon–carbon anodes

It is a big challenge to enhance the interfacial stability and cycling performance of high nickel cathodes and silicon carbon anodes in Li-ion batteries with high energy density. In this work, we propose a new type of fluorinated cyclic siloxane additive, 1,3,5-tris(3,3,3-trifluoropropyl)methylcyclotrisiloxane (3FO), to improve cycling stability of high nickel cathodes (NCM811) and silicon carbon anodes (Si–C). The Li/NCM811 cells with Baseline electrolytes+1 wt% 3FO have a significant capacity retention (63.3%) after 400 cycles at 1C current rate than that with Baseline electrolytes (37.5%). Furthermore, the Li/Si–C cells in the combined electrolyte of 3FO and fluoroethylene carbonate (FEC) can be cycled well, and the capacity retention of Si–C/NCM811 full cells is as high as 93.3% after 800 cycles at 1C/1C rate. Our results show that 3FO can scavenge part of the HF in the electrolyte and stabilize the interface structure. The results of EIS, SEM and TEM show that 3FO can help to generate a stable and uniform CEI film, suppress the increase in impedance and reduce cell polarization. Theoretical calculations, NMR and XPS studies found that 3FO can result in ring-opening reactions during cycling, forming a stable interface film with SiO x and C–F, and improving the electrochemical stability of lithium-ion batteries. 3FO additives can scavenge part of the HF and help to generate a stable and uniform CEI film, which improve cycling stability of high nickel cathodes (NCM811) and silicon carbon anodes (Si–C). • A novel additives of 1,3,5-tris(3,3,3-trifluoropropyl)methylcyclotrisiloxane (3FO). • 3FO scavenges HF in electrolytes and generates surface films on electrodes. • The Si–C/NCM811 cells with 3FO/FEC additives show enhanced performance.

Understanding the Failure Mechanisms of LiNixCoyMnzO2 Cathodes through Surface Reactions with the Electrolyte

Layered LiNixCoyMnzO2 (NCM) cathodes are one of the most widely used cathode materials for Lithium-ion batteries (LIB) with a high theoretical capacity and relatively high voltage window. Increasing the Nickel content and the cycling voltage can increase the capacity and the energy density at a lower cost, but these high Nickel cathodes cycled to a higher cut off voltage have poor cycling stability. The cause of this rapid capacity decrease has been attributed to continuous growth of the anode solid electrolyte interphase (SEI) due to transition metal deposition on the anode surface and impedance growth on the cathode surface. Recent studies have also attributed acid mediated electrolyte degradation reactions that degrade the SEI with extended cycling for this rapid capacity fade.In this study merits of these 3 theories are being investigated through various quantitative analysis techniques including, ICP-MS, solution NMR, XPS and EIS. Full cells were constructed using graphite as the negative electrode and NCM cathodes with different Nickel contents. These cells contain the same base electrolyte formulation (1.2M LiPF6 and EC: EMC, 3:7) and they were cycled at different temperatures and voltages to compare the correlation between nickel content, voltage and capacity fade.

Fouling and corrosion of electrode plates in nickel cadmium batteries

The aim of this study is investigation of fouling propensity in nickel cadmium electrodes after degradation of alkaline-electrolyte from rich-hydroxide to rich-carbonate along with time. Gradually, CO2 absorption from the air into the alkaline electrolyte leads to the destruction of electrodes and the formation of precipitated layers resulting in reduction of electrical capacity and life time of batteries. Based on the microscopic observations (SEM), spectroscopic evidences (FTIR and XRD) and thermal experiments (TG-DTA) significant damages and fouling phenomena were categorized as: salt islands, graphite films, etched graphite, cadmium dendrites, cadmium oxide/sulfide and cathodic corrosion. The experimental results revealed that nickel cathodes have experienced more surface damages with respect to cadmium anodes. Although the anode is the source of cadmium species, however the fouling layers of cadmium oxide and cadmium sulfide were assigned to be the main causes of cathode damage, leading to the decreasing of electrode current and the increasing of internal resistance of the cells. On the other hand, the main damage on the surface of anode electrode was attributed to graphite coatings and cadmium hydroxide stripped from the cathode. The microscopic observations showed that almost 2% of cathode surface was corroded, while the anode surface had experienced no corrosion.

Electrochemical Behaviors of Consumable Ti2CO@Al2O3 Anode for Ti Extraction by USTB Process

USTB technology is widely considered as a low-cost and environmentally-friendly method for titanium extraction from a consumable TiCxOy anode. It is expected to directly prepare TiCxOy by selective carbothermal reduction of titanium ores, not pure TiO2. However, impurities in titanium ores, particularly Al2O3, may affect the electrochemical dissolution of TiCxOy and Ti extraction. In this work, the effects of Al2O3 impurity on the preparation and dissolution behaviors of Ti2CO are studied. It is found that the existence form of Al2O3 is not changed during carbothermal reduction. With the increase of Al2O3 content, the conductivity of Ti2CO anode slightly decreases from 143.1 to 131.6 S cm−1 and the anodic polarization curves of Ti2CO@Al2O3 shifts to the positive direction due to the increase of dissolution resistances. Al2O3 in Ti2CO@Al2O3 anode will drop into molten salts to form anode slime during USTB process. On both liquid Zn and solid nickel cathodes, Ti is electrodeposited, which is not affected by Al2O3 impurity. Therefore, it is confirmed that typical Al2O3 impurity has no obvious effect on the electrochemical dissolution of Ti2CO anode and Ti extraction. The advanced USTB process is expectedly developed by the selective carbothermal reduction of titanium ores to prepare Ti2CO anode.

Improvement of cycle performance of the high nickel cathode material LiNi0.88Co0.07Al0.05O2 for lithium-ion batteries by the spray drying of V2O5

LiNixCoyAl1−x-yO2 (NCA), as high nickel cathode material, has a high capacity and is one of the most promising cathode materials for lithium-ion batteries. However, the disadvantages such as more residual lithium compounds and serious capacity decay have hindered the industrial application of this material. In order to reduce the residual lithium compound on the surface of the material and restrain the capacity degradation, we designed and prepared a high nickel cathode material by pretreatment washing and subsequent spray drying, which has high cycle life and high discharge specific capacity. Compared to the first discharge specific capacity of 196.6 mAh g−1(0.2 C) for the raw material and 131.4 mAh g−1 after 100 cycles of 1 C, the discharge specific capacity of the modified sample 2V2O5@NCA was increased to 210.4 and 163.8 mAh g−1, respectively. Microstructure observation revealed that V2O5 not only uniformly covers the surface of the secondary particles, but also the presence of electrochemically active LiV3O8, which avoids the direct contact between the active material and electrolyte, thus significantly suppressing the interfacial side reactions between the cathode material and electrolyte and improving the structural stability of the material. Our exploration may pave a way for developing high cycle stability of high nickel cathode materials.

Electrophotocatalytic Si–H Activation Governed by Polarity-Matching Effects

Electrophotocatalytic Si–H Activation Governed by Polarity-Matching Effects

Rechargeable Lithium Metal Pouch Cell Development

Commercially available Li-ion batteries using graphite or graphite-silicon blended anodes are currently approaching a cell level specific energy of 300 Wh kg−1. The use of lithium metal instead as an anode an intriguing possibility to further increase cell level specific energies to 400 Wh kg−1 and beyond. Lithium is an ideal anode because it is the lightest metal and highly electronegative. However, attempts to commercialize cells using lithium metal anodes have been slowed by poor cycle life and safety issues. This is because nonuniform lithium plating leads to the growth of dendrites that cause loss of active lithium and can eventually lead to internal cell shorts. Safe cell cycle life must be improved to 50-100 cycles for special purpose applications like unmanned aerial vehicles, >300 cycles for portable power applications and >1000 cycles for electric vehicle applications.The performance of prototype cells developed at EaglePicher Technologies using lithium metal anode will be highlighted. The figure below on the left shows the specific discharge energy of a 2.5 Ah prototype pouch cell using a lithium anode, high nickel cathode and nonaqueous electrolyte. The cell demonstrates an extremely high specific energy of >400 Wh kg−1 at low rates. The effect of electrolyte on capacity retention is shown in the figure below on the right. The optimized electrolyte demonstrates good retention to >50 cycles. This presentation will focus on design considerations for pouch cells with lithium anodes, as well as improving the cycle life and safety characteristics of these cells. Prototype performance data including cycle life, rate capability, temperature effects and safety testing will be presented.EaglePicher Technologies would like to acknowledge the US Army DEVCOM C5ISR Center in Aberdeen Proving Ground, Maryland for funding this research. Figure 1

The Improved Interfacial and Thermal Stability of Nickel‐Rich LiNi0.85Co0.10Mn0.05O2 Cathode in Li‐Ion Battery via Perovskite La4NiLiO8 Coating

AbstractCapacity attenuation caused by Ni dissolution and interface instability during cycling is a major challenge because it limits the application of high Ni ternary cathode materials in Li‐ion batteries. In this paper, ternary LiNi0.85Co0.10Mn0.05O2 cathode with high nickel content was prepared by co‐precipitation method, and then was coated with perovskite La4NiLiO8 via the simple thermochemical method. The analysis of the images of transmission electron microscope (TEM) showed that the coating is uniformly covered on the surface of NCM85 material with a thickness of 5 nm. Compared to uncoated sample, the La4NiLiO8‐coated LiNi0.85Co0.10Mn0.05O2 material shows lower electrochemical impedance and better cyclic stability, the initial kinetic diffusion coefficient and the interface stability of the prepared material are greatly improved. Meanwhile, the problems of Li+/Ni2+ mixing are also been solved. This work provides a new strategy for improving the interface and thermal stability of the nickel cathode material of Li‐ion battery in the future.