Cathode Material Research Articles

Chitosan‐Decorated Alumina Hybrid Nanoparticles as Smart Scavengers of HF and Dissolved Transition Metals in Lithium‐Ion Batteries

AbstractLithium‐ion cells encompassing LiPF6 as the lithium salt and high‐voltage (LiNi0.5Mn1.5O4, LNMO) or high‐capacity (LiNi0.8Mn0.1Co0.1O2, NMC811) cathode materials are prone to transition metal (TM) dissolution caused by HF, whose formation is catalyzed by H2O traces. TM ions can shuttle to the anodic compartment, increasing the cell degradation rate. Accordingly, specific self‐healing strategies are helpful to develop scavengers able to eliminate HF and absorb TM ions so avoiding their shuttling. In this work, the fabrication and test of a bi‐functional, autonomous scavenging agent made of Al2O3 particles decorated is reported with chitosan. The nanometric Al2O3 core is a trap for HF by chemical bonding. The chitosan coating is acid‐sensitive, and the opening of such a capping layer is triggered in the presence of even small amounts of HF, leading to an efficient TM ion‐trapping. In addition, chitosan is biocompatible, biodegradable, and abundant, which is relevant for design‐for‐recycling scopes. With ≈200 ppm of water in the electrolyte, 12 wt% of scavenger causes, after 200 cycles at 1C, an increase of capacity retention from 73% to 88% for LNMO, and, impressively, from 46% to 84% for NMC811. This autonomous self‐healing mechanism is promising for application in next‐generation smart cells without requiring any external sensing.

Hydrothermal synthesis of αILiVOPO4 as a cathode material for Li-ion batteries

This paper presents the synthesis of a novel cathode material, αI-LiVOPO4, featuring a porous multilayered lamellar structure, achieved through the hydrothermal method. Initially, αI-LiVOPO4·2 H2O was synthesized by maintaining a reaction kettle at 160 °C for 40 h. Subsequently, the parent compound underwent dehydration at various temperatures for 2 h to yield αI-LiVOPO4. The dehydration process was investigated through thermogravimetric analysis. Analysis via powder X-ray diffraction confirmed the crystallization of the product into the αI-LiVOPO4 phase. TEM and EDS analyses revealed an irregular porous structure with uniform distribution of elements. The electrochemical performance of αI-LiVOPO4 was evaluated through constant current charge-discharge tests within a voltage range of 3–4.5 V. Results demonstrated an initial capacity of 106.9 mAh·g–1 at 0.05 C, with a capacity retention of 100.9 mAh·g–1 after the 50th cycle. Additionally, cyclic voltammetry indicated favorable cycling performance and minimal polarization at elevated voltages.

High cycling stability of MnO2 cathode for aqueous Mg-ion batteries enabled by Fe doping

MnO2 has been widely investigated as a promising cathode material for aqueous magnesium-ion batteries, which, however, suffers from the severe capacity fading during charge/discharge cycling. In present work, we report that the doping of Fe in α-MnO2 enlarges the lattice and alleviates the Jahn–Teller distortions and thus accelerates the Mg2+ diffusion and strengthens the structural stability. Consequently, the capacity retention remarkably increases from 44.3 % to 85.2 % after 1000 cycles by Fe doping. Furthermore, it is found for the first time that Fe doping enables the co-insertion of H+ and Mg2+ in the tunnels of α-MnO2, which improves remarkably the specific capacity from 131.9 to 205.9 mA h g−1 at 0.1 A g−1.

Innovations and strategies for optimizing lithium-ion battery performance: From material advancements to system management

This paper explores the multifaceted advancements in lithium-ion battery (LIB) technology, focusing on material innovations and engineering strategies aimed at optimizing performance, safety, and efficiency. We delve into the development of advanced cathode materials like lithium nickel manganese cobalt oxide (NMC) and lithium iron phosphate (LFP), highlighting their contributions to enhancing energy density and safety. The investigation extends to silicon-based anode materials, underscoring their potential to significantly increase energy storage capacity despite challenges related to volume expansion. Furthermore, we discuss electrolyte optimization techniques that promise to improve battery safety through the use of non-flammable ionic liquids and solid-state electrolytes. Engineering strategies, including microstructure design of electrodes and thermal management systems, are analyzed for their role in improving electrochemical performance and extending battery lifespan. Smart battery management systems (BMS) are also examined for their ability to optimize battery usage through real-time monitoring and predictive analytics. Through a comprehensive review and quantitative analysis, this study presents a cohesive overview of current trends and future directions in LIB technology.

Comparative Analysis of Lithium-Ion Batteries for Urban Electric/Hybrid Electric Vehicles

This paper presents an experimental comparison of two types of Li-ion battery stacks for low-voltage energy storage in small urban Electric or Hybrid Electric Vehicles (EVs/HEVs). These systems are a combination of lithium battery cells, a battery management system (BMS), and a central control circuit—a lithium energy storage and management system (LESMS). Li-Ion cells are assembled with two different active cathode materials, nickel–cobalt–aluminum (NCA) and lithium iron phosphate (LFP), both with an integrated decentralized BMS. Based on experiments conducted on the two assembled LESMSs, this paper suggests that although LFP batteries have inferior characteristics in terms of energy and power density, they have great capacity for improvement.

Can Aluminum Impurity from Current Collectors Upgrade Spent Li1‐xCoO2 into a High‐Performing Cathode for Lithium‐Ion Batteries?

AbstractThe recycling of spent lithium‐ion batteries (LIBs) is gaining considerable attention for its potential to address resource scarcity and mitigating environmental pollution. Therefore, the recycling process of spent LIBs should be simple and efficient and minimize the input of raw materials. This work uses residual Al impurities from current collectors combined with high‐temperature Li supplementation to directly repair spent Li1‐xCoO2 cathode into regenerated materials enhanced with Al doping and LiF coating without additional synthesis steps or cost. The regenerated materials demonstrate an enhanced electrochemical performance compared to commercial cathode material. The modified materials exhibit a notable initial discharge capacity of 181 mA h g−1, with a commendable capacity retention of 80.4% after 400 cycles at a 4.5 V cut‐off voltage. The improved electrochemical performance is attributed to the enhanced crystalline and structural stability of the regenerated materials. Furthermore, the superiority of spent materials over commercial materials modification is clarified for the first time through characterizations and theoretical calculations due to their degraded crystalline structure and abundant Li vacancies. This up‐cycling strategy not only contributes to sustainable waste management of spent LIBs but also provides a potential “shortcut” for advancing next‐generation high‐performance batteries.

Enhancement of the electrochemical properties of the nickel-rich cathode material LiNi0.815Co0.15Al0.035O2 by WO3 coating

Enhancement of the electrochemical properties of the nickel-rich cathode material LiNi0.815Co0.15Al0.035O2 by WO3 coating

Improved ACOM pattern matching in 4D-STEM through adaptive sub-pixel peak detection and image reconstruction

The technique known as 4D-STEM has recently emerged as a powerful tool for the local characterization of crystalline structures in materials, such as cathode materials for Li-ion batteries or perovskite materials for photovoltaics. However, the use of new detectors optimized for electron diffraction patterns and other advanced techniques requires constant adaptation of methodologies to address the challenges associated with crystalline materials. In this study, we present a novel image-processing method to improve pattern matching in the determination of crystalline orientations and phases. Our approach uses sub-pixel adaptive image processing to register and reconstruct electron diffraction signals in large 4D-STEM datasets. By using adaptive prominence and linear filters, we can improve the quality of the diffraction pattern registration. The resulting data compression rate of 103 is well-suited for the era of big data and provides a significant enhancement in the performance of the entire ACOM data processing method. Our approach is evaluated using dedicated metrics, which demonstrate a high improvement in phase recognition. Several features are extracted from the registered data to map properties such as the spot count, and various virtual dark fields, which are used to enhance the handling of the results maps. Our results demonstrate that this data preparation method not only enhances the quality of the resulting image but also boosts the confidence level in the analysis of the outcomes related to determining crystal orientation and phase. Additionally, it mitigates the impact of user bias that may occur during the application of the method through the manipulation of parameters.

Laser-Scribed Battery Electrodes for Ultrafast Zinc-Ion Energy Storage.

Aqueous Zn batteries are promising for large-scale energy storage applications but are plagued by the lack of high-performance cathode materials that enable high specific capacity, ultrafast charging, and outstanding cycling stability. In this work, we design a laser-scribed nano-vanadium oxide (LNVO) cathode that can simultaneously achieve these properties. Our material stores charge through Faradaic redox reactions on/near the surface at fast rates owing to the small grain size (2-6nm) of vanadium oxide and interpenetrating three-dimensional (3D) graphene network, displaying a surface-controlled capacity contribution (90%-98%). Multiple characterization techniques unambiguously reveal that zinc and hydronium ions co-insert with minimal LNVO lattice change upon cycling. As a result, we demonstrate that a high specific capacity of 553 mAh g-1 can be achieved by the LNVO/Zn system at 0.1 A g-1 , and an impressive 264 mAh g-1 capacity can be retained at 100 A g-1 with a 10 s charge/discharge cycle, showing excellent rate capability. The LNVO/Zn is also capable of reaching >90% capacity retention after 3,000 cycles at a high rate of 30 A g-1, as well as achieving both high energy (369Wh kg-1) and power densities (56,306W kg-1). Moreover, the LNVO cathode retains its excellent cycling performance when integrated into quasi-solid-state pouch cells, further demonstrating mechanical stability and its potential for practical application in wearable and grid-scale applications. This article is protected by copyright. All rights reserved.

Tailoring of High-Valent Sn-Doped Porous Na3V2(PO4)3/C Nanoarchitechtonics: An Ultra High-Rate Cathode for Sodium-Ion Batteries.

NASICON structured Na3V2(PO4)3 (NVP) has captured enormous attention as a potential cathode for next-generation sodium-ion batteries (SIBs), owing to its sturdy crystal structure and high theoretical capacity. Nonetheless, its poor intrinsic electronic conductivity has led to inferior electrochemical performance in terms of rate capability and long cycling performance. To address this problem, a combined strategy is adopted, such as (1) carbon coating and (2) high valent Sn4+ ion doping in the lattice site of vanadium in the NVP cathode. Carbon coating can effectively enhance the surface electronic conductivity, wherein high-valent Sn4+ improves the bulk intrinsic electronic conductivity of the materials. Moreover, Sn is a well-known alloying/dealloying type anode for SIBs; thus, doping of such metal in cathode materials will assume the role of structure stabilizing pillars and establishing high-performing cathode materials. Herein, Na3V2-xSnx(PO4)3/C (denoted as Sn(x)-NVP/C, where x = 0.00, 0.03, 0.05, 0.07, 0.1) were synthesized via sol-gel route, followed by calcination at 800 °C. XRD, Raman, XPS, and electron microscopy data confirmed the high purity of the synthesized cathode. The optimized Sn(0.07)-NVP/C exhibited excellent electrochemical performance in terms of high rate capability and long cycling performance, a high appreciable capacity of 98 mAh g-1 with capacity retention of 85% after 500 cycles. Similarly, at a high current of 20C, it is still able to deliver a stable capacity of 76 mAh g-1 with 85% capacity retention after 3000 cycles. The rate capability study indicates the high current tolerance of Sn(0.07)-NVP/C up to 70 C with a capacity delivery of 55 mAh g-1. It is worth mentioning that CV and EIS analysis for Sn(0.07)-NVP/C cathode displayed minimum voltage polarization and enhanced diffusion coefficient. Moreover, DFT calculation also proved that the electronic and ionic conductivity of NVP is promoted by Sn doping. Hence, the present results demonstrated that Sn(0.07)-NVP/C is considered a promising cathode for sodium-ion battery application.

Mitigating voltage decay of O3‐NaNi1/3Fe1/3Mn1/3O2 layered oxide cathode for sodium‐ion batteries by incorporation of 5d metal tantalum

AbstractThe cycling stability of O3‐type NaNi1/3Fe1/3Mn1/3O2 (NFM) as a commercial cathode material for sodium ion batteries (SIBs) is still a challenge. In this study, the Ni/Fe/Mn elements are replaced successfully with tantalum (Ta) in the NFM lattice, which generated additional delocalized electrons and enhanced the binding ability between the transition metal and oxygen, resulting in suppressed lattice distortion during charging and discharging. This caused significant mitigation of voltage decay and improved cycle stability within the potential range of 2.0–4.2 V. The optimized Na(Ni1/3Fe1/3Mn1/3)0.97Ta0.03O2 sample achieved a reversible capacity of 162.6 mAh g−1 at a current rate of 0.1 C and 73.2 mAh g−1 at a high rate of 10 C. Additionally, the average charge/discharge potential retention reached 98% after 100 cycles, significantly mitigating the voltage decay. This work demonstrates a significant contribution towards the practical utilization of NFM cathodes in the SIBs energy storage field.

Constructing partially spinel phase in Mn-rich cathode material

As a cathode with earth-abundant element, Mn-rich oxide has been explored to enable the scaling of the Li-ion battery. However, the irreversible transition metals migration and phase transformations in Mn-rich materials have been proven to be detrimental, which trigger capacity degradation, voltage decay, and poor kinetics. In this work, using Li2MnO3 as model, spinel-layered biphase was constructed via Ti doping and de-lithiation modification, which exhibits higher available capacity of 236.9 mAh/g (55.6 mAh/g for pristine material) and improved rate performance. Compared with pristine Mn-based cathodes, the new phase delivers neglectable voltage degradation during electrochemical cycling. Based on systematic characterization, the new phase exhibits higher oxygen redox reversibility and accelerated kinetics of lithium ions transformation. This work provides a new strategy for designing high-energy density Mn-rich cathodes.

Cycling performance of layered oxide cathode materials for sodium-ion batteries

Cycling performance of layered oxide cathode materials for sodium-ion batteries

Synthesis of binder-free hydrated vanadium oxide-polyaniline electrodes via in situ polymerization for high-performance aqueous zinc-ion batteries

Hydrated vanadium oxide, a kind of layered electrode material with high theoretical specific capacity, has great potential for developing high-performance, low-cost, and eco-friendly aqueous zinc-ion batteries. However, its characteristics of poor electronic conductivity, vanadium dissolution, and unstable structure lead to poor electrochemical performance, such as low specific capacity, poor rate performance and short cycle life. Combining PANI with layered hydrated vanadium oxide is expected to overcome the shortcomings and achieve high zinc storage performance. In this work, binder-free hydrated vanadium oxide-polyaniline inorganic–organic hybrid compounds deposited on carbon cloth (VOH-PANI/CC) are developed by combination of layer-by-layer and in-situ polymerization process. Benefiting from synergistic effect between polyaniline and hydrated vanadium pentoxide, the hybrid electrode (VOH-PANI/CC) delivers high capacities of 290 mA h/g at 0.5 A/g and 165 mA h/g at 4 A/g. In contrast, the specific capacities of VOH/CC are only 185 and 70 mA h/g at 0.5 and 4 A/g, respectively. This in-situ polymerization of aniline via layer-by-layer strategy on hydrated vanadium oxide provides a novel synthesis scheme for the use of vanadium oxide as cathode material for aqueous zinc-ion batteries.

Surface Encapsulation of Layered Oxide Cathode Material with NiTiO3 for Enhanced Cycling Stability of Na-Ion Batteries

Abstract In Na-ion batteries, O3-type layered oxide cathode materials encounter challenges such as particle cracking, oxygen loss, electrolyte side reactions, and multi-phase transitions during the charge/discharge process. This study focuses on surface coating with NiTiO3 achieved via secondary heat treatment using a coating precursor and the surface material. Through in-situ X-ray diffraction (XRD) and differential electrochemical mass spectrometry (DEMS), along with crystal structure characterizations of post-cycling materials, it was determined that the NiTiO3 coating layer facilitates the formation of a stable lattice structure, effectively inhibiting lattice oxygen loss and reducing side reaction with the electrolyte. This enhancement in cycling stability is evidenced by a capacity retention of approximately 74% over 300 cycles at 1C, marking a significant 30% improvement over the initial sample. Furthermore, notable advancements in rate performance were observed. Experimental results indicate that a stable and robust surface structure substantially enhances the overall stability of the bulk phase, presenting a novel approach for designing layered oxide cathodes with higher energy density.

First‐principles calculations on LaX3 (X: Sb, Sn) as electrode material for lithium‐ion batteries

AbstractUsing first‐principle calculations, we investigate the rare‐earth intermetallic compound LaX3 (X = Sb and Sn) as a cathode material for rechargeable lithium‐ion batteries (LIBs). The calculations have been performed to look into the stability of the structure and the electronic properties of host LaX3 as well as its lithiated phases, LixLa1−xX3 (0 < x ≤ 1). In this study, we have observed a structural phase transformation of these intermetallic compounds from a cubic to a tetragonal structure upon lithiation to host structure. The ground state energy is calculated using the WIEN2k package to determine the structure stability and volume change due to lithium addition, which is further used to calculate the formation energy, open circuit voltage (OCV), and lithium‐ion storage capacity. The equilibrium structural parameters for all the phases are determined by achieving a total energy convergence of 10−4 Ry. The estimated band structure along high‐symmetry lines in the first Brillouin zone and the total as well as partial density of states demonstrate unequivocally that the addition of lithium does not change the metallic nature of these electrode materials. We have also calculated the theoretical lithium‐ion storage capacity and OCV for all the compounds. Despite a higher value for OCV larger than 5 V, many of the investigated materials could not be found suitable from a synthesis point of view due to positive formation energies. The formation energy calculation shows that LaSb3, with a 50% concentration of Li, is the most stable compound out of those investigated here. The calculated OCV for Li0.5La0.5Sb3 is 4.27 V. This is substantially higher than the value obtained up to this point for LIBs, which ranges from 3.20 to 3.65 V/cell. These improved results related to the most stable alloy (Li0.5La0.5Sb3) investigated in this work indicate that it is necessary to check the experimental feasibility of its synthesis and actual device performance.

Metal-organic framework assisted design of ZnVOx cathode for aqueous zinc batteries at extreme work condition

Vanadium oxides with high Zn2+ storage capacity are desirable cathode materials for aqueous zinc-based batteries. However, their further application is hindered due to the slow electrochemical kinetics and low electronic conductivity. Herein, we design ZnVOx electrode materials with porous one-dimensional channels using ZIF-8 template as precursor. The unique structures provide sufficient reactive sites and spacious ion diffusion channels. The assembled Zn//2Zn-V2O5 batteries deliver a specific capacity of 526.6 mAh g-1 at 0.2 A g-1. They can charge/discharge stably for 7000 times and maintain a retention rate of 84 % at 10 A g-1. Moreover, they still work well within a wide temperature range from 30 to -40 oC. The flexible batteries also show excellent mechanical stability and durability.

Dual-Site Doping in Transition Metal Oxide Cathode Enables High-Voltage Stability of Na-Ion Batteries.

Designing cathode materials that effectively enhancing structural stability under high voltage is paramount for rationally enhancing energy density and safety of Na-ion batteries. This study introduces a novel P2-Na0.73K0.03Ni0.23Li0.1Mn0.67O2 (KLi-NaNMO) cathode through dual-site synergistic doping of K and Li in Na and transition metal (TM) layers. Combining theoretical and experimental studies, this study discovers that Li doping significantly strengthens the orbital overlap of Ni (3d) and O (2p) near the Fermi level, thereby regulates the phase transition and charge compensation processes with synchronized Ni and O redox. The introduction of K further adjusts the ratio of Nae and Naf sites at Na layer with enhanced structural stability and extended lattice space distance, enabling the suppression of TM dissolution, achieving a single-phase transition reaction even at a high voltage of 4.4V, and improving reaction kinetics. Consequently, KLi-NaNMO exhibits a high capacity (105 and 120 mAh g-1 in the voltage of 2-4.2V and 2-4.4V at 0.1 C, respectively) and outstanding cycling performance over 300 cycles under 4.2 and 4.4V. This work provides a dual-site doping strategy to employ synchronized TM and O redox with improved capacity and high structural stability via electronic and crystal structure modulation.

Enhancing Orbital Interaction in Spinel LiNi0.5Mn1.5O4 Cathode for High-Voltage and High-Rate Li-Ion Batteries.

High voltage cobalt-free spinel LiNi0.5Mn1.5O4 (LNMO) is well organized as a high-power cathode material for lithium (Li)-ion batteries, however, the weak interaction between the 3d orbital of the transition metal (TM) ions and the 2p orbital of oxygen (O) leads to the instability of crystal structural, hindering the long-term stable cycling of LNMO cathode especially at high temperatures. Here, a design strategy of orbital interaction is initiated to strengthen TM 3d-O 2p framework in P-doped LNMO (P-LNMO) by choosing phytic acid as P dopant, which can realize more uniform doping compared to regular phosphate. The results show that the enhancement of TM 3d-O 2p orbital interaction in P-LNMO can suppress the Jahn-Teller effect and subsequent dissolution of Mn, as well as lowers the energy barrier for Li ion insertion/extraction kinetics. As a result, superior electrochemical performances including high discharge capacity, stable cycling behavior and enhanced rate capability of P-LNMO are obtained. Significantly, the P-LNMO pouch cell shows great cycling stability with 97.4% capacity retention after 100 cycles.

Engineering Reversible Lattice Structure for High-Capacity Co-Free Li-Rich Cathodes with Negligible Capacity Degradation.

Co-free Li-rich Mn-based cathode materials are garnering great interest because of high capacity and low cost. However, their practical application is seriously hampered by the irreversible oxygen escape and the poor cycling stability. Herein, a reversible lattice adjustment strategy is proposed by integrating O vacancies and B doping. B incorporation increases TM─O (TM: transition metal) bonding orbitals whereas decreases the antibonding orbitals. Moreover, B doping and O vacancies synergistically increase the crystal orbital bond index values enhancing the overall covalent bonding strength, which makes TM─O octahedron more resistant to damage and enables the lattice to better accommodate the deformation and reaction without irreversible fracture. Furthermore, Mott-Hubbard splitting energy is decreased due to O vacancies, facilitating electron leaps, and enhancing the lattice reactivity and capacity. Such a reversible lattice, more amenable to deformation and forestalling fracturing, markedly improves the reversibility of lattice reactions and mitigates TM migration and the irreversible oxygen redox which enables the high cycling stability and high rate capability. The modified cathode demonstrates a specific capacity of 200 mAh g-1 at 1C, amazingly sustaining the capacity for 200 cycles without capacity degradation. This finding presents a promising avenue for solving the long-term cycling issue of Li-rich cathode.