Cathode Material Research Articles

Synthesis and electrochemical studies of NaCoPO4 as an efficient cathode material using natural deep eutectic solvents for aqueous rechargeable sodium-ion batteries

Synthesis and electrochemical studies of NaCoPO4 as an efficient cathode material using natural deep eutectic solvents for aqueous rechargeable sodium-ion batteries

A new Co‐based cathode with high performance for intermediate‐temperature solid oxide fuel cells

AbstractSolid oxide fuel cells (SOFCs) as highly effective energy conversation devices have gained substantial recognition and research interest. The electrochemical properties of the traditional SOFCs are restricted by the sluggish reaction kinetics for the cathode material when lowering the operation temperature to below 600°C. In addition, the stability of the cathode at reduced temperatures is also a big challenge for the widely popularization of SOFC technology. Achieving high activities and stable ORR in the cathode is crucial for the development of SOFCs. The doping active metal method has been demonstrated as an effective approach to optimize the phase structure and improve the ORR activity of the cathode. Herein, we successfully develop an Ir‐doped SrCoO3 − δ (SrCo0.98Ir0.02O3 − δ, SCI) cathode for SOFCs. SCI exhibits a low area‐specific resistance (ASR) of 0.057 Ω cm2 at 650°C, ~ 44% lower than 0.102 Ω cm2 of Ir‐free SrCoO3 − δ. The Ni–Sm0.2Ce0.8O1.90 (SDC) anode‐supported fuel cell with SDC electrolyte and SCI cathode obtains an excellent output performance (e.g., 1,128 mW cm−2 at 650°C). The desired results underscore the feasibility of the Ir‐doping strategy as an optimized method for the exploitation of advancing cathode in SOFCs.

Prussian White/Reduced Graphene Oxide Composite as Cathode Material to Enhance the Electrochemical Performance of Sodium-Ion Battery

Prussian White/Reduced Graphene Oxide Composite as Cathode Material to Enhance the Electrochemical Performance of Sodium-Ion Battery

Optimizing high-energy lithium-ion batteries: a review of single crystalline and polycrystalline nickel-rich layered cathode materials: performance, synthesis and modification

Layered Ni-rich Li [NixCoyMnz]O2 (NMC) and Li [NixCoyAlz]O2 (NCA) cathode materials have been used in the realm of extended-range electric vehicles, primarily because of their superior energy density, cost-effectiveness, and commendable rate capability. However, they face challenges such as structural instability, cation mixing, and surface degradation, which limit their practical application. This review comprehensively discusses the synthesis, modification, and performance optimization of nickel-rich cathodes, with a focus on single-crystal (SC) NMC cathodes. The unique properties and challenges of single-crystal nickel-rich cathodes are explored in comparison to polycrystalline (PC) cathodes, with a focus on performance-enhancing strategies such as doping and surface modification.

Earth-abundant Li-ion cathode materials with nanoengineered microstructures

AbstractManganese-based materials have tremendous potential to become the next-generation lithium-ion cathode as they are Earth abundant, low cost and stable. Here we show how the mobility of manganese cations can be used to obtain a unique nanosized microstructure in large-particle-sized cathode materials with enhanced electrochemical properties. By combining atomic-resolution scanning transmission electron microscopy, four-dimensional scanning electron nanodiffraction and in situ X-ray diffraction, we show that when a partially delithiated, high-manganese-content, disordered rocksalt cathode is slightly heated, it forms a nanomosaic of partially ordered spinel domains of 3–7 nm in size, which impinge on each other at antiphase boundaries. The short coherence length of these domains removes the detrimental two-phase lithiation reaction present near 3 V in a regular spinel and turns it into a solid solution. This nanodomain structure enables good rate performance and delivers 200 mAh g−1 discharge capacity in a (partially) disordered material with an average primary particle size of ∼5 µm. The work not only expands the synthesis strategies available for developing high-performance Earth-abundant manganese-based cathodes but also offers structural insights into the ability to nanoengineer spinel-like phases.

Effect of electrolyte level on performance and mass transfer of non-aqueous lithium-oxygen battery

To accurately reveal the effect of electrolyte content on mass transfer within lithium-oxygen batteries and their discharge performance, this study utilizes computed tomography(CT) scanning technology and digital reconstruction methods to construct a geometric model of the lithium-oxygen battery cathode that is equivalent to the actual one. Based on the fundamental principles of mass transfer, fluid dynamics, and electrochemistry, a two-dimensional model for the discharge process of lithium-oxygen batteries is established. This model facilitates analysis of various parameters and their influencing factors, including the distribution of reaction products, pore structure, oxygen concentration distribution, battery performance, and overpotential, within the lithium-oxygen battery cathode. The research findings indicate that the deposition of reaction products alters the cathode structure and material transport; lower discharge current density and higher electrolyte levels are conducive to the dispersed deposition of reaction products, thereby reducing the deposition's resistance to internal mass transfer in the cathode.

Constructing three-dimensional GO/CNT@NMP aerogels towards primary lithium metal batteries

Abstract Graphene oxide (GO) can serve as cathode material for a viable primary lithium metal battery due to its richness in oxygen-containing functional groups. However, its application is hindered by non-conductivity of GO. Herein, a proposed electrode structure design strategy is carried to regulate the electron and ion conductivity of the graphene oxide aerogel (GO/CNT@NMP) electrode while retaining the original energy density. GO/CNT@NMP exhibits a discharge specific capacity of 703 mAh g−1 and an ultra-high energy density of 1655.76 Wh kg−1 at a low rate of 0.02 A g−1. Additionally, it achieves a maximum discharge rate of 1.4 A g−1, five times higher than the initial maximum discharge rate of GO. Characterization and electrochemical tests reveal that the excellent performance of GO/CNT@NMP can be attributed to its porous structure, high electrical conductivity, and large layer spacing. This study presents a potent strategy for the advancement of ultra-fast primary batteries, aiming to integrate ultra-high energy density and high-rate discharge capabilities.

Conducting LixPOy Interface Generated From Insulating Residual Lithium Compounds on LiNi0.8Mn0.1Co0.1O2 Surface Improves Cycle Life and Assists in Fast Cycling.

LiNi0.8Mn0.1Co0.1O2 (NMC811) is the most promising cathode material for future Li-ion batteries (LIBs). However, the bulk and surface structural instabilities retard its commercial success. Surface chemical instability toward exposure to moisture (H2O and CO2) leads to the formation of residual lithium compounds (RLCs: Li2CO3, LiOH) on the surface. The alkaline RLCs form a resistive layer on the surface of NMC811 by undergoing parasitic side reactions with electrolytes. Herein, an "Adverse-to-Beneficial" approach is proposed to eliminate RLCs by chemically transforming them into a LixPOy (Li3PO4 and LiPO3) interface. The interface protects the NMC811 surface from moisture attack and unwanted side reactions with electrolytes. It enhances the cycle life by retaining 70% of the initial capacity after 300 cycles at a 0.5C rate and 60% after 500 cycles, even at a 5C rate in a voltage window of 3.0-4.3V versus Li+/Li. The coexistence of two Li-conducting phases lowers the voltage polarization of the kinetically sluggish H1 → M phase transition to unlock fast cycling, reduces cationic disorder, improves coulombic efficiency, enhances ion diffusion kinetics, and minimizes particle crack formation after long-term cycling. Hence, the LixPOy interface yields multifaceted benefits in the storage, processing, and electrochemistry of NMC811.

Challenges and Prospects of Electrolyte Design for Lithium‐Sulfurized Polyacrylonitrile Batteries

Sulfurized polyacrylonitrile (SPAN) is regarded as a promising organic sulphur cathode material for lithium‐sulfur (Li‐S) batteries. It undergoes a solid‐solid conversion without forming polysulfide intermediate phases, overcoming the poor electrochemical performance caused by the shuttle effect of elemental S cathodes. However, the realization of this unique conversion mechanism requires to employ appropriate electrolytes. Furthermore, the direct application of metallic Li as the anode unavoidable introduces a series of issues triggered by Li dendrites in Li‐SPAN batteries, such as low lifespan, short circuits, fire, etc. In this review, we endeavor to encapsulate recent advancements in electrolyte research, with a particular focus on the intrinsic relationship between the solvation structure of the electrolyte and the interfacial chemistry of the Li anode and SPAN electrode, aim to provide insights into the electrolytes design for high performance Li‐SPAN full batteries.

Surface Reconstruction Enhanced Li-Rich Cathode Materials for Durable Lithium-Ion Batteries.

Regulating the distribution of surface elements in lithium-rich cathode materials can effectively change the electrochemical performance of cathode materials. Considering that the enrichment of Mn element on the surface is the main reason for the irreversible phase transition and dissolution of its surface structure, which in turn is the main reason for performance degradation. Based on the molten salt-assisted sintering method, a lithium rich cathode material with surface rich Ni and Co is designed and prepared. The surface enrichment of Ni and Co effectively reduces the dissolution of Mn, promotes the occurrence of irreversible collapse of surface structure from layered phase to rock salt phase on the material surface, improves the stability of surface crystal phase structure, and improves the cycling stability of positive electrode materials. Notably, after 500 cycles at 1 C current density, the discharge-specific capacity attained 189.8 mAh g -1, with a capacity retention rate of 88.9%, indicating a 42.1% improvement in capacity retention. Molten salt treatment is widely used in the modification of positive electrode materials. The research work will provide new ideas for improving the stability of lithium rich materials and promoting their commercial applications.

Cluster intercalation of aluminum tetrachloride in AlN cathode: Exploration and analysis of aluminum ion batteries.

When chloroaluminate (AlCl4-) serves as the electrolyte, aluminum nitride (AlN) has shown promise as a cathode material in aluminum ion batteries. However, there is currently a lack of research on the mechanisms of charge transfer and cluster intercalation between AlCl4 and AlN cathode materials. Herein, first-principles calculations are employed to investigate the intercalation mechanism of AlCl4 within the AlN cathode. By calculating the formation energies of stage-1-5 AlN-AlCl4 intercalation compounds with the insertion of individual AlCl4 cluster, we found that the structure of the stage-4 intercalation compounds exhibits the highest stability, suggesting that when the clusters begin to intercalate, it is important to start with the formation of the stage-4 intercalation compounds. In the subsequent phases of the charging process (stages 1 and 2), the stabilized structure with four inserted clusters demonstrates two characteristics: the coexistence of standing and lying clusters and the insertion of two standing clusters in an upside-down doubly stacked configuration, which further improve the spatial utilization while maintaining the structural stability. In addition, we infer that a phenomenon of coexisting intercalation compounds with mixed stages will occur in the course of the charging and discharging processes. More importantly, the diffusion barrier of AlCl4 in AlN-AlCl4 intercalation compounds decreases with the reduction of stage number, ensuring the rate performance of batteries. Therefore, we expect that our work will contribute to comprehend the intercalation mechanism of AlCl4 into the AlN cathode materials of aluminum ion batteries, providing guidance for related experimental work.

Iron Hexadecafluorophthalocyanine Nanoparticle/Porous Carbon Composites as Cathode Materials for Li–S Batteries

Iron Hexadecafluorophthalocyanine Nanoparticle/Porous Carbon Composites as Cathode Materials for Li–S Batteries

Optimized Tungsten Disulfide via Pyrolytic Deposition for Improved Zn‐ion Batteries

The selection and optimization of cathode materials are crucial for enhancing the performance of aqueous zinc‐ion batteries. In this work, different active materials were created by combining sulphur powder and polydopamine in four different mass ratios. The novel N‐doped carbon/WS2 is obtained. Thanks to the optimization of the dopamine‐carrying tungsten ion precursor and sulfur powder (1:2, 1:4, 1:6 and 1:8), the four samples exhibited diffenert morphology. The N‐C/WS2‐6‐based zinc ion batteries with the highest specific capacity, 120.0 mAh/g in the first discharge at 2.0 A/g, and 78.0 mAh/g after 2500 cycles, with a capacity retention of 65%, had a relatively good overall performance, according to the results. The reaction kinetics characteristics of the N‐C/WS2‐6 cathode reveal that enhanced pseudocapacitive behavior facilitates the diffusion of Zn2+

Synergistic interface engineering of ZnCo2O4/NiMnCo-layered double hydroxides for boosted reactivity in advanced supercapacitor electrodes

NiMn layered double hydroxide (LDH) exhibits high redox activity as a cathode material for hybrid supercapacitors, but it has the disadvantages of low conductivity and poor stability. In this work, the electrochemical properties of NiMnCo-LDH with different Co contents prepared by electrodeposition were tested. The results showed that the addition of an appropriate amount Co increased the adsorption of OH− on NiMn-LDH and improved the reactivity of the material. ZnCo-MOF grown on carbon cloth was transformed into flake ZnCo2O4 by calcination, and NiMnCo-LDH was electrodeposited on it to prepare ZnCo2O4/NiMnCo-LDH composite electrode. The core-shell structure increases the reaction area between the LDH material and the electrolyte. Physical characterization and density functional theory (DFT) calculations show that the structure and electronic distribution of ZnCo2O4/NiMnCo-LDH at the heterogeneous interface are reconstructed, which increases the valence state of Co and Mn elements, and finally exhibits enhanced electrochemical performance. Due to the existence of this synergistic effect, the specific capacity of the electrode is as high as 231.5 mAh g−1, with excellent stability demonstrated after 5000 cycles compared to the NiMnCo-LDH. The assembled hybrid supercapacitor exhibits a high energy density of 39.4 Wh kg−1, and has high cycle stability (90 % after 5000 cycles).

Heterostructure VO2@VS2 tailored by one-step hydrothermal synthesis for stable and highly efficient Zn-ion storage

Abstract The increasing demand for advanced energy storage solutions has driven extensive research into Zn-ion batteries due to their safety, cost-effectiveness, and environmental compatibility. This study presents a synthesis and evaluation of VO2@VS2 hollow nanospheres as a novel cathode material for Zn-ion batteries. The VO2@VS2 composite, synthesized via a one-step hydrothermal method, demonstrates a significant improvement in electrochemical performance. The material exhibits a reversible capacity of 468 mAh g−1 at 0.1 A g−1 and maintains a high capacity of 237 mAh g−1 at 1.0 A g−1 over 1000 cycles with a retention rate of 85%. Electrochemical analyses reveal enhanced charge transfer and Zn-ion storage, attributed to the synergistic effect and built-in electric field of the VO2 and VS2 heterostructure. Additionally, the composite shows superior electrochemical kinetics, facilitating rapid ion transport and charge transfer. In-situ Raman analysis confirms the reversible Zn-ion storage mechanism, further validating the composite’s structural stability during cycling. Density functional theory calculations further support these findings, indicating the composite’s potential for high-rate capability and long-term cycling stability. This research highlights the promise of VO2@VS2 hollow nanospheres in advancing the performance of aqueous Zn-ion batteries.

Highly efficient recovery of lithium from spent ternary NCM cathode materials via a selective chlorination method

The recovery of lithium from spent lithium-ion batteries (LIBs) is an important approach to solve the global shortage of lithium resource. Considering the difference in stability of various metal element chlorides in Ni-Co-Mn ternary (NCM) cathode materials, lithium element was selectively and high-efficiently extracted from spent ternary NCM cathode material by ammonium chloride roasting in oxygen atmosphere followed by water leaching. The effects of roasting temperature, roasting time, and NH4Cl dosage on lithium leaching efficiency and selectivity were systematically investigated. In addition, the conversion mechanism during chloride roasting was discussed in detail in conjunction with thermodynamic analysis as well as structural and compositional characterizations. After roasting with NH4Cl in oxygen atmosphere at 600°C, the spent NCM cathode material was thoroughly decomposed and converted into mixture of LiCl, NiO, and MnCo2O4. Due to the high aqueous solubility of LiCl, more than 95 % of the lithium in the mixture was leached in ∼30 minutes at room temperature, and Li2CO3 with a purity of 99.40 % can be obtained in the subsequent recovery process. This simple and efficient method can be generally useful for the recovery of a wide range of spent cathode materials and provide inspiration for the lithium recovery process of spent LIBs.

Sr0.7R0.3CoO3-δ (R = Gd, Eu, and Sm) Perovskites Infiltrated with Pd: Enhancing the Performance as Cathode Materials in Solid Oxide Fuel Cells

Sr_0.7R_0.3CoO_3-δ (R = Gd, Eu, and Sm) Perovskites Infiltrated with Pd: Enhancing the Performance as Cathode Materials in Solid Oxide Fuel Cells

Study of burst mode for enhancing the ps-laser cutting performance of lithium-ion battery electrodes

The demand for lithium-ion batteries (LIBs) has increased significantly, leading to an increased focus on high quality production methods. In response to this growing demand, laser technology has been increasingly used for electrode notching and cutting. In addition, the advent of high-power ultrashort lasers equipped with burst mode capabilities represents a promising option for electrode cutting of LIBs. On the other hand, these types of lasers for this purpose are relatively unexplored in the literature. This study investigates the effect of various parameters, including the number of pulses per burst (ranging from 1 to 8), the pulse repetition rate (200.0, 550.3, and 901.0 kHz), and the burst shape (equal pulse peak and increasing pulse peak), on the laser cutting process of aluminum foil, cathode, copper foil, and anode. The results indicate that increasing the number of pulses per burst and the pulse repetition rate improves productivity and quality for all materials, with a more significant effect observed for metal foil than for cathode and anode materials due to the different laser-material interactions for metal foil and active material. The burst shape with equal pulse peaks was found to be a more suitable temporal distribution for cutting all materials compared to an increasing pulse peak distribution. The ablation efficiency was evaluated as a function of the peak fluence of a single pulse within the burst. The results emphasize that higher productivity at higher average power can be achieved by increasing the pulse repetition rate toward the MHz range with moderate pulse energies.

Development of electrode and electrolyte materials for solid-state batteries based on Li1.3Al0.3Ti1.7(PO4)3

Abstract The dependence of the electrochemical characteristics of a layered cathode material containing LiNi0.5Mn0.3Co0.2O2 on the method for applying a protective layer of nanoparticles of the lithium-conducting material Li1.3Al0.3Ti1.7(PO4)3 with a NASICON structure to its surface has been studied. The surface modification has been found to improve the capacity retention in prolonged charge/discharge cycling (up to 15%) and to allow fast charge/discharge processes. The possibility of using a composite electrolyte consisting of a porous ceramic matrix of aluminum-substituted lithium titanium phosphate Li1.3Al0.3Ti1.7(PO4)3 with a transition layer of liquid electrolyte LP-71 has been shown. The use of a thick composite solid electrolyte results in a slight reduction (~5-7 mAh/g) in initial capacity compared to laboratory cells with the widely used Celgard 2400 separator impregnated with liquid electrolyte. Laboratory cells assembled with a composite electrolyte showed higher stability during charge/discharge cycling: after 80 deep charge/discharge cycles, the capacity reduction was ~12% for cells with a composite electrolyte, while for the reference cell it was ~23%.

Unraveling Energy Storage Performance and Mechanism of Metal-Organic Framework-Derived Copper Vanadium Oxides with Tunable Composition for Aqueous Zinc-Ion Batteries.

Achieving high-performance aqueous zinc (Zn)-ion batteries (AZIBs) requires stable and efficient cathode materials capable of reversible Zn-ion intercalation. Although layered vanadium oxides possess high Zn-ion storage capacity, their sluggish kinetics and poor conductivity present significant hurdles for further enhancing the performance of AZIBs. In response to this challenge, a dissolution-regrowth and conversion approach is formulated using metal-organic frameworks (MOFs) as a sacrificial template, which enables the in situ creation of copper vanadium oxides (CuVOx) with porous 1D channels and distinctive nanoarchitectures. Owing to their distinctive structure, the optimized CuVOx cathode experiences a reaction involving the synergistic insertion/extraction of Zn2+, resulting in rapid Zn2+ diffusion kinetics and enhanced electrochemical activity postactivation. Specifically, the activated electrode delivers a reversible capacity of 519mAhg-1 at 0.5Ag-1 for AZIBs. It is noteworthy that the electrode exhibits a remarkable reversible rate capacity of 220mAhg-1 at 5Ag-1 with excellent durable cycleability, retaining 88% of its capacity even after 3000 cycles. Various ex situ testing methods endorse the reversible insertion/extraction of Zn2+ in the CuVOx cathode. This study provides a novel insight into high-performance MOF-derived unique structure designs for AZIB electrodes.