Lithium-ion Battery Cathode Research Articles

Superior conductive 1D and 2D network structured carbon-coated Ni-rich Li1.05Ni0.88Co0.08Mn0.04O2 as high-ion-diffusion cathodes for lithium-ion batteries.

Numerous studies have addressed the low electrical conductivity of Li1.05Ni0.88Co0.08Mn0.04O2 (Ni-rich NCM). Among these approaches, surface treatment using multiwalled carbon nanotubes (MWCNTs) has emerged as a promising strategy for enhancing the depolarization of Ni-rich NCM and improving its electrochemical performance. However, MWCNT coatings applied by various methods often result in agglomeration and increase the ion-transfer resistance of the coating layer, leading to degraded electrochemical performance. In this study, 1D and 2D network structures are assembled on Ni-rich NCM surfaces using a MWCNT solution dispersed in ethanol solvent by an incipient method. The resulting highly conductive network structure facilitates electron movement without interfering with Li-ion transport, enhancing the depolarization of Ni-rich NCM and enabling high electrochemical performance. The 1D and 2D network structure coated Ni-rich NCM exhibits an excellent rate capability of 87.64% at 3C/0.2C and a cycle retention of 94.53% after 50 cycles at 1C/1C. Moreover, the incipient method used herein effectively maximizes the electrochemical performance with less coating weight than other methods. These findings highlight the potential of the 1D and 2D network structure coated Ni-rich NCM for advanced energy storage applications.

Enhanced performance of lithium-ion battery cathodes using a composite conductive network of CNTs, GQDs, and GNRs embedded in Li₁.₂Mn₀.₅₄Ni₀.₁₃Co₀.₁₃O₂ (LMNCO)

Lithium-rich Li-ion battery cathode materials are known for their high specific capacities and working potential. However, their practical application is limited by the significant decline in discharge potential and capacity during repeated cycling. In this study, we introduce a highly conductive electrode architecture, encapsulating within carbon nanotubes (CNTs), graphene nano-ribbons (GNRs) and graphene quantum dots (GQDs) to mitigate rapid capacity fading and suppress voltage decay. Three Li1.2Mn0.54Ni0.13Co0.13O2 cathode materials were synthesized. The first sample, pristine Li-rich L1.2Mn0.54Ni0.13Co0.13O2, was synthesized using a nitrate co-precipitation method. The second cathode, GNRs-CNTs@Li1.2Mn0.54Ni0.13Co0.13O2, incorporates a mixture of carbon nanotubes and graphene nanoribbons. The third cathode, GQDs:GNRs-CNTs@Li1.2Mn0.54Ni0.13Co0.13O2), further integrates graphene quantum dots within the graphene nanoribbons and carbon nanotubes matrix. The inclusion of highly conductive GNRs-CNTs and GQDs effectively enhances the electrical conductivity of L1.2Mn0.54Ni0.13Co0.13O2, increasing the specific capacity from 246.95 to 316.94 mAhg−1. Additionally, GQDs prevent side reactions and surface phase transitions, thereby improving thermal stability.

A Conductive Cu-Based Metal-Organic Framework Ribbon with High-Density Redox-Active Centers as Cathode for Stable High-Capacity Lithium-Ion Batteries.

Conductive Cu-based metal-organic framework (Cu-MOF) materials hold significant potential as cathodes for lithium-ion batteries (LIBs) due to their flexible structural design, high electronic conductivity, and independence from costly resources. However, their practical application is often limited by their capacity and cyclability. In this study, we report a one-dimensional Cu-MOF (DDA-Cu, DDA=1, 5-Diamino-4, 8-dihydroxy-9, 10-anthraceneedione) featuring extended π-d conjugated coordination ribbon and high-density redox-active centers, making it a stable, high-capacity cathode for LIBs. The π-d conjugated Cu-O₃N motifs embedded within the ribbon not only serve as redox-active centers for enhanced lithium-ion storage capacity but also contribute to structural robustness, enabling resistance against electrode solubility in organic electrolytes, thus ensuring superior cyclability. Furthermore, these π-d conjugated Cu-O₃N units promote efficient charge transfer, leading to high electronic conductivity at room temperature. These advantageous properties allow the Cu-MOF cathode to deliver a remarkable capacity (353 mAh g-1 at 0.05 A g-1) and exceptional cyclability, achieving capacity retention of 78% after 1000 cycles, surpassing state-of-the-art MOF electrodes. Additionally, this DDA-Cu demonstrates considerable wettability with the electrolyte, achieving outstanding performance even when tested in a lean electrolyte environment (2 μL mg-1) with a high mass loading of the MOF (6.8 mg cm-2).

A Conductive Cu‐Based Metal‐Organic Framework Ribbon with High‐Density Redox‐Active Centers as Cathode for Stable High‐Capacity Lithium‐Ion Batteries

Conductive Cu‐based metal‐organic framework (Cu‐MOF) materials hold significant potential as cathodes for lithium‐ion batteries (LIBs) due to their flexible structural design, high electronic conductivity, and independence from costly resources. However, their practical application is often limited by their capacity and cyclability. In this study, we report a one‐dimensional Cu‐MOF (DDA‐Cu, DDA=1, 5‐Diamino‐4, 8‐dihydroxy‐9, 10‐anthraceneedione) featuring extended π‐d conjugated coordination ribbon and high‐density redox‐active centers, making it a stable, high‐capacity cathode for LIBs. The π‐d conjugated Cu‐O₃N motifs embedded within the ribbon not only serve as redox‐active centers for enhanced lithium‐ion storage capacity but also contribute to structural robustness, enabling resistance against electrode solubility in organic electrolytes, thus ensuring superior cyclability. Furthermore, these π‐d conjugated Cu‐O₃N units promote efficient charge transfer, leading to high electronic conductivity at room temperature. These advantageous properties allow the Cu‐MOF cathode to deliver a remarkable capacity (353 mAh g‐1 at 0.05 A g‐1) and exceptional cyclability, achieving capacity retention of 78% after 1000 cycles, surpassing state‐of‐the‐art MOF electrodes. Additionally, this DDA‐Cu demonstrates considerable wettability with the electrolyte, achieving outstanding performance even when tested in a lean electrolyte environment (2 μL mg‐1) with a high mass loading of the MOF (6.8 mg cm‐2)

Enhanced elevated-temperature performance of LiMn2O4 cathodes in lithium-ion batteries via a multifunctional electrolyte additive

LiMn2O4 is a promising cathode material for lithium-ion batteries (LIBs) due to its low cost, environmental friendliness, and high voltage operation. However, its electrochemical performance deteriorates at elevated temperatures, primarily by reason of the structural degradation during cycling and proliferation of adverse reactions at the electrode/electrolyte interface. One of the main reasons is that the hydrolysis and decomposition of the LiPF6 at high temperatures produces HF, which leads to corrosion at the electrode/electrolyte interface and accelerates manganese dissolution. In this work, we report a multifunctional silane-based electrolyte additive, trimethoxyphenylsilane (TMPS), to solve these problems. Theoretical calculations and experimental results both demonstrate that TMPS can eliminate HF, stabilize PF5, and inhibit LiPF6 hydrolysis, thereby mitigating transition metal leaching. Additionally, TMPS improves the stability between cathode and electrolyte by constructing a highly stable and homogeneous cathode-electrolyte interfacial. The LiMn2O4//Li cell using the electrolyte containing 1 wt% TMPS retains 95.5 % and 83.7 % of its capacity after 500 cycles at 25 °C and 60 °C, respectively. Moreover, 18650-type cylindrical cells with this electrolyte also exhibit enhanced electrochemical performance at elevated temperatures. It demonstrates that TMPS is a promising multifunctional additive for manganese-based cathodes in LIBs.

Enhancing the electrochemical performance of Ni-rich cathode through an in-situ La-doping and La4NiLiO8-coating synergistic strategy

Ni-rich layered oxides offer numerous advantages such as high discharge capacity, cost-effectiveness, and environmental friendliness, making them the mainstream cathodes for high-energy density lithium-ion batteries. However, their widespread commercialization is hindered by critical challenges in cycling performance, stemming from unstable interface and structure, particularly at elevated charge cut-off voltages. Herein, a dual-modification strategy combining La doping and La4NiLiO8 coating was proposed to synergistically enhance the surface/interface and structure stability of the LiNi0.83Co0.11Mn0.06O2 (referred to as NCM83) cathode. Unlike conventional methods, a well-designed La(OH)3 coating pretreatment was employed on the Ni0.83Co0.11Mn0.06(OH)2 precursor. This pretreatment aimed to facilitate the in-situ formation of La doping and La4NiLiO8 during the lithiation of the coated precursor, while ensuring desired uniformity of the La4NiLiO8 coating and La doping. This dual-modification strategy integrated the advantages of both La doping and La4NiLiO8 coating, demonstrating excellent capability to improve the overall performance of NCM83. The La doping, acting as a pillar, not only strengthened the layered structure of the cathode to mitigate volume changes, but also enhanced Li+ diffusion by broadening the c axis spacing. The La4NiLiO8 coating efficiently protected the cathode from H2O/CO2 attack and electrolyte erosion, while also facilitating Li+ transport owing to its favorable Li-conductive properties. Such a dual-modification strategy significantly enhanced the electrochemical performance of NCM83, as demonstrated by the excellent long-term cyclic stability, rate capability, and thermal stability at a high charge cut-off voltage of 4.5 V. This work highlighted the benefits of integrating elemental doping and surface coating, while offering a promising synthetic protocol for straightforward and effective dual-modification of various cathodes.

Fluorine-doped carbon coating of LiFe0.5Mn0.5PO4 enabling high-rate and long-lifespan cathode for lithium-ion batteries

The limited electron and ionic conductivity, along with the sluggish kinetics caused by the Jahn-Teller effect of Mn3+, impose constraints on the electrochemical performance of LiFexMn1-xPO4. Herein, the surface of LiFe0.5Mn0.5PO4 (LFMP) is modified with a F-doped carbon using the solvothermal and calcination methods. The incorporation of F-doped carbon coating, along with the formation of interfacial F-Li, F-Fe and F-Mn bonds between the carbon layer and LFMP nanoparticles, significantly mitigates charge transfer resistance, facilitates rapid electron transfer, as well as enhances Li+ diffusion kinetics. The LFMP@C-F2 cathode prepared in this study exhibits an unexceptionable capacity retention of 90.5 % after 300 cycles at a low rate of 0.2C and a capacity retention of 78.8 % over 1000 cycles at a high rate of 1C. When incorporated into the solid battery configuration (Li/PEO-LATP CSE/LFMP@C-F2), it exhibits an initial discharge specific capacity of 148 mAh g−1 and maintains a capacity retention of 85.8 % after 60 cycles at 0.1C, thereby offering an innovative approach to enhance the performance of LFMP in terms of cycling stability and rate capacity in lithium-ion batteries, as well as to apply LFMP into solid-state lithium batteries.

Selective Leaching for the Recycling of Lithium, Iron, and Phosphorous from Lithium-Ion Battery Cathodes’ Production Scraps

The market for lithium iron phosphate (LFP) batteries is projected to grow in the near future. However, recycling methods targeting LFP batteries, especially production scraps, are still underdeveloped. This study investigated the extraction of iron phosphate and lithium from LFP production scraps using selective leaching, considering technical and economic aspects. Two leaching agents, sulfuric acid (0.25–0.5 M, 25 °C, 1 h, 50 g/L) and citric acid (0.25–0.5 M, 25 °C, 1 h, 70 g/L) were compared; hydrogen peroxide (3–6%vv.) was added to prevent iron and phosphorous solubilization. Sulfuric acid leached up to 98% of Li and recovered up to 98% of Fe and P in the solid residues. Citric acid leached 18–26% of Li and recovered 98% of Fe and P. Totally, 28% of Li was precipitated for sulfuric acid process, while recovery with citric acid did not produce enough precipitate for a characterization. Sulfur is the main impurity present in the precipitates. The total operative costs associated with reagents and energy consumption of the sulfuric acid route were below 3.00 €/kg. In conclusion, selective leaching provided a viable and economic method to recycle LFP production scraps, and it is worth further research to optimize Lithium recovery.

Ambient-pressure relithiation of spent LiFePO4 using alkaline solutions enables direct regeneration of lithium-ion battery cathodes

Lithium iron phosphate (LiFePO4) is widely recognized for its cost-effectiveness in manufacturing and high safety during usage, making it a favored choice for electric vehicles and energy storage stations. Nevertheless, the development of efficient and low-cost recycling methods has emerged as an urgent priority due to the economic and environmental benefits associated with it. Here, the present study successfully demonstrates the ambient-pressure relithiation of lithium-deficient LiFePO4 particles in alkaline solutions. Specifically, the incorporation of reductive sodium nitrite with lower redox potential in the alkaline environment spontaneously repairs the compositional and structural defects, facilitating effective lithium-ion insertion back into the original site. Consequently, the short-term annealing step promotes the formation of more thermodynamically stable particles, resulting in enhanced cycling stability and rate capability comparable to that of the pristine materials. The regenerated LiFePO4 cathode exhibits improved electrochemical performance in terms of long-term cyclability, high-rate properties and reduced polarization (a high retention of 93 % after 1000 cycles at 5C). The findings of this study suggest the significant potential for utilizing various reductants in an alkaline environment to achieve ambient-pressure relithiation, thereby facilitating the recycling and remanufacturing of spent lithium-ion cathode materials.

Synergetic pyrolysis of lithium-ion battery cathodes with polyethylene terephthalate for efficient metal recovery and battery regeneration

Spent LiNixCoyMnzO2 (x + y + z = 1) and polyethylene terephthalate are major solid wastes due to the growing Li-ion battery market and widespread plastic usage. Here we propose a synergistic pyrolysis strategy to recover valuable metals by thermally treating LiNi1/3Co1/3Mn1/3O2 and polyethylene terephthalate. With polyethylene terephthalate assistance, LiNi1/3Co1/3Mn1/3O2 decomposes at 400 °C, and fully converts to Li2CO3, MnO, and Ni-Co alloy at 550 °C within 30 min, using a 1.0:0.3 mass ratio of LiNi1/3Co1/3Mn1/3O2 to polyethylene terephthalate. Furthermore, density functional theory calculations confirm the preference for O-Li bonding. Surface adsorption and free radical/gaseous reduction reactions explain the role of polyethylene terephthalate in promoting lattice destruction. The complete decomposition facilitates efficient post-treatment, achieving over 99% recovery of Li, Ni, Co, and Mn via water washing. Regenerated LiNi1/3Co1/3Mn1/3O2 was synthesized by using recovered Li- and transition metal-containing products as feedstocks. This study provided a chemical-free, energy-saving, and scalable recovery strategy while addressing polyethylene terephthalate waste minimization.

Surface Phase Engineering stabilizes cycling of zero-cobalt single-crystalline layered cathodes

The imperative of addressing cobalt scarcity and the pursuit of heightened energy density propels the exploration of cobalt-free, single-crystalline layered oxide cathodes for lithium-ion batteries (LIBs). Notwithstanding, such cathodes are confronted with rapid capacity degradation due to mechanical instability especially for pronounced crack propagation under high voltage. Herein, we present surface molybdenum-doped single-crystalline LiNi0.8Mn0.2O2 (Mo-NM82) cathode with excellent cycling stability. Our work reveals that the incorporation of Mo engenders surface reconstruction featuring antisite defects. This Mo enrichment layer not only significantly alleviates anisotropic strain during cycling thus substantially diminishing crack formation, but also serves as a protective layer that suppresses the dissolution of transition metal ions into the electrolyte. We found that the short-range disorder induced by surface Mo doping significantly enhances the structural stability of NM82 during the lithiation and delithiation processes. Consequently, the Mo-NM82 cathode exhibits an impressive 92.9 % capacity retention after 300 cycles at 2.8–4.5 V, demonstrating great potential for practical application. This investigation unveils surface modification as a critical determinant of the mechanical stability of cobalt-free single-crystalline cathodes, offering a promising avenue in the structural design of high-performance, cost-effective cathodes.

Embedment of Molybdenum Disulfide in Electrospun Fibers as an Integrated Cathode for Lithium-Ion Batteries

As an important component of LIBs, the electrode material plays a crucial role in determining the lithium (Li) storage performance in LIBs. In this study, MoS2 nano-flowers were synthesized using a one-pot hydrothermal method. The resulting MoS2 nano-flower, along with PAN, were used as raw materials for electrospinning. After annealing treatment, MoS2/(carbon nanofibers) CNFs nano-composites coated with carbon fibers were formed. The CNFs coating exhibited electrical conductivity and enhanced structural stability of the MoS2 due to the stabilizing effect of the carbon fibers. Additionally, electrochemical tests, including CV and GCD, indicated that the optimal capacity and cycling stability were achieved when the MoS2 content was 10%. The results indicated that the charge/discharge capacity of MoS2/CNFs-10% at a current density of 100 mA/g was ~650 mAh/g. After the cycling current returned to 100 mA/g, the current recovery was ~600 mAh/g, thereby indicating outstanding cycling stability. Accordingly, our fabrication technique and new insight could both widen design strategy of multicomponent composite electrode materials and promote the practical applications of the latest emerging transition metal sulfides in next-generation high-performance lithium-ion batteries.

Effect of La3+ Doping on the Electrical Properties of LiCoO2 Cathodes for Lithium-Ion Batteries

Effect of La3+ Doping on the Electrical Properties of LiCoO2 Cathodes for Lithium-Ion Batteries

Thermal stability of valuable metals in lithium-ion battery cathode materials: Temperature range 100–400 °C

Lithium is crucial in lithium-ion batteries (LIBs), serving as a main component of the electrolyte and cathode. Elements such as cobalt, nickel, and manganese are also vital for high performance, energy density, and stability. This study aimed to examine the behaviour of end-of-life cathode material (LiNi0.6Mn0.2Co0.2O2) and its valuable metals after exposure to temperatures between 100 and 400 °C, comparing it with untreated material. The lithium content cannot be reliably determined by conventional analytical methods, so inductively coupled plasma optical emission spectroscopy (ICP-OES) was chosen for this purpose. For ICP-OES measurements, samples were dissolved in different solvents for a specified time, and the concentrations of lithium, nickel, manganese, and cobalt were measured. From the measured values, their theoretical yields were calculated. Due to the annealing at given temperatures and subsequent dissolution, this step can be considered as the first stage of the pyrometallurgical-hydrometallurgical process used in battery recycling. The study was complemented by further analyses to monitor the effect of annealing temperatures on the properties of the material. Based on the results, it was found that the highest theoretical yield in this temperature range was for material annealed at 400 °C and dissolved in 20 % nitric acid for 4 h.

Research Progress of Lithium Iron Phosphate in the Cathode of Lithium-Ion Battery

Lithium-ion batteries (LIBs) have been a new candidate for various industries. Unlike other types of lead-acid batteries, LIBs have a very high energy density, power density, and nominal voltage, making them a beneficial choice of battery for many electronic devices like electric vehicles. The role of cathode material in the battery is to start the electrochemical reaction, and the rate capacity is highly dependent on the ion-diffusion rate at the cathode. This makes the cathode the most critical component in the battery. Therefore, it is essential to have excellent cathode material to perform its function. Lithium iron phosphate has always been a desirable cathode material due to its stable structure, high safety, and low cost. By choosing the appropriate material, high capacity and performance can be achieved. By modifying the material through different strategies, LFP has the potential to exceed its theoretical capacity and be applied in the broader field of the electronics industry. First, this article focuses on a comparison of different cathode materials and explains why LFP is superior. Then, it will introduce the synthesis methods, including solid-state, hydrothermal, and sol-gel methods. Finally, it will discuss ways to modify LFP, including nanostructured LFP, carbon coating, and doping. This paper aims to serve as a guide and reference for research in the battery industry.

Progress in the Application of LiMnPO4 Nanomaterials in Lithium-ion Battery Cathode

Lithium-ion batteries (LIBs) have become vital in today's energy storage systems, especially for electric cars and portable gadgets. High energy density, extended cycle life, and quick charging times are features of lithium batteries. Compared to conventional batteries, they are lightweight, ecologically benign, and have a low self-discharge rate. LiMnPO4 nanomaterials have garnered significant interest among various cathode materials due to their superior thermal stability, safety, and high operating voltage. The main topics of this paper are the structural characteristics, production techniques, and performance improvements of LiMnPO4 nanoparticles as LIBs cathodes. The basic operating principles of LIBs were covered in this article, with particular attention paid to the redox reactions occurring at the electrodes, the unique olivine structure of LiMnPO4, and how these factors affect electrochemical performance. The efficiency of many synthesis methods, such as spray pyrolysis, sol-gel, solid-state, hydrothermal, and solvothermal processes, in yielding superior LiMnPO4 nanoparticles is assessed. Additionally, surface modifications through ion doping and carbon coating are reviewed to highlight their roles in enhancing conductivity and stability. This article aims to provide ideas for developing high-performance LiMnPO4 cathode materials to affect LIBs' development positively. This article aims to provide ideas for developing high-performance LiMnPO4 cathode materials to influence LIBs' development positively.

Oxygen vacancies-enriched spent lithium-ion battery cathode materials loaded catalytic membrane for effective peracetic acid activation and organic pollutants degradation

Advanced oxidation processes combined with membrane filtration technique offer a promising approach for pollution mitigation and catalyst recovery. Herein, a waste ternary lithium-ion battery cathode material of LiNixCoyMnzO2 (LNCM) loaded polytetrafluoroethylene (PTFE) membrane was synthesized for peracetic acid (PAA) activation (LNCM-PTFE/PAA) and 2,4,6-trichlorophenol (TCP) degradation. Such a novel membrane, with a catalyst loading of 10 mg (0.796 mg/cm2) of LNCM achieved 96.4 % removal of TCP (2 mg/L) within 20 min in neutral pH. The redox cycles of surface metals (such as Co3+/Co2+, Ni3+/Ni2+, and Mn4+/Mn3+/Mn2+) in spent LNCM efficiently enhance charge transfer and mediated PAA activation. And intrinsic oxygen vacancies in LNCM facilitated PAA adsorption and its cleavage. The resulting carbon-centered radicals (R-C•, CH3C(O)OO•) and 1O2 are identified as the primary reactive species that collaboratively participate in TCP degradation. Quantitative structure-activity relationship analysis demonstrated a substantial reduction in product toxicity. The successful practical application of the LNCM-PTFE/PAA membrane was exemplified by treating chlorophenol industrial wastewater. This study presents a new LNCM-PTFE/PAA catalytic membrane for high-efficiency water treatment and a novel perspective for green utilization of waste LNCM.

Enhancing chemomechanical stability and high-rate performance of nickel-rich cathodes for lithium-ion batteries through three-in-one modification

Ni-rich cathode, recognized for high specific capacities and cost-effectiveness, are deemed promising candidates for high-energy Li-ion batteries. However, these cathodes display notable structural instability and experience severe strain propagation during rapid charging and extended cycling under high voltage, hindering their widespread commercialization. To tackle this chemo-mechanical instability without compromising energy and power density, we propose an efficient modification strategy involving hexavalent metal cation-induced three-in-one modification to reconstruct the nanoscale surface phase. This strategy includes uniform W-doping, integration of cation-mixed phases, and Li2WO4 nanolayers on the surface of Ni-rich cathode microspheres. W-doping strengthen the bond to oxygen, thereby enhancing structural stability and suppressing oxygen loss linked to a layered-to-rock salt phase transition during deep delithiation process. Additionally, establishing a cation-mixing domain with an optimal thickness on the cathode surface enhances Li⁺ diffusivity and alleviates particle structural degradation. Moreover, Li2WO4 nanolayers reduce electrolyte side reactions and act as a damping medium against cycling stresses. Importantly, detailed investigations into structural changes before and after modification at varying current rates were conducted to better comprehend the rate-dependent degradation mechanism. These findings yield valuable mechanistic insights into the high-rate utilization of a viable Ni-rich cathode, ensuring prolonged service life in electric vehicles.

Thermal characteristics of LiMnxFe1-xPO4 (x = 0, 0.6) cathode materials for safe lithium-ion batteries

Lithium-ion batteries have recently gained attention as energy storage devices due to their high energy densities and various applications. Layered Ni-Mn-Co-based cathode materials are widely used for their high energy density; however, their high cost necessitates the exploration of alternatives. Consequently, olivine-type LiMnxFe1-xPO4 materials are gaining popularity and are being increasingly adopted. While the synthesis methods and electrochemical properties of these materials have been extensively studied, thermal analyses remain limited. In this study, we investigated the thermal properties of olivine-type LiMnxFe1-xPO4 by combining thermal analysis, structural analysis, and computational calculations to evaluate the safety of lithium-ion batteries. Our results show that the formation energy of LiMn0.6Fe0.4PO4 is more stable than that of LiFePO4. As temperature increases, LiFePO4 decomposes at 350 °C, whereas LiMn0.6Fe0.4PO4 begins to decompose at 450 °C. The P-O bond plays a crucial role in the thermal stability of these materials; as the temperature rises, the thermal stability of the PO4 group diminishes, leading to structural decomposition. To enhance thermal stability, it is recommended to experiment with doping small amounts of various elements at the P site. This paper provides valuable insights for the design and development of thermally stable olivine-structured cathodes for lithium-ion batteries.

Green low-melting mixture solvents/ionic liquids-based carbon materials and lithium-ion batteries recycling leachate unexpectedly cause water pollution from dissolved organic matter

Low-melting mixture solvents (LoMMSs) and ionic liquids (ILs) are regarded as green solvents for the recovery of lithium-ion batteries (LIBs) cathode with high sustainability. Unexpectedly, we find for the first time that the release of LoMMSs- or ILs-based carbon materials and LIBs recycling leachate into water can lead to significant pollution from dissolved organic matter (DOM). Moreover, COD, NH4–N and total P concentration in river from Jingjinji Region is relatively high due to the high concentration of DOM. This work would provide us a hint that the application of so-called green LoMMSs and ILs in materials preparation and LIBs recovery should be treated with high caution in order to minimize DOM pollution for the rivers in Jingjinji Region.