Mixed Cathode Materials Research Articles

All-Cobalt-Free Layered/Olivine Mixed Cathode Material for High-Electrode Density and Enhanced Cycle-Life Performance

All-Cobalt-Free Layered/Olivine Mixed Cathode Material for High-Electrode Density and Enhanced Cycle-Life Performance

Sustainable upcycling of mixed spent cathodes to a high-voltage polyanionic cathode material

Sustainable battery recycling is essential for achieving resource conservation and alleviating environmental issues. Many open/closed-loop strategies for critical metal recycling or direct recovery aim at a single component, and the reuse of mixed cathode materials is a significant challenge. To address this barrier, here we propose an upcycling strategy for spent LiFePO4 and Mn-rich cathodes by structural design and transition metal replacement, for which uses a green deep eutectic solvent to regenerate a high-voltage polyanionic cathode material. This process ensures the complete recycling of all the elements in mixed cathodes and the deep eutectic solvent can be reused. The regenerated LiFe0.5Mn0.5PO4 has an increased mean voltage (3.68 V versus Li/Li+) and energy density (559 Wh kg–1) compared with a commercial LiFePO4 (3.38 V and 524 Wh kg–1). The proposed upcycling strategy can expand at a gram-grade scale and was also applicable for LiFe0.5Mn0.5PO4 recovery, thus achieving a closed-loop recycling between the mixed spent cathodes and the next generation cathode materials. Techno-economic analysis shows that this strategy has potentially high environmental and economic benefits, while providing a sustainable approach for the value-added utilization of waste battery materials.

Leaching Li from mixed cathode materials of spent lithium-ion batteries via carbon thermal reduction.

The use of a carbon thermal reduction roasting method to recover lithium resources from spent lithium-ion batteries (S-LIBs) provides an important opportunity for recycling S-LIBs. The preferential extraction of Li via reduction roasting has been widely studied; however, the extraction of Li from mixed cathode materials has been rarely reported. Herein, we propose a method based on carbon thermal reduction to preferentially extract Li from mixed cathode materials. It was confirmed that there are differences in carbon thermal reduction products at 700 °C-850 °C by the thermodynamic analysis of the carbon thermal reduction process. At the same time, the effects of factors such as roasting temperature, roasting time, and material ratio on Li leaching efficiency were investigated. The Li recovery rate reached 98.86% under the optimal conditions of holding at 750 °C for 4 h with a molar ratio of mixed cathode materials to graphite of 1 : 0.25. Recovered Li2CO3 can be directly used as a lithium source for the regeneration of cathode materials. This study will provide new opportunities for the efficient recycling of spent lithium-ion batteries (S-LIB) mixtures.

Nanoscale chemical imaging with structured X-ray illumination.

High-resolution imaging with compositional and chemical sensitivity is crucial for a wide range of scientific and engineering disciplines. Although synchrotron X-ray imaging through spectromicroscopy has been tremendously successful and broadly applied, it encounters challenges in achieving enhanced detection sensitivity, satisfactory spatial resolution, and high experimental throughput simultaneously. In this work, based on structured illumination, we develop a single-pixel X-ray imaging approach coupled with a generative image reconstruction model for mapping the compositional heterogeneity with nanoscale resolvability. This method integrates a full-field transmission X-ray microscope with an X-ray fluorescence detector and eliminates the need for nanoscale X-ray focusing and raster scanning. We experimentally demonstrate the effectiveness of our approach by imaging a battery sample composed of mixed cathode materials and successfully retrieving the compositional variations of the imaged cathode particles. Bridging the gap between structural and chemical characterizations using X-rays, this technique opens up vast opportunities in the fields of biology, environmental, and materials science, especially for radiation-sensitive samples.

Selective Extraction of Critical Metals from Spent Lithium-Ion Batteries.

Selective and highly efficient extraction technologies for the recovery of critical metals including lithium, nickel, cobalt, and manganese from spent lithium-ion battery (LIB) cathode materials are essential in driving circularity. The tailored deep eutectic solvent (DES) choline chloride-formic acid (ChCl-FA) demonstrated a high selectivity and efficiency in extracting critical metals from mixed cathode materials (LiFePO4:Li(NiCoMn)1/3O2 mass ratio of 1:1) under mild conditions (80 °C, 120 min) with a solid-liquid mass ratio of 1:200. The leaching performance of critical metals could be further enhanced by mechanochemical processing because of particle size reduction, grain refinement, and internal energy storage. Furthermore, mechanochemical reactions effectively inhibited undesirable leaching of nontarget elements (iron and phosphorus), thus promoting the selectivity and leaching efficiency of critical metals. This was achieved through the preoxidation of Fe and the enhanced stability of iron phosphate framework, which significantly increased the separation factor of critical metals to nontarget elements from 56.9 to 1475. The proposed combination of ChCl-FA extraction and the mechanochemical reaction can achieve a highly selective extraction of critical metals from multisource spent LIBs under mild conditions.

Recovery of Li, Mn, and Fe from LiFePO4/LiMn2O4 mixed waste lithium-ion battery cathode materials

The recovery of metals from the cathode material or used lithium-ion batteries is of both environmental and economic importance. In this study, stepwise precipitation by acid leaching was used to separate and recover lithium, iron, and manganese from the mixed LiFePO4/LiMn2O4 cathode material. The thermodynamic properties of the lithium, iron, and manganese metal phases, especially the stability range, were analyzed using Eh-pH diagrams. The leaching system with sulfuric acid and hydrogen peroxide released Fe3+, Mn2+, and Li+ ions from the cathode material. Fe3+ in the leaching solution was precipitated as Fe(OH)3 and finally recovered as Fe2O3 after calcination. Mn2+ in the leaching solution was recovered as MnCO3. The remaining Li+-rich solution was evaporated and crystallized into Li2CO3. The purity of the recycled MnCO3 and Li2CO3 met the standard of cathode materials for lithium-ion batteries. XRD and XPS analysis showed that the main phase in the leaching residue was FePO4. This process can be used to separate and recover metals from mixed waste lithium-ion battery cathode materials, and it also provides raw materials for the preparation of lithium-ion battery cathode materials.

A Minireview on the Regeneration of NCM Cathode Material Directly from Spent Lithium-Ion Batteries with Different Cathode Chemistries

Research on the regeneration of cathode materials of spent lithium-ion batteries for resource reclamation and environmental protection is attracting more and more attention today. However, the majority of studies on recycling lithium-ion batteries (LIBs) placed the emphasis only on recovering target metals, such as Co, Ni, and Li, from the cathode materials, or how to recycle spent LIBs by conventional means. Effective reclamation strategies (e.g., pyrometallurgical technologies, hydrometallurgy techniques, and biological strategies) have been used in research on recycling used LIBs. Nevertheless, none of the existing reviews of regenerating cathode materials from waste LIBs elucidated the strategies to regenerate lithium nickel manganese cobalt oxide (NCM or LiNixCoyMnzO2) cathode materials directly from spent LIBs containing other than NCM cathodes but, at the same time, frequently used commercial cathode materials such as LiCoO2 (LCO), LiFePO4 (LFP), LiMn2O4 (LMO), etc. or from spent mixed cathode materials. This review showcases the strategies and techniques for regenerating LiNixCoyMnzO2 cathode active materials directly from some commonly used and different types of mixed-cathode materials. The article summarizes the various technologies and processes of regenerating LiNixCoyMnzO2 cathode active materials directly from some individual cathode materials and the mixed-cathode scraps of spent LIBs without their preliminary separation. In the meantime, the economic benefits and diverse synthetic routes of regenerating LiNixCoyMnzO2 cathode materials reported in the literature are analyzed systematically. This minireview can lay guidance and a theoretical basis for restoring LiNixCoyMnzO2 cathode materials.

Separation of valuable metals from mixed cathode materials of spent lithium-ion batteries by single-stage extraction

Separation of valuable metals from mixed cathode materials of spent lithium-ion batteries by single-stage extraction

Катодный материал на основе LiNi1/3Mn1/3Co1/3O2 и активированного угля для гибридных накопителей энергии

The structure and specific electrochemical characteristics of a mixed cathode material based on ground LiNi1/3Mn1/3Co1/3O2 (NMC111) and highly porous activated carbon YEC-8B were studied. The mixed material containing 35 wt. % NMC111 and 65 wt. % YEC-8B (based on the mass of active materials), has a specific capacity ∼70% higher in comparison with the cathode material based on pure coal YEC-8B. It was shown that while cycling a lithium-ion supercapacitor with a cathode based on this mixed material at high current densities, no significant changes took place in the electrochemical characteristics of the material. It was demonstrated that this type of cathode material has two advantages: at low current densities it displays the charge-discharge properties of the cathode material of a lithium-ion battery with high specific energy, and at high current densities, it functions as a material of a supercapacitor with high specific power.

Creative Method for Efficiently Leaching Ni, Co, Mn, and Li in a Mixture of LiFePO4 and LiMO2 Using Only Fe(III)

Recycling end-of-life lithium-ion batteries has attracted widespread attention due to their potential environmental hazards and the importance of key metal supplies. However, the previously reported research methods are intended only for spent Ni–Co–Mn (NCM)-based lithium-ion batteries or spent lithium iron phosphate batteries. In this letter, a new method is proposed for recovering the mixed cathode materials of LiFePO4 and LiNi0.5Co0.2Mn0.3O2 from spent lithium-ion batteries by sole Fe2(SO4)3. According to our design, ferric iron itself acts as a Lewis acid and facilitates LiFePO4 to release the reducing agent of ferrous iron to reduce LiNi0.5Co0.2Mn0.3O2. Additionally, the environmentally friendly and efficient leaching process has been achieved for Ni, Co, Mn, and Li by reasonably adjusting the ratio of trivalent iron, LiFePO4, and LiNi0.5Co0.2Mn0.3O2. This method of processing mixed spent lithium-ion battery cathode materials significantly reduces the amount of reducing agent or oxidant usage. Also,it is effective at reducing time, energy consumption, and water consumption. It provides a new solution to recycling used lithium-ion batteries.

Recycling of mixed lithium-ion battery cathode materials with spent lead-acid battery electrolyte with the assistance of thermodynamic simulations

Based on the concept of recycling waste with waste, the mixed cathode materials of spent lithium-ion batteries were recycled with waste electrolyte from spent lead–acid batteries. With the assistance of thermodynamic simulations, the optimized recycling path of the mixed cathode materials was proposed and tested. A higher overall recycling ratio of valuable metals, that is, 94.9% of lithium, 94.5% of cobalt, 94.4% of nickel, and 95.5% of manganese, was achieved by replacing the oxalates/carbonates used in the precipitation process with sulfides and reducing the solubility of lithium carbonate in the lithium precipitation step at room temperature with ethanol. A higher ethanol-to-water ratio yielded a higher precipitation ratio of lithium until the ratio reached 5:1. High-purity lithium carbonate and cobalt (99.9%) were recovered as nanoparticles and nanoribbons, respectively, through precipitation using carbon dioxide in a solution with a 4:1 ethanol-to-water ratio and electrodeposition at E = −0.4 V in a traditional three-electrode system. Furthermore, the poisonous heavy metal (lead) was separated and stabilized as lead sulfide.

Recycling of mixed discarded lithium-ion batteries via microwave processing route

The ever increasing demand, the short life span of lithium-ion battery (LIBs), the presence of critical metals, and environmental considerations make recycling inevitable. A short duration, cost-effective recycling process for discarded mixed cathode material, and microwave reduction of cathode materials using recovered graphite are investigated. In this work, cathode materials of discarded LIBs are treated in the microwave for recovery of metallic values. Cathode and anode sheets of spent batteries were pulverized, sieved separately, and the active cathode material was reduced in the microwave at different times, graphite dosage, and microwave power. The microwave response of cathode material and reductants (graphite and charcoal) is investigated. A comparative analysis of microwave reduction of pure (LiCoO2) and mixed (LiCoO2, LiNi0.5Mn1.5O4, LiMn2O4) cathode materials was carried out using both graphite and activated charcoal. The final product comprises Co: 71.6%, Mn: 8.5%, Ni: 6.3%, O: 13.6% with saturation magnetization of 91 emu/g, lithium extraction: 82% and process yield of 32%. The indigenous microwave carbothermal reduction based process is found to be successful, considering product quality and cost considerations.

AC/Se composite cathode for asymmetric Li-ion capacitors

The asymmetric capacitors are one of the energy storage systems that provide high energy density and high power density. However, there are some limitations which impede the development of asymmetric capacitors. In this context, we designed a new type of lithium-selenium asymmetric capacitor (LSEC) that has both the capacitive effect and the diffusion-controlled reaction. The LSECs use the activated carbon-selenium (AC-Se) as a mixed cathode material and the pre-lithiated graphite as an anode material which can exhibit the electrochemical reduction/oxidation of Se and the adsorption/desorption of anions at substantially the same rate. This novel LSEC solves the problem of imbalance between the energy and the dynamics, and provides a solution to provide both high energy density and high power density, thus has great application potential.

Evaluation of carbothermic processing for mixed discarded lithium-ion batteries

The limited life span and huge demand for lithium-ion batteries, environment concerns, and the consumption of rare metals such as lithium and cobalt are the key facts for the worldwide recycling efforts. In this study, the cathode material of discarded lithium-ion batteries was carbothermally reduced using recovered graphite. A comparative evaluation of reduction behavior of single-phase (LiCoO2) and mixed-phase (LiCoO2.LiNi0.5Mn1.5O4.LiMn2O4) cathode materials was investigated under an ambient and inert atmosphere. Processing of single-phase cathode material in inert atmosphere yielded pure metallic cobalt, whereas, higher metallic recoveries and metal purity were obtained by processing of mixed cathode material in ambient conditions. The excellent product obtained under ambient conditions comprises 68% Co, 21% Mn, 2.5% Ni with saturation magnetization: 106 emu/g, and a precursor for the synthesis of cathode material. The process yield is 46.2% and lithium extraction 83%. In terms of metal purity and recovery, graphite was found to be better for reduction than activated charcoal. The process followed is simple, adaptable, and cost-effective for metals recovery from discarded lithium-ion batteries.

Synthesis of LiNi0.6Co0.2Mn0.2O2 from mixed cathode materials of spent lithium-ion batteries

With the aggravation of resource shortage and environmental problems, the disposal of spent lithium-ion batteries becomes crucial. In this work, a sustainable closed-loop route to recycle mixed cathode materials from spent lithium-ion batteries is proposed. The sulfuric acid and H2O2 were used to leach mixed cathode powders, and parameters such as temperature, acid concentration, and time were investigated. The leaching efficiency of each metal was observed to be above 99%. The ternary cathode precursor was directly prepared from leachate. Li2CO3 was recovered from the residual solution by adding saturated Na2CO3. The mixture of precursor and Li2CO3 was roasted to resynthesize ternary cathode materials (LiNi0.6Co0.2Mn0.2O2). The characterization of LiNi0.6Co0.2Mn0.2O2, as well as its electrochemical performance was investigated. LiNi0.6Co0.2Mn0.2O2 possesses a layered structure and shows excellent cycling stability and rate capacity. The capacities at the first charge and discharge at 0.2C are 196.26 mA h·g−1 and 180.072 mA h·g−1, respectively. The coulombic efficiency after the second cycle is observed to be about 99%.

A closed-loop process for recycling LiNixCoyMn(1−x−y)O2 from mixed cathode materials of lithium-ion batteries

With the rapid development of consumer electronics and electric vehicles (EV), a large number of spent lithium-ion batteries (LIBs) have been generated worldwide. Thus, effective recycling technologies to recapture a significant amount of valuable metals contained in spent LIBs are highly desirable to prevent the environmental pollution and resource depletion. In this work, a novel recycling technology to regenerate a LiNi1/3Co1/3Mn1/3O2 cathode material from spent LIBs with different cathode chemistries has been developed. By dismantling, crushing, leaching and impurity removing, the LiNi1/3Co1/3Mn1/3O2 (selected as an example of LiNixCoyMn(1−x−y)O2) powder can be directly prepared from the purified leaching solution via co-precipitation followed by solid-state synthesis. For comparison purposes, a fresh-synthesized sample with the same composition has also been prepared using the commercial raw materials via the same method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements have been carried out to characterize these samples. The electrochemical test result suggests that the re-synthesized sample delivers cycle performance and low rate capability which are comparable to those of the fresh-synthesized sample. This novel recycling technique can be of great value to the regeneration of a pure and marketable LiNixCoyMn(1−x−y)O2 cathode material with low secondary pollution.

A closed loop process for recycling spent lithium ion batteries

As lithium ion (Li-ion) batteries continue to increase their market share, recycling Li-ion batteries will become mandatory due to limited resources. We have previously demonstrated a new low temperature methodology to separate and synthesize cathode materials from mixed cathode materials. In this study we take used Li-ion batteries from a recycling source and recover active cathode materials, copper, steel, etc. To accomplish this the batteries are shredded and processed to separate the steel, copper and cathode materials; the cathode materials are then leached into solution; the concentrations of nickel, manganese and cobalt ions are adjusted so NixMnyCoz(OH)2 is precipitated. The precipitated product can then be reacted with lithium carbonate to form LiNixMnyCozO2. The results show that the developed recycling process is practical with high recovery efficiencies (∼90%), and 1 ton of Li-ion batteries has the potential to generate $5013 profit margin based on materials balance.

Synthesis and Characterization of Spinel-Layered Mixed Cathode Materials for Li-Ion Batteries From Ni-Mn Precursor in CSTR Reactor At Different Feeding Times

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A novel method to recycle mixed cathode materials for lithium ion batteries

The rechargeable lithium ion (Li-ion) battery market was $11.8 billion in 2011 and is expected to increase to $50 billion by 2020. With developments in consumer electronics as well as hybrid and electric vehicles, Li-ion batteries demand will continue to increase. However, Li-ion batteries are not widely recycled because currently it is not economically justifiable (in contrast, at present more than 97% lead-acid batteries are recycled). So far, no commercial methods are available to recycle Li-ion batteries with different cathode chemistries economically and efficiently. Considering our limited resources, environmental impact, and national security, Li-ion batteries must be recycled. A new low temperature methodology with high efficiency is proposed in order to recycle Li-ion batteries economically and thus commercially feasible regardless of cathode chemistry. The separation and synthesis of cathode materials (the most valuable material in Li-ion batteries) from the recycled components are the main focus of this study. The results show that the developed recycling process is practical with high recovery efficiencies, and that it is viable for commercial adoption.

Electrochemical Properties and Thermal Stability of LiNi0.8Co0.15 Al0.05O2-LiFePO4 Mixed Cathode Materials for Lithium Secondary Batteries

ABSTRACT: We prepared various LiNi 0.8 Co 0.15 Al 0.05 O 2 -LiFePO 4 mixed-cathode electrodes by changing the con-tent of LiNi 0.8 Co 0.15 Al 0.05 O 2 and LiFePO 4 used, and we analyzed the electrochemical characteristicsof the cathodes. We found that the reversible specific capacity of the cathodes increased and thatthe capacity retention ratios of the cathodes decreased during cycling as the content ofLiNi 0.8 Co 0.15 Al 0.05 O 2 increased. Conversely, we found that although the reversible specific capacityof the cathodes decreased because of the material composition, the cycle property of the cathodesincreased when the LiFePO 4 content increased. We analyzed the thermal stability of theLiNi 0.8 Co 0.15 Al 0.05 O 2 -LiFePO 4 mixed-material cathodes by differential scanning calorimetry andfound that it increased as the LiFePO 4 content increased.Keywords: LiNi 0.8 Co 0.15 Al 0.05 O 2 , LiFePO 4 , Thermal stability, Mixed-cathode, Cycle property Received May 8, 2012 : Accepted June 22, 2012