Performance Of Cathode Materials Research Articles

Reactive crystallization regulation for synthesizing NCM811 precursor by different impellers

The spherical and dense precursors with a narrow particle size distribution are essential to achieve high electrochemical performance in cathode materials. Four newly designed impellers, including the punched-flow turbine (PFT), punched-flow disc turbine (PFDT), curved-inclined-blade disc turbine (CIBDT), and 6-folded-pitched turbine (FPT-6), are applied to prepare the precursors to investigate the interplay among the fluid flow state, precursors’ morphology and growth, and physicochemical properties of cathodes. The flow and mixing features of double impellers are predicted using computational fluid dynamics, indicating that the FPT-6 plays a crucial role in crystal nucleation while PFDT facilitates crystal growth. This concurrence can be corroborated by examining the performance of precursors synthesized using these four impellers. It is first found that the electrochemical performance is distinctly enhanced by utilizing different impellers to regulate the specified nucleation and growth stage. By increasing the nucleation rate with double impellers of FPT-6, the tap density and sphericity of the precursor and cathode materials are significantly improved. The discharge capacity of cooperative agitators (FPT-6+PT) is 2.1 times that of the only propeller turbine at a high current density (10C). The later growth stage is suitably regulated by FPT-6 or PFDT; properly extended reactive time can enhance the sphericity and electrochemical performance. The dual mixed-impeller (PT/CIBDT) combines intense mixing and shear ability, attaining a dense spheroid with a highly smooth surface. The cycle retention of this cathode is increased by 10.35% after 200 cycles at 1C compared to a commercial counterpart. A regulatory strategy for the reactive co-precipitation process to enhance precursor stability is proposed here. Furthermore, the optimal operation parameters derived from this strategy can be effectively applied to commercial cathode materials.

Glassy Oxides as Positive Electrode Materials for Sustainable and High Energy Density Li-Ion and Na-Ion Batteries: First Attempts to Establish Relationships between Glass Compositions, Physicochemical Characterizations and Electrochemical Properties with Machine Learning and Design of Experiments Approaches

Today, rechargeable lithium-ion batteries (LIBs) represent one of the best alternatives to reduce our dependency on fossil fuels. LIBs are using cathode materials based on polycrystalline oxides or polyanionic compounds [1]. However, their performances can be limited by their crystalline structure when other compounds suffer from metallic dissolution and irreversible phase changes during cycling [2]. To overcome these key shortcomings, implementing glasses or glass-ceramics as cathode materials is an interesting approach [3]. Glasses have a structure composed of more free volume, and, in the literature that is mainly concerning glasses containing Vanadium transition metal, the glasses can so accept a large amount of lithium [4] and easily accommodate structural changes upon lithium ions extraction/insertion [5]. Furthermore, glass production is a scalable process and can be commercially easier to implement than most of synthesis processes of conventional cathode materials.The main objective targeted is to develop high capacity positive electrodes (up to 300mAh/g) for Li-ion batteries based on glassy oxides without critical transition metals such as Cobalt and Vanadium. The ambitious target is to exceed 1000Wh/kg at the active material level and so enable energy densities of 300-350 Wh/kg at the Li-Ion cell level. Additionally, the electrochemical behavior of some alkali-free glass compositions will be evaluated in sodium-ion configuration. The major scientific objective is to correlate the most relevant physicochemical properties of glass with the corresponding electrochemical performances using machine learning approaches or design of experiment methodology. For a better understanding of involved processes, three oxides glass families are studied as promising cathode materials for sustainable and high energy density lithium batteries. These oxides are composed of: i) a glass network-forming element (Si, B, P) leading to the 3 different families, ii) a transition metal (Mn, Fe, ...) and optionally iii) an alkali (Li, Na).The influence of the nature of the transition metal and the polyanionic group corresponding to the network-forming element (PO4, BO3, SiO4) on the electrical properties of the as-prepared glasses measured at different temperatures will be presented mainly for the lithiated compounds. For microstructural characterization, several techniques were coupled such as X-Ray Diffraction (XRD), SEM-EDX, DTA/TGA, Raman, IR and UV-Vis spectroscopies, Electrochemical Impedance Spectroscopy (EIS) and chronoamperometry.Finally, the electrochemical properties in terms of specific capacity, redox potentials, first cycle capacity loss, coulombic and energetic efficiencies of these materials were investigated in coin-cells vs lithium (or sodium) metal electrode. To understand the electrochemical processes involved in these materials at room temperature, SEM-EDX, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Mossbauër Spectroscopy for iron based compounds were coupled and performed on the as-prepared glasses and on ex-situ (after cycling) materials at different electrochemical states of charge.All the generated data and measurements were analyzed by machine learning approach and tools and in some cases compared with a more classical Design of Experiments (DOE) approach. For instance, figure 1 illustrates the contour diagram of first discharge capacities in the mixture diagram of phosphate glasses based on 3 different transition metal oxides. The final goal is to establish more precisely the relationships between the different glassy oxides structures and their electrochemical performances. First results of this important work of elaboration, characterization and data analysis will be presented here. This new study will bring significant elements to optimize both the glass composition and its elaboration conditions to obtain high performance cathode materials without critical materials.[1] Nitta, N. et al., Li-ion battery materials: present and future. Materials Today 18, 252–264 (2015).[2] Tesfamhret, Y. et al., On the Manganese Dissolution Process from LiMn2O4 Cathode Materials. ChemElectroChem 8, 1516–1523 (2021).[3] K. Kercher et al., « Mixed polyanion glass cathodes: Glass-state conversion reactions », J. Electrochem. Soc., vol. 163, no 2, p. A131-A137, 2016, doi: 10.1149/2.0381602jes [4] Afyon, S. et al., New High Capacity Cathode Materials for Rechargeable Li-ion Batteries. Scientific Reports 4, 7113 (2015).[5] Kindle, M. et al., Alternatives to Cobalt. ACS Sustainable Chemistry Engineering 9, 629–638 (2021). Figure 1

Prussian Blue Nanoplates for Potassium Ion Battery Cathode with High Capacity and High Energy Density

AbstractPrussian blue analogues (PBAs) represent as a class of materials with an open framework structure and have been intensively explored as the potential active materials for alkaline‐ion batteries. Here, we present the synthesis of Prussian blue nanoplates designed for use as high performance cathode materials in potassium‐ion batteries. Prussian blue nanoplates were synthesized through a facile solution precipitation route using a highly concentrated potassium citrate solution. The potassium‐rich environment during the synthesis facilitated horizontal growth of the crystals, yielding potassium‐rich Prussian blue nanoplates. The resultant Prussian blue nanoplates exhibited a significantly larger particle size of 600 nm and a reduced specific surface area of 6.8 m2 g−1, compared to conventionally synthesized Prussian blue hexahedrons. Half‐cell tests demonstrated that the Prussian blue nanoplates exhibited a high gravimetric capacity of 152.5 mAh g−1 with a nominal voltage 3.952 V at a C‐rate of 0.1 C, yielding an energy density of 602.7 Wh kg−1. Cycling tests demonstrated high cycling stability of the material, maintaining a capacity of 122.7 mAh g−1 and a nominal voltage of 3.923 V after 200 cycles at 0.2 C. In a full‐cell configuration with graphite anodes, a gravimetric capacity changed from 134.1 mAh g−1 to 108.9 mAh g−1 after 100 cycles at 0.2 C, demonstrating a good cycling stability. This work provides a new insight into the electrochemical properties of Prussian blue nanoplates and highlights their potential as high‐performance cathode materials for potassium‐ion batteries.

Polyoxovanadate Li7[V15O36(CO3)] and its derivative γ-LiV2O5 as superior performance cathode materials for aqueous zinc-ion batteries

Recently, many reports have been published about polyoxovanadates (POVs) with multiple electrons redox activity for energy storage. However, they are easily transformed into solid-state oxides after calcination. We noted that although dehydrated Li7[V15O36(CO3)] (Li7V15) exhibited a high capacity for lithium-ion batteries (LIBs), it was reported that the electrochemical behavior of the dehydrated sample same as γ-LiV2O5 (γ-LVO) which prepared by annealing the cluster and undehydrated Li7V15 was not redox-active. Interestingly, we were surprised to find that undehydrated Li7V15 and its derivative γ-LVO showed better electrochemical performance than LIBs when first proposed as the cathode to store Zn2+. Both Li7V15 and γ-LVO electrodes provided excellent rate performance and satisfied cyclability (135.0 and 214.1 mAh g−1 at 3 A g−1 after 1000 cycles, respectively). The fast kinetics of Li7V15 and γ-LVO were verified by pseudocapacitive analysis, GITT and EIS tests. Moreover, the Zn2+ storage mechanism and redox behavior of Li7V15 and γ-LVO were examined by ex-situ measurements. First-principles calculations revealed that the Zn2+ was chemisorbed on the clusters and physisorbed between the clusters. This work enriches the POVs cathode chemistry in aqueous energy storage.

Slug-flow synthesis of NCMA: Effect of substitution of cobalt with aluminum on the electrochemical performance of Ni-rich cathode for lithium-ion battery

Nickle-rich Li[Ni1-x-yCoxMny]O2 (x, y ≤ 0.1) (NCM) layered materials are known as promising cathode materials for next-generation lithium-ion batteries and electric vehicles owing to their high-reversible capacity and operating voltage of up to 3.6 vs Li/Li+. However, issues, such as irreversible phase transition, cation mixing, microcrack formation, thermal and structural stability of the material prevent its widespread adoption. Although, cation doping is a well-known technique to enhance the electrochemical performance of the NCM-based cathode material, the performance of the material is very sensitive to the doping amount. In this study, three Al-doped quaternary Ni-rich cathode materials Li[Ni0.85Co(0.1-x)Mn0.05Alx]O2 (where, x = 0–0.04) (NCMA) are synthesized through three-phase slug-flow based continuous manufacturing process followed by high temperature calcination to study the effect of Al-doping on the performance of the cathode material while reducing Co. The slug flow-based production platform has several advantages, like particle size uniformity, high production rate, and homogeneity in elemental distribution. It is found that with an increase in Al content, the specific capacity decreases but the cyclic stability and rate capability increases. Optimum Al-doping not only compensates for the adverse effect of low Co by decreasing the extent of cation mixing, but it also minimizes the electrode polarization and cracking of the particles.

Methyl-Symmetrically Substituted Poly(3,4-Dimethylthiophene) as Cathode for Aluminum Ion Batteries.

The aggravation of energy problems and the scarcity of lithium resources have forced us to look for new energy storage systems. Aluminum ion batteries, as a promising energy storage system, have the advantages of environmental friendliness and abundant aluminum resources, and have the potential for application in large-scale energy storage and personal portable electronic devices. To solve the stability problem of aluminum ion batteries during cycling for large-scale energy storage needs, we report a polythiophene-based conductive polymer, poly(3,4-dimethylthiophene) (PDMT), as a high performance cathode material for aluminum ion batteries. By introducing two methyl groups on the thiophene ring, we successfully adjust the local charge density of the heterocyclic thiophene, thus changing the electron delocalization characteristics, and improving the electrochemical reaction activity of the polythiophene (PTH) material as a redox electrode material. This also maintains the symmetry and regularity of the polymer structure, giving the material better cycling stability. The discharge specific capacity reaches 110 mAh g-1 at a current density of 200 mA g-1, far exceeding conventional PTH cathodes (~70 mAh g-1), and the capacity retention rate is 92.7 % after 1000 cycles. It also shows excellent rate performance due to the flexible structure of the conductive polymer.

Doping-Induced Surface and Grain Boundary Effects in Ni-Rich Layered Cathode Materials.

In this work, the effects of dopant size and oxidation state on the structure and electrochemical performance of LiNi0.8Co0.1Mn0.1O2 (NCM811) are investigated. It is shown that doping with boron (B) which has a small ionic radius and an oxidation state of 3+, leads to the formation of a boron oxide-containing surface coating (probably Li3BO3), mainly on the outer surface of the secondary particles. Due to this effect, boron only slightly affects the size of the primary particle and the initial capacity, but significantly improves the capacity retention. On the other hand, the dopant ruthenium (Ru) with a larger ionic radius and a higher oxidation state of 5+ can be stabilized within the secondary particles and does not experience a segregation to the outer agglomerate surface. However, the Ru dopant preferentially occupies incoherent grain boundary sites, resulting in smaller primary particle size and initial capacity than for the B-doped and pristine NCM811. This work demonstrates that a small percentage of dopant (2mol%) cannot significantly affect bulk properties, but it can strongly influence the surface and/or grain boundary properties of microstructure and thus the overall performance of cathode materials.

Asymmetric 1, 2-naphthoquinone cathode material with enhanced capacity for rechargeable aluminium ion batteries

Rechargeable aluminium ion batteries (RAIBs) offer higher safety and lower costs than traditional lithium-ion batteries and have therefore been seen in recent years as a very promising potential development in areas such as large-scale energy storage. However, the development of RAIBs is limited by the cathode material, with most research currently focused on inorganic materials. Organic small molecules like naphthoquinone (NQ) based derivants have the potential to be advantageous in designing high performance cathode materials due to their molecular structural diversity and tunability. Together with 1, 4-NQ, 1, 2-NQ was successfully prepared by chemical oxidation using naphthol derivatives and assembled as RAIBs. Elucidated by Gaussian calculation, the asymmetric structure of 1, 2-NQ provides reaction sites with a higher possibility of binding to AlCl2+ ions than 1, 4-NQ, to the extent that there is an expected enhancement in its electrochemical performance. It is verified by the experimental results that the chemical and electrochemical stability of NQ cathode materials in ionic liquids is improved by the asymmetric structure. The 1, 2-NQ based RAIBs exhibits an outstanding initial specific capacity of 165.9 mAh g−1 and remains at 117.2 mAh g−1 with a Coulombic efficiency of about 98 % after the cycling of 600 and longer cycle life than the 1, 4-NQ based ones. The working concept and satisfying performance of the NQ based cathode material suggest that asymmetric molecules could be a promising design strategy for developing high-performance electrode materials for RAIBs.

A Dual Active Site Organic–Inorganic Poly(O‐Phenylenediamine)/NH4V3O8 Composite Cathode Material for Aqueous Zinc‐Ion Batteries

AbstractAqueous zinc‐ion batteries, considered one of the important candidate technologies for green and environmentally friendly large‐scale energy storage, hinge upon the performance of cathode materials as the key factor driving their development. Vanadate oxide is a promising cathode material due to its high theoretical capacity; furthermore, in order to accelerate the reaction kinetics, ion or molecular intercalation is often utilized. However, non‐electrochemically active intercalants tend to cause capacity degradation. In this study, a one‐step hydrothermal method is employed to intercalate electrochemically active poly‐o‐phenylenediamine (PoPDA) into the interlayers of NH4V3O8 (NVO), with graphene oxide (GO) being used to further improve the conductivity of the composite material (NVO/PoPDA@GO). The insertion of PoPDA expands the interlayer spacing of the NVO, alters the charge distribution, and enhances the migration rate of Zn2+ among the hybrid materials. Additionally, PoPDA serves as a support within the interlayers, improving the material stability. Moreover, the reversible transformation and rearrangement of chemical bonds (C═N/C─N) in PoPDA allows for coordination with Zn2+, providing additional capacity. As a result, NVO/PoPDA@GO exhibits excellent electrochemical performance, releasing a specific capacity of 433 mAh g−1 at 0.5 A g−1, even with a capacity of 224 mAh g−1 at 5 A g−1. This work provides a promising direction for the preparation of organic–inorganic composite cathode materials with dual active components.

Layered BaV6O16·3H2O@GO as a high performance cathode material for calcium ion batteries.

The lack of suitable cathode materials has hampered the further development of calcium-ion batteries (CIBs). A novel composite cathode material, namely BaV6O16·3H2O@GO, was fabricated, which delivers a high specific capacity of 285.72 mA h g-1 at 50 mA g-1 after 50 cycles and a long cycle life, benefiting from a large layer spacing and robust structure. This study provides guidance for the development of vanadium-based cathode materials for CIBs.

Controllable hollow cube Cu7S4 cathode for aqueous zinc-ion batteries application

Hollow structure materials are considered as a promising candidates for energy storage and conversion systems. In this paper, hollow cube shape Cu7S4 nanomaterial was creatively constructed by a simple template method, which was used as high performance cathode material of zinc ion batteries, firstly. The results indicate that the discharge specific up to 335 mAh g−1 at the current density of 0.1 A g−1, which is higher than other materials. Moreover, the prepared Cu7S4 material has super-stable cyclic stability, with a capacity of about 320 mAh g−1 after 100 reversible cycles. The unique hollow cube structure increases the active contact area, reduces the transmission path, and improves the electrochemical performance. The design and synthesis strategies of electrode materials can provide a valuable reference significance for other electrode materials in energy storage applications.

Dynamic Electrochemical Action of Low Temperature Plasma Exposed NaFePO4/Activated BCC Nanocomposites in Cathode Applications

Abstract In this research, we designed a high performance cathode materials for sodium-ion batteries derived from cold plasma exposed NaFePO4/activated bamboo charcoal (BCC). XRD, FTIR, FESEM, and Brunauer–Emmett–Teller (BET) were used to examine the crystal structure, functional groups, morphological features, and surface area of the composites. The material's surface characteristics, such as wettability, adhesion, and conductivity analysis, were proved, and the energy storage capacity of the material and these characteristics were magnified by exposure to DC glow discharge plasma. In this work, the NaFePO4/activated BCC was subjected to DC glow discharge plasma with various plasma producing gases. The electrochemical investigation shows that the air plasma-treated composite produces the best results when compared to the untreated sample. The enhancement of the diffusivity of the composite reveals that the plasma-treated materials are appropriate for energy storage devices.

Stable multi-electron reaction stimulated by W doping VS4 for enhancing magnesium storage performance

Rechargeable magnesium batteries (RMBs) hold promise for offering higher volumetric energy density and safety features, attracting increasing research interest as the next post lithium-ion batteries. Developing high performance cathode material by inducing multi-electron reaction process as well as maintaining structural stability is the key to the development and application of RMBs. Herein, multi-electron reaction occurred in VS4 by simple W doping strategy. W doping induces valence of partial V as V2+ and V3+ in VS4 structure, and then stimulates electrochemical reaction involving multi-electrons in 0.5% W-V-S. The flower-like microsphere morphology as well as rich S vacancies is also modulated by W doping to neutralize structure change in such multi-electron reaction process. The fabricated 0.5% W-V-S delivers higher specific capacity (149.3 mA h g−1 at 50 mA g−1, which is 1.6 times higher than that of VS4), superior rate capability (76 mA h g−1 at 1000 mA g−1), and stable cycling performance (1500 cycles with capacity retention ratio of 93.8%). Besides that, pesudocapaticance-like contribution analysis as well as galvanostatic intermittent titration technique (GITT) further confirms the enhanced Mg2+ storage kinetics during such multi-electron involved electrochemical reaction process. Such discovery provides new insights into the designing of multi-electron reaction process in cathode as well as neutralizing structural change during such reaction for realizing superior electrochemical performance in energy storage devices.

Hierarchical amorphous vanadium oxide and carbon nanotubes microspheres with strong interface interaction for Superior performance aqueous Zinc-ion batteries

Aqueous zinc-ion batteries have attracted more and more attention due to their safety, environmental benignity and high theoretical capacity. However, the lack of appropriate cathode materials with high capacity and long cycle life have become an obstacle to the development of aqueous zinc-ion batteries. Herein, the hierarchical amorphous vanadium oxide and carbon nanotubes (a-V2O5@CNTs) microspheres with strong interface interaction were successfully prepared by combing facile spray drying technique with annealing treatment. Benefiting from the a-V2O5 amorphous characters, CNTs framework high conductivity and hierarchical microspheres with strong interface interaction, the a-V2O5@CNTs exhibited abundant active sites, fast reaction kinetics as well as eminent structure stability. As a promising electrode material, the a-V2O5@CNTs displayed high specific capacity (480 mAh g−1 at 0.5 A g−1), good rate capability and long-term stability under high current density (158 mAh g−1 at 30 A g−1 over 1000 cycles). Meanwhile, the corresponding mechanism was further illustrated through different characterizations. Furthermore, the as-assembled flexible pouch battery based on the a-V2O5@CNTs delivered outstanding flexibility and feasibility. Hence, this work provides a new idea for developing high performance cathode materials of aqueous zinc-ion batteries.

Sustainable cathode material selection in lithium-ion batteries using a novel hybrid multi-criteria decision-making

Nowadays, energy supply chains have been entangled with many factors (e.g., overconsumption, depletion of fossil fuels, and contamination of natural resources). Besides, many efforts have been made to discern different sources of renewable energy (e.g., photovoltaic solar energy, biomass energy, and various metals for energy storage). Among the metals, lithium has been more used in different industries, particularly the lithium-ion batteries (LIBs), due to their very high reactivity and lightweight. LIBs are energy storage systems containing an electrolyte, anode, cathode, current collector, and separator. The cathode is characterized as the most significant part of LIBs since it has a significant impact on the main features of the battery (e.g., power, energy density, and lifetime). In this study, the evaluation of cathode materials is investigated based on a set of economic, environmental, and tactical criteria in three main phases. In the first phase, a hybrid multi-criteria decision-making (MCDM) based on subjective, objective, and combined weights including SAW-AHP, SAW-CILOS, SAW-AHP-CILOS, TOPSIS-AHP, TOPSIS-CILOS, TOPSIS-AHP-CILOS, CoCoSo-AHP, CoCoSo-CILOS, CoCoSo-AHP-CILOS, MARCOS-AHP, MARCOS-CILOS, and MARCOS-AHP-CILOS methods is developed and the performance of cathode materials is evaluated based on the final ranking of alternatives (FRA) and Copeland methodologies. In the second phase, using the efficient and anti-efficient frontiers determined by the data envelopment analysis (DEA) model, the performance of cathode materials is evaluated. In the third phase, the performance of the three proposed methodologies is compared. The results of this study demonstrate that the hybrid MCDM-FRA methodology is more flexible than the modified DEA model and hybrid MCDM-Copeland method to address the sustainable cathode material selection problem.

Fluorine Anion-Doped Ba0.6Sr0.4Co0.7Fe0.2Nb0.1O3-δ as a Promising Cathode for Protonic Ceramic Fuel Cells

The widespread application of protonic ceramic fuel cells is limited by the lack of oxygen electrodes with excellent activity and stability. Herein, the strategy of halogen doping in a Ba0.6Sr0.4Co0.7Fe0.2Nb0.1O3-δ (BSCFN) cathode is discussed in detail for improving cathode activity. Ba0.6Sr0.4Co0.7Fe0.2Nb0.1O3-x-δFx (x = 0, 0.05, 0.1) cathode materials are synthesised by a solid-phase method. The XRD results show that fluorine anion-doped BSCFN forms a single-phase perovskite structure. XPS and titration results reveal that fluorine ion doping increases active oxygen and surface adsorbed oxygen. It also confines chemical bonds between cations and anions, which enhances the cathode’s catalytic performance. Therefore, an anode-supported single cell with the configuration of Ni-BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb)|BZCYYb|Ba0.6Sr0.4Co0.7Fe0.2Nb0.1O3-0.1-δF0.1 (BSCFN-F0.1) achieved a high peak power density of 630 mW cm−2 at 600 °C. Moreover, according to the symmetrical cell test, the BSCFN-F0.1 electrode demonstrated a superb stability for nearly 400 h at 600 °C. This work focuses on the influence of fluorine anion incorporation upon the performance of cathode materials. It also analyses and discusses the effects of different fluorine ion incorporation amounts to occupy different oxygen positions.

High performance cathode materials for lithium-ion batteries based on a phenothiazine-based covalent triazine framework

A novel phenothiazine-based covalent triazine material (MPT-CTF) was successfully achieved from phenothiazine as a sustainable superior organic cathode material for lithium-ion batteries.

Cathode Choices for Rechargeable Aluminium Batteries: The Past Decade and Future

Rechargeable aluminium batteries are a promising alternative battery technology compared to lithium-ion batteries, because of the high theoretical capacity, low cost and high safety of aluminium. The past decade has witnessed the rapid development of rechargeable aluminium battery technology with the focus on exploring high performance cathode materials and investigating their charge storage mechanisms. However, the challenges in the cathode research including inadequate capacity, sluggish reaction kinetics and inferior cycling stability still remain. Various strategies have been attempted to address these challenges to realize the advantages of rechargeable aluminium batteries. The present review aims to collect the comprehensive body of research performed in the literature hitherto to develop interaction/conversion/coordination type cathodes for rechargeable aluminium batteries. Future research directions and prospects in rechargeable aluminium battery field are also proposed.

Experimental study on catalytic pyrolysis of rape straw with the active cathode material of spent lithium-ion batteries and HZSM-5 as the tandem catalysts

Effect of calcination temperature on the chemical composition, porous structure of cathode materials of spent lithium batteries (lithium iron phosphate, LFP; lithium nickel-cobalt manganate, NCM), and the production of high value-added products in the catalytic pyrolysis of rape straw with active cathode materials and HZSM-5 as the tandem catalysts were studied. The X-ray difraction and N2 adsorption-desorption analysis revealed that Fe2O3 and Co1.29Ni1.71O4 were mainly included in the LFP and NCM cathode materials calcined at 600 °C (LFP600 and NCM600), and the BET surface area of LFP600 and NCM600 reached the highest of 11.41 m2/g and 24.10 m2/g. In terms of catalytic performance, both LFP600 and NCM600 cathode materials showed best bond-breaking effect. Comparing these two cathode materials, LFP600 exhibited the better bond-breaking effect, while NCM600 presented a good deoxygenation effect. Finally, the synergistic effect of active cathode material and HZSM-5 was studied, and the quantitative yield of benzene, toluene and xylene reached 11.41 wt% and 10.96 wt% with the optimized calcined cathode material and HZSM-5 mass ratio of 1:5. In this study, it provides a new way to make high-valued utilization of solid wastes like agricultural and forest residues and spent lithium battery to produce clean and renewable energy.

Surface modification single crystal Li-rich Li1.2Mn0.54Ni0.13Co0.13O2 as high performance cathode materials for Li-ion batteries

To improve electrochemical performance and structure stability, Li3PO4 surface modification and single crystallization are applied for Li1.2Mn0.54Ni0.13Co0.13O2 to improve structural stability and upgrade electrochemical performance. The electrochemical characterization indicates that single crystal cathode material with Li3PO4 surface modification has high cycle stability and superior Li+ diffusion coefficient. Li-ion conductor Li3PO4 can supply diffusion channels for Li+ migration and inhibit phase transition. Coating Li3PO4 on Li-rich cathode materials is an effective method to improve the electrochemical performance and structure stability of the materials.