Anode Material Research Articles

Lithium insertion/extraction mechanism in Mg2Sn anode for lithium-ion batteries

Due to its high capacity and excellent voltage properties, the Mg2Sn intermetallic phase is considered a promising anode material for next-generation lithium-ion batteries. However, the rapid capacity loss with cycling presently limits the application of Mg2Sn-based anodes. In this work, the Mg2Sn intermetallic phase was synthesized via a conventional casting method, and mechanisms of lithium ions intercalation into Mg2Sn alloy anodes were systematically studied. Density functional theory (DFT) calculations and electrochemical analyses identified two pathways involving four electrochemical reactions for Li+ intercalation/extraction in the Mg2Sn phase. The first pathway involves the insertion reaction of lithium ions into the octahedral sites of the Mg2Sn face center cubic (FCC) matrix, whilst the second involves the substitution of Mg by Li ions (releasing Mg metal). Furthermore, ex-situ EIS analysis and DFT calculations verified that adjusting the cut-off voltage range could control the reaction pathways. Excessively high or low cut-off voltages adversely impact the stability of the Mg2Sn anode. At cut-off voltages between 0.1 and 1 V, Mg2Sn anodes show very good capacity retention (78 % after 50 cycles), benefiting from the minimized formation of metallic Mg and Sn phases.

Electrokinetics in a Stone Column Encased by a Conductive Jute Geotextile: The Role of Anode Materials

Electrokinetics in a Stone Column Encased by a Conductive Jute Geotextile: The Role of Anode Materials

Ga-polymer dual interfacial layer modified Li metal for high-energy Li metal batteries

Lithium metal is regarded as the ultimate anode material for its extremely exceptional theoretical capacity and low reduction potential. Unfortunately, its practical utility has been constrained by changings such as the formation of lithium dendrites, volume expansion resulting from host-free structure, and uncontrollable side reactions with electrolyte. To achieve long cycle life, conventional single artificial layer strategy fails to solve due to ununiform lithium deposition problem. Consequently, the adoption of dual interfacial layer on lithium metal has emerged as prevailing strategy. In this study, we present a design of dual interface protective layer that combines a Ga-based liquid metal with the organic polymer Poly (ethylene glycol) diacrylate (PEGDA). This innovative combination offers synergistic benefits, including alleviate the volume effect and suppressing undesired interface side reactions. In practical test, the Li || Li symmetrical cell assembled from PEGDA LiGa dual interfacial layer maintains a low overpotential of 36.8 mV after 1400 h (2 mA cm−2, 2mAh cm−2). Moreover, even at a high rate of 5C, Li || LiNi0.8Co0.1Mn0.1O2 (NCM811, 1.0 mAh cm−2) cell still delivers a discharge capacity of 120 mAh g−1, 1.4 times higher than bare Li. Notably, when integrated into a pouch cell with a LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode (1.52 mAh cm−2), this dual interface layers ensures stable performance over 60 cycles, with a capacity retention of 82 %. In summary, this innovative dual interface layer design offers a promising approach to address the intricate challenges associated with lithium metal protection and interface modification.

Layer effects on MXenes electrode and it applied to silicon composite structures

Despite the very high capacity of Si (4200mAh g−1), the widespread application of Si anodes has been hampered by drastic volume changes (up to 300 %) during cycling, leading to electrical contact losses and thus a sharp drop in capacity as the cycle life is shortened. Here we present a class of layered MXene/Si electrodes, which consist of nano-Si embedded in the interlayers of MXene to form a coupling effect, which can inhibit the huge volume change of Si during cycling. Therefore, layered MXene/Si has a highly reversible capacity, much improved cycling performance and excellent mechanical properties. First-principles calculations reveal the excellent electronic conductivity and good diffusion ability of layered MXene/Si, confirming the rapid storage of Li ions. This study provides useful information for the development and production of anode materials with high energy density and good mechanical properties.

Fabrication of a Molybdenum Dioxide/Multi-Walled Carbon Nanotubes Nanocomposite as an Anodic Modification Material for High-Performance Microbial Fuel Cells

A nanocomposite of multi-walled carbon nanotubes (MWCNTs) decorated with molybdenum dioxide (MoO2) nanoparticles is fabricated through the reduction of phosphomolybdic acid hydrate on functionalized MWCNTs in a hydrogen–argon (10%) atmosphere in a tube furnace. The MoO2/MWCNTs composite is proposed as an anodic modification material for microbial fuel cells (MFCs). MWCNTs have outstanding physical and chemical peculiarities, with functionalized MWCNTs having substantially large electroactive areas. In addition, combined with the exceptional properties of MoO2 nanoparticles, the synergistic advantages of functionalized MWCNTs and MoO2 nanoparticles give a MoO2/MWCNTs anode a large electroactive area, excellent electronic conductivity, enhanced extracellular electron transfer capacity, and improved nutrient transfer capability. Finally, the power harvesting of an MFC with the MoO2/MWCNTs anode is improved, with the MFC showing long-term repeatability of voltage and current density outputs. This exploratory research advances the fundamental application of anodic modification to MFCs, simultaneously providing valuable guidance for the use of carbon-based transition metal oxide nanomaterials in high-performance MFCs.

Inhibition of Phase Transition in Amorphous Niobium Oxide by Covalent Carbon Reinforcement Enables Fast‐Charge and Long‐Duration Lithium Storage

AbstractNiobium oxides are potential anode materials for ultrafast and safe lithium‐ion batteries due to their high ionic conductivity and relatively high operation voltage. However, the electrochemically induced phase transformations that involve multi‐electron redox reactions in a wide voltage window cause rapid capacity degradation and poor rate capability. Here, a novel carbon‐covalent amorphous niobium oxide anode is reported to greatly suppress the phase transition during cycling via formation of strong Nb─O─C bonds, achieving high‐capacity, fast‐charge and long‐duration lithium storage. This amorphous structure and forming covalent carbon contribute to good volume accommodation and high electron conductivity. The carbon‐covalent amorphous Nb2O5 displays a high reversible capacity of 361.5 mAh g−1 at 0.1 A g−1 and excellent cycling stability with a capacity of 189.8 mAh g−1 at a high rate of 10 A g−1 after 9000 cycles. Structure characterizations reveal that the well‐preserved amorphous structure without phase transition during repeated Li+ insertion/desertion is responsible for the superior performance. This work opens a new avenue on rational design of high‐performance amorphous electrode materials for next‐generation batteries.

Facile Fabrication of Large-Area CuO Flakes for Sodium-Ion Energy Storage Applications

CuO is recognized as a promising anode material for sodium-ion batteries because of its impressive theoretical capacity of 674 mAh g−1, derived from its multiple electron transfer capabilities. However, its practical application is hindered by slow reaction kinetics and rapid capacity loss caused by side reactions during discharge/charge cycles. In this work, we introduce an innovative approach to fabricating large-area CuO and CuO@Al2O3 flakes through a combination of magnetron sputtering, thermal oxidation, and atomic layer deposition techniques. The resultant 2D CuO flakes demonstrate excellent electrochemical properties with a high initial reversible specific capacity of 487 mAh g−1 and good cycling stability, which are attributable to their unique architectures and superior structural durability. Furthermore, when these CuO flakes are coated with an ultrathin Al2O3 layer, the integration of the 2D structures with outer nanocoating leads to significantly enhanced electrochemical properties. Notably, even after 70 rate testing cycles, the CuO@Al2O3 materials maintain a high capacity of 525 mAh g−1 at a current density of 50 mA g−1. Remarkably, at a higher current density of 2000 mA g−1, these materials still achieve a capacity of 220 mAh g−1. Moreover, after 200 cycles at a current density of 200 mA g−1, a high charge capacity of 319 mAh g−1 is sustained. In addition, a full cell consisting of a CuO@Al2O3 anode and a NaNi1/3Fe1/3Mn1/3O2 cathode is investigated, showcasing remarkable cycling performance. Our findings underscore the potential of these innovative flake-like architectures as electrode materials in high-performance sodium-ion batteries, paving the way for advancements in energy storage technologies.

Unravelling Ultra‐Stable Conversion‐Type Zinc‐Ion Storage in Copper Selenides for Flexible Aqueous Batteries

AbstractRocking‐chair configurations based on advanced anodes with reliable zinc‐ion storage can intrinsically avoid the deterioration of flexible zinc‐ion energy devices by corrosion, dendrites, and inadequate mechanical stability of zinc metal, yet the identification of durable anode materials is still challenging. Herein, the first reported conversion‐type Cu2‐xSe is proposed as an ultra‐stable anode for flexible rocking‐chair aqueous zinc‐ion batteries. Differing from these well‐recognized intercalation‐type copper selenide anodes, the unique Cu2‐xSe structure features a preferred thermodynamic deep transformation path, and the high‐reversible conversion reaction is fully illuminated by in situ synchrotron X‐ray diffraction and substantial ex situ characterization, demonstrating an outstanding performance combination of high capacity (150 mAh g−1 at 0.5 A g−1) and record‐high stability (91% capacity retention after 20 000 cycles at 5 A g−1 in Cu2‐xSe||ZnxMnO2 full cells). Consequently, fiber‐shaped batteries using Cu2‐xSe as the anode are successfully assembled and exhibited an ultra‐long life (89.8% capacity retention after 900 cycles) and extraordinary flexibility (98% capacity retention after 4500 cycles of bending), far exceeding those of representative flexible batteries previously reported. The findings provide novel insights into the energy storage mechanism of copper selenides and, as an elegant forerunner, offer a plausible path for the development of rocking‐chair flexible aqueous zinc‐ion batteries.

Novel design of Sn4P3@NxC electrodes and their electrochemical properties

Tin phosphide (SnxPy) is recognized as one of the most promising anode materials for lithium-ion batteries due to its exceptionally high theoretical capacity. However, its application is hampered by significant volume expansion during charge-discharge cycles and inferior electrical conductivity. Proper structural design placs a pivotal role in addressing these challenges, paving the way for high-performance anode materials. This study introduces a nitrogen-doped carbon-coated Sn4P3 nanosphere with a core-shell structure, employing dopamine as the nitrogen source. This innovative approach, utilizing template removal and solid-phase phosphorization, results in both the core and shell acting as active materials, thereby enhancing the volumetric energy density of the electrode. The internal voids within the shell layer mitigate volume expansion during charge-discharge cycles, while the presence of the nitrogen-doped carbon layer maintains the material's stability throughout cycling and improves its electrical conductivity. Electrochemical performance tests confirm the outstanding energy storage capability of this material, with an initial Coulombic efficiency reaching up to 73.6 %. Furthermore, it maintains a stable capacity of 585 mAh g^-1 after 1200 cycles at a current density of 2 A g^-1. This research offers a design paradigm for the development of novel energy storage materials.

Core–Double-Shell TiO2@Fe3O4@C Microspheres with Enhanced Cycling Performance as Anode Materials for Lithium-Ion Batteries

Due to the volume expansion effect during charge and discharge processes, the application of transition metal oxide anode materials in lithium-ion batteries is limited. Composite materials and carbon coating are often considered feasible improvement methods. In this study, three types of TiO2@Fe3O4@C microspheres with a core–double-shell structure, namely TFCS (TiO2@Fe3O4@C with 0.0119 g PVP), TFCM (TiO2@Fe3O4@C with 0.0238 g PVP), and TFCL (TiO2@Fe3O4@C with 0.0476 g PVP), were prepared using PVP (polyvinylpyrrolidone) as the carbon source through homogeneous precipitation and high-temperature carbonization methods. After 500 cycles at a current density of 2 C, the specific capacities of these three microspheres are all higher than that of TiO2@Fe2O3 with significantly improved cycling stability. Among them, TFCM exhibits the highest specific capacity of 328.3 mAh·g−1, which was attributed to the amorphous carbon layer effectively mitigating the capacity decay caused by the volume expansion of iron oxide during charge and discharge processes. Additionally, the carbon coating layer enhances the electrical conductivity of the TiO2@Fe3O4@C materials, thereby improving their rate performance. Within the range of 100 to 1600 mA·g−1, the capacity retention rates for TiO2@Fe2O3, TFCS, TFCM, and TFCL are 27.2%, 35.2%, 35.9%, and 36.9%, respectively. This study provides insights into the development of new lithium-ion battery anode materials based on Ti and Fe oxides with the abundance and environmental friendliness of iron, titanium, and carbon resources in TiO2@Fe3O4@C microsphere anode materials, making this strategy potentially applicable.

Investigation of cathode properties of two-dimensional NbS2Cl2 for Li and Na-ion batteries using density functional theory

Exploring novel two-dimensional materials (2D) for electrode and electrochemical storage applications stands as a pivotal pursuit in advancing renewable energy technologies. While recent research has predominantly focused on anode materials, cathode materials have received comparatively lesser attention. This study delves into the potential cathode applications of the novel two-dimensional material NbS2Cl2 using density functional theory. Fundamental properties, encompassing electronic and thermodynamic attributes, were scrutinized to comprehend the material’s characteristics. Our investigation extended to examining the adsorption and diffusion properties of these electrode materials. Comprehensive calculations of mechanical and thermodynamic properties reaffirmed the stability of this system. Upon adsorption of Li/Na atoms, the conducting nature emerged, evident through charge density difference and projected density of states. Our findings notably reveal minimal diffusion barriers of 1.5 eV and 0.35 eV for Li and Na atoms. Moreover, the observed open circuit voltages for adsorbed Li and Na ions were 4.69 V and 2.62 V, respectively. The calculated theoretical capacity for adsorbed Li-ion on 2D-NbS2Cl2 is 400 mAh g−1, while for Na-ion adsorption, it is 353 mAh g−1, awaiting validation through future experimental verifications.

Lithium-Ion Dynamic and Storage of Atomically Precise Halogenated Nanographene Assemblies via Bottom-Up Chemical Synthesis.

Graphene has received much scientific attention as an electrode material for lithium-ion batteries because of its extraordinary physical and electrical properties. However, the lack of structural control and restacking issues have hindered its application as carbon-based anode materials for next generation lithium-ion batteries. To improve its performance, several modification approaches such as edge-functionalization and electron-donating/withdrawing substitution have been considered as promising strategies. In addition, group 7A elements have been recognized as critical elements due to their electronegativity and electron-withdrawing character, which are able to further improve the electronic and structural properties of materials. Herein, we elucidated the chemistry of nanographenes with edge-substituted group 7A elements as lithium-ion battery anodes. The halogenated nanographenes were synthesized via bottom-up organic synthesis to ensure the structural control. Our study reveals that the presence of halogens on the edge of nanographenes not only tunes the structural and electronic properties but also impacts the material stability, reactivity, and Li+ storage capability. Further systematic spectroscopic studies indicate that the charge polarization caused by halogen atoms could regulate the Li+ transport, charge transfer energy, and charge storage behavior in nanographenes. Overall, this study provides a new molecular design for nanographene anodes aiming for next-generation lithium-ion batteries.

Origin of the Activity of Electrochemical Ozone Production over Rutile PbO2 Surfaces.

Ozonation water treatment technology has attracted increasing attention due to its environmental benign and high efficiency. Rutile PbO2 is a promising anode material for electrochemical ozone production (EOP). However, the reaction mechanism underlying ozone production catalyzed by PbO2 was rarely studied and not well-understood, which was in part due to the overlook of the electrochemistry-driven formation of oxygen vacancy (OV) of PbO2. Herein, we unrevealed the origin of the EOP activity of PbO2 starting from the electrochemical surface state analysis using density functional theory (DFT) calculations, activity analysis, and catalytic volcano modeling. Interestingly, we found that under experimental EOP potential (i.e., a potential around 2.2 V vs. reversible hydrogen electrode), OV can still be generated easily on PbO2 surfaces. Our subsequent kinetic and thermodynamic analyses show that these OV sites on PbO2 surfaces are highly active for the EOP reaction through an interesting atomic oxygen (O*)-O2 coupled mechanism. In particular, rutile PbO2(101) with the "in-situ" generated OV exhibited superior EOP activities, outperforming (111) and(110). Finally, by catalytic modeling, we found that PbO2 is close to the theoretical optimum of the reaction, suggesting a superior EOP performance of rutile PbO2. All these analyses are in good agreement with experimental observations.

Advanced Insights on MXenes: Categories, Properties, Synthesis, and Applications in Alkali Metal Ion Batteries.

The development and optimization of promising anode material for next-generation alkali metal ion batteries are significant for clean energy evolution. 2D MXenes have drawn extensive attention in electrochemical energy storage applications, due to their multiple advantages including excellent conductivity, robust mechanical properties, hydrophilicity of its functional terminations, and outstanding electrochemical storage capability. In this review, the categories, properties, and synthesis methods of MXenes are first outlined. Furthermore, the latest research and progress of MXenes and their composites in alkali metal ion storage are also summarized comprehensively. A special emphasis is placed on MXenes and their hybrids, ranging from material design and fabrication to fundamental understanding of the alkali ion storage mechanisms to battery performance optimization strategies. Lastly, the challenges and personal perspectives of the future research of MXenes and their composites for energy storage are presented.

Antimony Trisulfide with Graphene Oxide Coated Titania Nanotube Arrays as Anode Material for Lithium-ion Batteries

Antimony Trisulfide with Graphene Oxide Coated Titania Nanotube Arrays as Anode Material for Lithium-ion Batteries

Core Shell Structured Silica/Porous Carbon Composite as an Efficient Anode for Lithium Ion Batteries

Si‐based materials are taken into consideration as suitable anode materials for lithium‐ion (Li‐ion) batteries due to their high specific capacity. However, their cycle life is limited due to high volumetric changes during discharging and charging in Li‐ion battery (LIB). Silica (SiO2) is abundantly present in nature, but standalone delivers moderate Li storage capacity. Commercially, graphite is considered as efficient anode in LIB. The current research focuses on improving the performance of silica as anode material to achieve the best specific capacity of LIBs. Herein, the core‐shell‐structured silica/porous carbon composite (50:50, wt%) is synthesized using a hydrothermal method. The shell of porous carbon not only covers the core silica but also provides a very high surface area of ≈1057 m2 g−1 to the composite. The synthesized silica/porous carbon composite acts as an active anode material in Li‐ion half‐cell, which shows the best specific capacity of ≈642 mAh g−1 at 700 cycles at 100 mA g−1 current density and a high capacity retention of ≈97%. The porous carbon on silica helps in the uniform percolation of the electrolyte. It also provides a conducting path to the electrons and further reduces Li‐ion diffusion time by producing more active sites. The shell of porous carbon on core‐silica helps to suppress the volumetric changes that happen during the lithiation and de‐lithiation process. Due to these advantages, the core‐shell‐structured silica/porous carbon composite anode shows consistent and stable cycling performance over large number of cycles.

Correction: Enhanced cycle performance of Li ion battery by graphene sheets covering with SnO@SnO2 anode materials

Correction: Enhanced cycle performance of Li ion battery by graphene sheets covering with SnO@SnO2 anode materials

Enhancement Mechanism of the Difference of Hydrophobicity between Anode and Cathode Active Materials from Spent Lithium-Ion Battery Using Plasma Modification

Enhancement Mechanism of the Difference of Hydrophobicity between Anode and Cathode Active Materials from Spent Lithium-Ion Battery Using Plasma Modification

Boosting potassium and sodium-ion storage performance by in-situ self-assembly of a Co-based π-d conjugated coordination polymer on graphene nanosheets

To obtain anode materials with good electrochemical performances in both potassium ion batteries (PIBs) and sodium-ion batteries (SIBs), a Co-based π-d conjugated coordination polymer (Co-HHTP) is in-situ assembled on graphene (G) nanosheets using a facile one-step solvothermal method. The resulting Co-HHTP/G composite shows improved electrochemical performances over pure Co-HHTP. After 300 cycles of using as an anode of PIBs/SIBs for the first time, the reversible specific capacity of the Co-HHTP/G composite is found to be 381/277 mAh g−1 at 100 mA g−1. After undergoing 500 cycles at 1000 mA g−1, the material's reversible specific capacities remain at 234/164 mAh g−1 for PIBs/SIBs. The improved performances of the Co-HHTP/G composite electrode are due to the incorporation of graphene. This incorporation not only reduces structural stacking and promotes active site utilization, but also increases electrical conductivity and structural stability. According to the ex-situ X-ray photoelectron spectrometer (XPS) spectra, the Co-HHTP/G's energy storage mechanism throughout the process of potassisation/depotassisation is found to be linked to the aromatic rings presented in the organic ligands.

Advanced Electrode Materials based on Brownmillerite Calcium Ferrite for Li‐ion Batteries

Iron‐based materials are considered potential anode materials for lithium‐ion batteries thanks to their low cost, abundancy, non‐flammability, good safety, environmental benignity, and high specific capacity. Here, a series of calcium iron oxides materials having brownmillerite structure (i.e., Ca2Fe2‐xMxO5, where M=Mn, Ni and Cu and x=0 and 0.1) has been extensively studied for their use as conversion anodes in lithium cell. In particular, a mechanochemical approach has been used either to synthesize the samples and to prepare electrodes for the tests in lithium cell. Ca2Fe2O5 based electrodes proved excellent performance in lithium cell, approaching the theoretical capacity and being stable upon prolonged cycling (529 mAh g‐1 at C/10 and a capacity retention of 81 % after 100 cycles). Through the use of ex‐situ diffraction measurements, we have analyzed the conversion mechanism and proved the partial reversibility of its electrochemical reaction. Also, the incorporation of dopants into the structure of calcium iron oxide resulted in further improvement of its electrochemical performance as is the case of Mn doped sample that show a considerable specific capacity of 567 mAh g‐1 and the capacity retention is almost 99 % after 100 cycles.