Ternary Cathode Research Articles

Effects of Ti4+ doping on electrochemical properties of LiNi0.815Co0.15Al0.035O2 cathode materials

The high nickel ternary cathode materials LiNi0.815Co0.15Al0.035O2 (NCA) have been widely used in Li-ion batteries due to their high energy density, low cost, and little environmental pollution. However, it suffers from rapid capacity degradation and poor charging rate. In this work, Ti4+ doping NCA cathode materials are prepared by the high-temperature solid-state method. The results show that 0.5%Ti-NCA has a lower cationic mixing degree and better cycling performance. The capacity retention rate of 100 cycles is 98.91% and 96.59% at current densities of 0.5 C and 1.0 C, respectively. The CV and EIS test results show that 0.5%Ti-NCA has lower polarization and higher lithium ion diffusion coefficient DLi+(8.43×10−14 cm2/S) after 100 cycles, while Pure-NCA only has 6.92×10−15 cm2/S, which effectively enhances the electrochemical properties of NCA cathode materials.

Dynamically constructing robust cathode-electrolyte-interphase on nickel-rich cathode by organic boron additive for high-performance lithium-ion batteries

Nickel-rich ternary cathode materials LiNi0.8Co0.1Mn0.1O2 (NCM811) have attracted broad attention due to their high voltage and high energy density for lithium-ion batteries. However, rapid capacity decay due to unstable particle surface inhibit the application. Artificial cathode electrolyte interface (CEI) is undoubtedly a more effective and simpler way to solve this issue. Here, stable and highly conductive in situ CEI is designed using a low-cost organic boron additive isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (ITD). Higher occupied molecular orbital energy endows ITD ability to participate in forming CEI. ITD-contained CEI can reduce nickel dissolving, resulting in a lower self-discharge rate, which is benefit from the uniform and stable CEI on the NCM811 surface. As expected, ITD-based CEI can restrain NCM811crystal cracking in Li||NCM811 half batteries, improving capacity retention from 29.4 % to 93.0 % after 200 cycles at 1C (1C = 200 mA g−1). It is worth mentioning that ITD–derived CEI is conducive to ion migration, which improve the rate capacity retention from 91.5 % to 95.5 %.

Nickel-rich ternary cathode material as a novel capping layer to improve lithium iron phosphate electrochemical performance

Nickel-rich ternary cathode material as a novel capping layer to improve lithium iron phosphate electrochemical performance

Conductive chitosan/polyaniline hydrogel: A gas sensor for room-temperature electrochemical hydrogen sensing

Hydrogen (H2) has been deemed a source of energy for both stationary and mobile applications to contribute to lowering carbon emissions due to its abundance (which can be extracted from various compounds), environmental friendliness, and high energy density. However, H2 gas is highly flammable and has a fast burning rate. Consequently, the need to ensure human safety and environmental preservation necessitates the development of hydrogen sensors that exhibit heightened sensitivity, a reduced detection threshold, and quick response times. Herein, we present the synthesis of a ternary hydrogel composite, chitosan-crosslinked poly(acrylic acid)-based polyaniline hydrogel (Cs-cl-pAA/PANI), which was developed to function as a cathode material in hydrogen sensing applications. The structural and optical properties of ternary cathode materials were evaluated using various analytical techniques, and hydrogen sensing was studied using electrochemical techniques. The electrochemical sensing characteristics of the hydrogel matrix were improved by including polyaniline (PANI) as a result of the overlapping of localised π-electrons in the p-orbitals. The sensitivity of the Cs-cl-pAA/PANI hydrogel was determined to be 48.7845 μA M, with a reaction time of 0.6s, recovery time of 2s, and detection limit of 3.682 μM. The sensor also exhibited outstanding restoration and repeatability.

A Study on the Microstructure Regulation Effect of Niobium Doping on LiNi0.88Co0.05Mn0.07O2 and the Electrochemical Performance of the Composite Material under High Voltage.

High-nickel ternary materials are currently the most promising lithium battery cathode materials due to their development and application potential. Nevertheless, these materials encounter challenges like cation mixing, lattice oxygen loss, interfacial reactions, and microcracks. These issues are exacerbated at high voltages, compromising their cyclic stability and safety. In this study, we successfully prepared Nb5+-doped high-nickel ternary cathode materials via a high-temperature solid-phase method. We investigated the impact of Nb5+ doping on the microstructure and electrochemical properties of LiNi0.88Co0.05Mn0.07O2 ternary cathode materials by varying the amount of Nb2O5 added. The experimental results suggest that Nb5+ doping does not alter the crystal structure but modifies the particle morphology, yielding radially distributed, elongated, rod-like structures. This morphology effectively mitigates the anisotropic volume changes during cycling, thereby bolstering the material's cyclic stability. The material exhibits a discharge capacity of 224.4 mAh g-1 at 0.1C and 200.3 mAh g-1 at 1C, within a voltage range of 2.7 V-4.5 V. Following 100 cycles at 1C, the capacity retention rate maintains a high level of 92.9%, highlighting the material's remarkable capacity retention and cyclic stability under high-voltage conditions. The enhancement of cyclic stability is primarily due to the synergistic effects caused by Nb5+ doping. Nb5+ modifies the particle morphology, thereby mitigating the formation of microcracks. The formation of high-energy Nb-O bonds prevents oxygen precipitation at high voltages, minimizes the irreversibility of the H2-H3 phase transition, and thereby enhances the stability of the composite material at high voltages.

Enhancement in electrochemical properties of sodium-doped LiNi0.815Co0.15Al0.035O2 cathode

Lithium-ion batteries (LIBs) as energy storage devices have been booming recently to fill the demand for energy requirements. High‑nickel ternary cathode material LiNi0.815Co0.15Al0.035O2 (NCA), extremely possible to be the next generation of cathode materials for applications due to its high energy density, low cost, and environmental friendliness. However, the rate capability and cycling stability of this cathode material is mediocre. In this work, NCA-based cathode materials have been modified by sodium (Na+) doping through a high-temperature solid-state reaction, the results show that Na+-doping can effectively improve the electrochemical performance of NCA. Electrochemical test results show that Na+-doping improves Li+ diffusion coefficient, inhibits NCA polarization, and reduces the charge transfer impedance. As-prepared 2%Na-NCA at the current density of 1.0C shows a discharge-specific capacity of 149.16 mAh/g and a retention rate of 96.49% after 100 cycles, but the retention rate of the Pure-NCA was (84.47%). Furthermore, 2% Na-NCA shows 121.07 mAh/g at 5.0C, with an increase of 27.05 mAh/g over the Pure-NCA (94.02 mAh/g). The results of the study showed that doping with sodium ions can effectively improve the rate capabilities and cycling stability of NCA.

Realizing Dual Functions through Y2O3 Modification to Enhance the Electrochemical Performance of LiNi0.8Co0.1Mn0.1O2 Material

In recent years, the remarkable energy density of high-nickel ternary materials has captured considerable attention. Nevertheless, the high-nickel ternary cathode material encounters several challenges, including cationic mixing, microcrack formation, poor cycling capability, and limited thermal stability. Coating, as a viable approach, proves to be effective in enhancing the material properties. In this study, the LiNi0.8Co0.1Mn0.1O2 (NCM811) sample underwent a dry grinding process, followed by Y2O3 coating and subsequent sintering at varying temperatures. The microstructure, morphology, and electrochemical properties of the materials were meticulously examined, and the underlying mechanism of coating modification was meticulously explored. The outcomes demonstrate the attainment of dual coating and doping effects through Y2O3 modification. Y2O3 coating mitigates the direct interaction between the NCM811 surface and the electrolyte, thereby inhibiting undesired side reactions at the interface. Moreover, the Y element infiltrates the crystal structure, imparting stability at elevated sintering temperatures. Remarkably, the Y2O3-coated cathode materials exhibit significantly enhanced cycling stability, discharge capacity, and rate performance. These findings can provide novel insights that can be harnessed to improve the energy density cathode material of NCM811.

In-situ plasma assisted lithium-ion battery cathodes to catalytically pyrolyze lignin for H2-rich syngas production

In-situ plasma assisted lithium-ion battery cathodes catalysis was investigated to pyrolyze lignin to H2-rich syngas, oil and char. The effects of temperature, cathode to lignin ratio and plasma current on syngas production were investigated by using the typical ternary cathode NCM111 (LiNi1/3Co1/3Mn1/3O2) as catalyst and adopting dielectric barrier discharge mode. Response surface methodology based on BOX-BEHNKEN design was used to analyze the significance and interactions of process factors on the syngas yield. The conditions of 837℃, 10.4 %, and 185 mA for obtaining high-yield syngas (22.58 %) were more stringent; thereinto, from high to low, the intensity of factors on the yield was temperature, plasma current, and cathode ratio. Furthermore, different cathodes (non-cathode, NCM811 (LiNi4/5Co1/10Mn1/10O2), LCO (LiCoO2), and LMO (LiMn2O4)) were applied to decouple the catalytic effects of three metals in the NCM111. NCM111 enhanced both lignin gasification and carbonization by reducing condensable components, and NCM811 further improved gasification, but LCO and LMO had weaker gasification ability. NCM111 increased H2 volume fraction from 22.35 % to 67.31 %, NCM811 elevated the micro-discharge performance, promoting the hydrogasification reactions between energetic H species and char to produce more CH4, while LCO and LMO tended to produce the CO-rich syngas. Besides, in-situ plasma and its synergy with cathodes inhibited the formation of heavy aromatics and produced some high-value bio-oils rich in light aromatics, in which NCM111 achieved 92.30 % selectivity towards MAHs. High Ni ratio was beneficial for improving the char porosity, and the chars obtained by using NCM811 had a surface area of 409.29 m2/g, and a pore volume of 0.401 cm3/g. Comparably, the degree of catalytic lignin gasification for preparing H2-rich syngas could be ranked as Ni > Co > Mn in the ternary cathode.

Enhanced selective separation of valuable metals from spent lithium-ion batteries by aluminum synergistic sulfation roasting strategy

Recycling of spent lithium-ion batteries has become crucial due to the current situation of resource shortage and environmental pollution. Herein, the proposed process fully utilizes cheap ammonium sulfate as sulfating agent and aluminum foil of spent lithium-ion batteries itself as reducing agent for synergistically roasting the cathode material. Thermodynamic analysis and experimental results show that, different from conventional sulfation and thermite reduction roasting, aluminum synergistic sulfation roasting converts Li in the cathode material to water-soluble Li2SO4 instead of LiMn2O4 and LiAlO2, and reduces transition metals to acid-soluble low-valent oxides instead of high-valent oxides or metal elements. The effects of roasting temperature, ammonium sulfate dosage, and roasting time on the phase transformation were studied. Under the optimal roasting parameters (T = 600 °C, n[(NH4)2SO4]:n(2Li) = 1.4, t = 1.0 h) of spent ternary cathode, the water leaching efficiency of Li is 97.2 % with less than 0.5 % of Al and transition metals being co-leached. Subsequently, more than 96 % of Al and 99 % of transition metals can be extracted through alkaline and non-reducing agent acid leaching, respectively. This work provides a potential approach and valuable technical reference for the efficient and selective recovery of valuable metals directly from the spent ternary cathode with high aluminum content.

Identifying key determinants of discharge capacity in ternary cathode materials of lithium-ion batteries

Although lithium-ion batteries (LIBs) currently dominate a wide spectrum of energy storage applications, they face challenges such as fast cycle life decay and poor stability that hinder their further application. To address these limitations, element doping has emerged as a prevalent strategy to enhance the discharge capacity and extend the durability of Li-Ni-Co-Mn (LNCM) ternary compounds. This study utilized a machine learning-driven feature screening method to effectively pinpoint four key features crucially impacting the initial discharge capacity (IC) of Li-Ni-Co-Mn (LNCM) ternary cathode materials. These features were also proved highly predictive for the 50th cycle discharge capacity (EC). Additionally, the application of SHAP value analysis yielded an in-depth understanding of the interplay between these features and discharge performance. This insight offers valuable direction for future advancements in the development of LNCM cathode materials, effectively promoting this field toward greater efficiency and sustainability.

Physics-informed data-driven model of dehydration reaction stage in the sintering process of ternary cathode materials

The sintering process is the main process that affects the performance of ternary cathode materials. Due to the closed, continuous, and long-term characteristics of the sintering process carried out in a roller kiln, the reaction state including reaction degree, particle size, and etc., of the raw materials cannot be directly obtained through sampling detection, resulting in ineffective temperature control. This article mainly focuses on modeling the dehydration reaction stage of the sintering process to obtain the reaction state of the raw materials. Firstly, a two-sphere model is established based on Newton’s second law and the particle volume conservation equation to describe the relationship between the particle radius and sintering temperature of lithium hydroxide and ternary precursor; Secondly, the chemical kinetic parameters of the dehydration reaction in the two-sphere model are obtained by combining the single heating rate scanning method with the multiple heating rate scanning method; Then, in order to improve the accuracy of the two-sphere model and reduce the impact of external environmental temperature changes, a physics-informed neural network model is constructed by combining the two-sphere model with the neural ordinary differential equation model. Finally, the effectiveness of the modeling method is verified through numerical simulation and empirical data.

Bifunctional Treatment of Spent Ternary Cathode Materials with Improved Electrochemical Performance

Bifunctional Treatment of Spent Ternary Cathode Materials with Improved Electrochemical Performance

A large volume and low energy consumption recycling strategy for LiNi0.6Co0.2Mn0.2O2 from spent ternary lithium-ion batteries

The increased demand for energy storage devices has led to an explosive increase in spent lithium-ion batteries. However, traditional pyrometallurgy/hydrometallurgy recycling processes require high-temperature treatment, high-concentration acid leaching with reductant (H2O2), and a complex procedure, which exist energy and environmental issues. Herein, combining the advantages of pyrometallurgy and hydrometallurgy method, we proposed a new large-scale battery recycling strategy with industrial application prospects. In this strategy, lithium element is preferentially leached, and Ni0.6Co0.2Mn0.2(OH)2 and LiNi0.6Co0.2Mn0.2O2 is directly synthesized by coprecipitation and calcination process using the high-concentration transition metal leachate (∼1.0 M). So, the step separation of Li, Ni, Co, and Mn element is avoided, which makes the recycling procedure shorter than hydrometallurgy. Moreover, during the leaching process, low-concentration acid is used, and reductant (H2O2) are not required. By optimizing the experimental conditions, the recycling rate of Li, Ni, Co, and Mn is 94.47%, 99.36%, 99.28%, 99.56%. The regenerated LiNi0.6Co0.2Mn0.2O2 has comparable electrochemical properties to commercial LiNi0.6Co0.2Mn0.2O2 with 163 mAh g−1 capacity at 1C current density and 85.08 % capacity remains after 300 cycles. After calculation, the recycling strategy can obtain an economic benefit of 20,667 $ per ton of recycling spent ternary cathode powder. These results show that this method has spacious prospects for the battery recycling market, which can be further extended to industrial application for recycling spent ternary LIBs.

Photocatalytic oxidation degradability of ammonia–nitrogen and Ni/Co ammonia complexes in ternary precursor wastewater by constructing MoS2/g-C3N4 heterojunction: Performance and mechanism

In this study, MoS2/g-C3N4 heterojunction photocatalysts were fabricated in order to treat ammonia–nitrogen wastewater resulting from the production of ternary cathode material precursors used in the manufacture of lithium-ion batteries. The catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), N2 adsorption–desorption test, UV–Vis diffuse reflectance spectra (UV–Vis DRS), Fourier-transform infrared spectroscopy (FT-IR Nicolet 6700), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The catalytic efficiency of the catalysts on ammonia–nitrogen and Ni/Co ammonia complexes in the wastewater was investigated by varying MoS2 doping, catalyst dose, adsorption duration, and photocatalysis duration. The results showed 2.0 g/L of MoS2/g-C3N4-1 wt% (photocatalyst with a content of 1 wt% MoS2) has the best photocatalytic efficiency. A degradation efficiency of 87.52 % for ammonia–nitrogen, 98.34 % for nickel and 97.80 % for cobalt was reached after one hour of dark adsorption and four hours of illumination. EDS and XPS analysis revealed that Ni2+/Ni3+ and Co2+/Co3+ were adsorbed from the solution onto the catalyst surface, and that NH4+/NH3 was converted into NO3− and N2.

Recovery of metal ions in lithium iron phosphate powder and lithium nickel-cobalt-manganate powder by electrochemical oxidation

In recent years, lithium-ion batteries have been increasingly used in electric and hybrid vehicles. It is anticipated that the first lithium-ion batteries will be discarded at the height of their useful lives in 2025, so developing an effective and ecologically friendly recycling process is essential. In this study, an electrochemical cathode synergism is proposed for the electro-catalyzed oxidation of lithium nickel cobalt manganese oxide powder and lithium iron phosphate powder to extract metal. The oxidation of Fe2+ and the release of Li+ (98 %) in LiFePO4 and the leaching of Ni (92 %), Co (91 %), Mn (94 %) and Li (97 %) from its NCM523 were mainly triggered by the rapid attack of a large amount of OH during advanced oxidation. The leaching kinetic analysis showed that the leaching system for electrochemical leaching of binary and ternary cathode materials was a chemical reaction control model, and the leaching thermodynamic analysis showed that the dissolution of each metal ion was feasible in this leaching environment. The suggested recycling technique utilizes fewer chemicals and generates less waste when compared to previous recycling techniques. The method offers a fresh approach to environmentally friendly recycling for spent lithium-ion battery leaching and recycling.

Mg/Al Double-Pillared LiNiO2 as a Co-Free Ternary Cathode Material Ensuring Stable Cycling at 4.6 V.

Cobalt-free (Co-free) and nickel-rich (Ni-rich) cathode materials have attracted significant attention and undergone extensive studies due to their affordability and superior energy density. However, the commercialization of these Co-free materials is hindered by challenges such as cation disorder, irreversible phase changes, and inadequate high-voltage performance. To overcome these challenges, a Co-free ternary cathode material of Mg/Al double-pillared LiNiO2 (NMA) synthesized via a wet-coating and lithiation-sintering technique is proposed. Fundamental studies reveal that Mg and Al have the potential to form a distinctive double-pillar structure within the layered cathode, enhancing its structural stability. To be specific, the strategic placement of Mg and Al in Li and Ni layers, respectively, effectively reduces Li+/Ni2+ disorder and prevents irreversible phase transitions. Additionally, the inclusion of Mg and Al refines the primary grains and compacts the secondary grains in the cathode material, reducing stress from cyclic usage and preventing material cracking, thereby mitigating electrolyte erosion. As a result, NMA demonstrates exceptional electrochemical performance under a high charge cutoff voltage of 4.6 V. It maintains 70% of initial specific capacity after 500 cycles at 1 C and exhibits excellent rate performance, with a capacity of 162 mAh g-1 at 5 C and 149 mAh g-1 at 10 C. As a whole, the produced NMA achieves a high structural stability in cases of excessive delithiation, providing a groundbreaking solution for the development of cost-effective and high-energy-density cathode materials for lithium-ion batteries.

The accurate estimation of Li/Ni mixing degree of lithium nickel oxide cathode materials

Abstract Li/Ni mixing negatively influences the discharge capacity of lithium nickel oxide and high-nickel ternary cathode materials. However, accurately measuring the Li/Ni mixing degree is difficult due to the preferred orientation of lab-based XRD measurements using Bragg-Brentano geometry. Here, we find that employing spherical harmonics in Rietveld refinement to eliminate the preferred orientation can significantly decrease the measurement error of the Li/Ni mixing ratio. The Li/Ni mixing ratio obtained from Rietveld refinement with spherical harmonics shows a strong correlation with discharge capacity, which means the electrochemical capacity of lithium nickel oxide and high-nickel ternary cathode can be estimated by the Li/Ni mixing degree. Our findings provide a simple and accurate method to estimate the Li/Ni mixing degree, which is valuable to the structural analysis and screening of the synthesis conditions of lithium nickel oxide and high-nickel ternary cathode materials.

Insight into recycling spent power ternary cathode materials: Towards preparation of Mn-based catalyst for efficient toluene removal

Both the resource utilization of spent power ternary lithium-ion batteries (LIBs) and degradation of volatile organic compounds (VOCs) by thermal catalytic oxidation are environmental concerns. In this study, a novel perspective is presented: the Mn-based composite metal oxide catalysts were synthesized via impregnation of spent ternary cathode materials for the thermocatalytic oxidative degradation of toluene gas. The results demonstrated that the optimal conditions for catalyst synthesis were a 2% Mn loading, a Co/Mn molar ratio of 0.4, and calcination at 500 ℃ for 6 h. The effectiveness of catalysts is determined by two inherent factors: the specific surface area and the presence of active sites on the surface. The degradation of toluene remained stable across various reaction environments, with the predominant degradation mechanism being Marks-Van-Kreven (MVK) model. The toluene undergoes oxygenation on the catalyst in this pathway, resulting in the formation of H2O, CO2, and intermediates containing benzene rings; and simultaneously, the catalyst is regenerated. The present study offers a valuable reference for the resource utilization of spent ternary LIBs and advances the development of catalysts for efficient degradation of VOCs.

Numerical and experimental study on the calcination process of the raw materials of lithium battery cathode

Ternary cathode materials hold great promise in the lithium battery market, yet analyses regarding their calcination process in simulation and on-site experimentation, are few. In this paper, a multiphysics-coupled computational fluid dynamics (CFD) model was developed to simulate the primary calcination process (The actual production process is divided into two calcinations, because the production conditions affect the measurement, this paper focuses on the analysis of the primary calcination process) of lithium battery raw materials (namely, Ni0.8Co0.1Mn0.1(OH)2 and LiOH∙H2O mixture, hereinafter referred to as raw materials) under oxidizing atmosphere conditions. The process involves fluid flow, heat and mass transfer, and chemical reactions. A new method which combined steady-state calculation with transient calculation was adopted. Firstly, the steady-state simulation of the whole furnace was carried out, and then the transient simulation of each furnace area is carried out consequently, the heat and mass transfer processes of raw materials in different furnace zones were solved, ultimately achieving the simulation of the entire furnace calcination process. On-site black box experiments were performed to obtain the temperature evolution during the calcination process. Meanwhile, compared with the calculated results of the model, it was found that the average hit rate with an absolute error of less than ±20 °C above 300 °C can reach 86.9%, confirming the applicability of the model. The multiphysics-coupled CFD model simultaneously solves the oxygen concentration. The process parameters were analyzed based on the model, providing a fundamental method for the improvement of the performance of lithium battery cathode materials calcination process.

The Le Chatelier's principle enables closed loop regenerating ternary cathode materials for spent lithium-ion batteries

The surging number of spent lithium-ion batteries (LIBs) has created great challenges to the ecological environment and lithium resources, and how to achieve high-value recycling of spent LIBs is an effective route to address the current challenges. In this paper, based on Le Chatelier's principle, we propose a strategy for efficient and green closed-loop recycling and utilization of spent NCM523 without alkali solution using Le Chatelier's principle. Citric acid as leaching agent, and oxalic acid with larger pKa as precipitant is susceptible to release H+ in the carboxylic acid group and combine with citrate ion after adding to the leaching solution. The compound decomposition reaction occurs in the system to obtain oxalic acid precursor and citric acid simultaneously, realising the closed-loop utilisation of leaching solution recycling. The regeneration of LiNi0.5Mn0.3Co0.2O2 (NCM523) was successfully achieved by combining the salt solution precipitation and roasting processes, resulting in a leaching rate of more than 99 % for Li, Ni, Co and Mn. The restored NCM523 exhibits uniform particle size distribution and intact laminar structure, as well as good cycling stability and rate performance as cathode materials for LIBs. The strategy is more atom economy efficiency and enviro-friendly than traditional pyrometallurgical and hydrometallurgical recycling technologies, which enables green and efficient closed-loop recycling of spent LIBs. This work provides an efficient and economic solution for the recovery and regeneration of spent lithium-ion battery cathode materials.