High-capacity Anode Research Articles

Synergy of Artificial SEI and Electrolyte Additive for Improved Performance of Silicon Electrodes in Li-Ion Batteries.

Maintaining the electrochemically and mechanically stable solid electrolyte interphase (SEI) is of highest importance for the performance of high-capacity anode materials such as silicon (Si). Applying flexible Li-ion permeable coatings to the electrode surface using molecular layer deposition (MLD) offers a strategy to improve the properties of the SEI and greatly contributes to an increase in the cycle life and capacity retention of Si electrodes. In this study, the long-term cycling of Si electrodes with an MLD alucone coating is investigated in the context of more stable SEI formation. When the joined strategy introducing both MLD coating and anFEC electrolyte additive was realized, high performance of Si anodes was achieved, capable of delivering more than 1500 mAh g-1 even after 400 cycles. The reason for the significantly improved longevity is the ability of the alucone layer to react with HF present in LiPF6-based electrolytes already under OCV-like conditions, fluorinating most of the available -OH groups in the alucone structure. This reaction not only partially scavenges hydrofluoric acid but also does not disturb the confining effect of alucone-like fluorinated artificial SEI. This study shows the significance of searching for synergetic solutions, such as a combination of electrode surface modification and electrolyte composition, for maximizing the capacity retention of Si as an active material or as a capacity-enhancing additive to graphite electrodes, and as well can be applied to other high-energy battery materials with large volume changes during cycling.

A versatile opened hollow carbon sphere with highly loaded antimony alloy for ultra-stable potassium-ion storage

Carbon materials meet the stringent practical requirements for anodes for potassium-ion batteries (PIBs) due to their abundance and chemical stability. The major issue of carbon-based anodes is the low specific capacity and poor cyclic stability. Equally importantly, scalable synthesis approaches for electrodes are highly desired for the future application in large-scale energy storage systems. Herein, we developed a novel composite of Sb encapsulated in N/P co-doped opened hollow carbon spheres (N/POHCs) with high Sb loading through a simple carbonization and subsequent impregnation process. Beneficial from the virtue of abundant pyridinic-N−P bonding and opened hollow spherical structure advantages, N/POHCs exhibit much lower diffusion barrier than that of pure carbon, prominent Sb carrier capability, as well as the extraordinary resistance to volume expansion. The resulting Sb@N/POHCs composite delivers a high specific capacity of 533.3 mAh g−1 at 0.1 A g−1 with an initial Coulombic efficiency of 83 %, and can maintain a specific capacity of 345 mAh g−1 at 1 A g−1 after 4000 cycles. This work provides rational structure design with universal carrier capability of active materials to achieve high-capacity and long cycle life anode for advanced PIBs accompanied by the potential for large-scale production.

Exploring Mo2B MBene as a high-capacity anode material for multi-valent metal-ion batteries: Insights from first-principles calculations

A novel class of 2-dimensional (2D) materials, known as MBenes, has recently been proposed as a promising candidate for electrode applications in metal-ion batteries due to their high conductivity and rich chemistry. In this study, we present a computational investigation into the potential of Mo2B MBene as an anode material for Na-, Mg-, and Al-ion batteries. Using density functional theory (DFT) calculations, we examine the structural, electronic, and electrochemical properties of both H- and T-type configurations of Mo2B. Our findings reveal that Mo2B exhibits metallic behavior and excellent metal adsorption characteristics, with Al exhibiting the strongest binding affinity, followed by Mg and Na. This strong binding, especially with Al, although results in higher diffusion barriers, it enhances layer adsorption leading to increased theoretical capacity. The calculated maximum capacities are significant, with Al (1323 mAh g−1) showing the highest capacity, followed by Mg (923 mAh g−1) and Na (216 mAh g−1). Additionally, the open-circuit voltage (OCV) for all metals ranges between 0.1 and 1.0 V, suggesting the suitability of Mo2B MBene as an anode material that minimizes dendrite formation risks. These results indicate the potential of Mo2B for high-performance multi-valence ion batteries, with particular promise for Al-ion batteries due to their superior capacity. Furthermore, we propose that strain engineering could optimize Mo2B for enhanced performance in Na-ion batteries. Overall, this study suggests Mo2B MBene as a highly promising anode material for next-generation metal-ion batteries, offering significant advantages in terms of capacity, voltage, and safety. Our findings provide insights that could be used for further experimental design of Mo2B-based anodes for energy storage technologies.

3D Tunnel Copper Tetrathiovanadate Nanocube Cathode Achieving Ultrafast Magnesium Storage Reactions through a Charge Delocalization and Displacement Mechanism.

Rechargeable magnesium batteries are attractive candidates for large-scale energy storage applications because of the low cost and high safety, but the scarcity and inferior performance of the cathode materials are hindering the development. In the present study, a kind of copper tetrathiovanadate (Cu3VS4) cathode is designed and developed with a comprehensive consideration of the chemical and electronic structures. The vanadium and sulfur atoms form chemical bonds with high covalent proportion, facilitating electron delocalization via the vanadium-sulfur bonds. This reduces the interaction with the bivalent magnesium cation and induces the coredox of vanadium and sulfur. The crystal structure of Cu3VS4 has interlaced 3D tunnels for solid-state magnesium cation transport. The Cu3VS4 cathode shows a high capacity of 350 mA h g-1 at 100 mA g-1, an outstanding rate performance of 67 mA h g-1 at 10 A g-1, and stable cycling for 1000 cycles at 5 A g-1 without obvious capacity fading. Prominently, a high areal mass load of 3.5 mg cm-2 could be achieved without obvious rate capability decay, which is quite favorable to pair with the high-capacity magnesium metal anode in practical application. The mechanism investigation and theoretical computation demonstrate that Cu3VS4 undergoes first a magnesium intercalation and then a displacement reaction, during which the crystal structure is maintained, assisting the reaction reversibility and cycling stability. All the copper, vanadium, and sulfur elements experience redox and contribute to the high capacity. Moreover, the weakened interaction with magnesium cations, well-kept 3D cation transport tunnels, and high electronic conductivity result in the superior rate performance and high areal active material loading. The present study develops a high-performance cathode for rechargeable magnesium batteries and reveal the design principle based on both of chemical and electronic structures.

A Molten Alkali Approach to Tailor Hydroxyl Groups of Hexaazatrinaphthalene Toward High-Capacity and Low-Potential Anode of Aqueous Proton Batteries.

Hexaazatrinaphthalene (HATN) has attracted a lot of attention in aqueous proton batteries (APBs). However, its redox potential as an anode is insufficiently negative. The introduction of electron-donating substituent groups, such as hydroxyl groups, is considered as a good approach to reduce the redox potential of HATN. Nevertheless, manufacturing hydroxyl-substituted HATN (HATN-OH) requires either expensive precursors or multi-step process, limiting their research. Herein, a straightforward strategy is proposed to synthesize HATN-OH based on the nucleophilic substitution reaction of halogenated HATN in a molten alkali. The redox potential of 1,2,7,8,13,14-hexahydroxy-5,6,11,12,17,18-hexaazatrinaphthalene (34-HATN-6OH) electrode may be lowered by 0.15V in comparison to HATN, and exhibits a high specific capacity, low redox potential, remarkable rate capability, and outstanding long-term cycling performance. The electrochemical redox kinetics is significantly enhanced owing to the formation of rapid proton transport channels created by intermolecular hydrogen bond network. The assembled MnO2||34-HATN-6OH full battery delivers a high discharge voltage (1.16V) and cycling stability (74% capacity retention after 5000 cycles). This study provides a general cost-effective molten alkali approach for the synthesis of hydroxyl-substituted conjugated small molecules from their halogenated counterparts and further enriches the regulation means of electro-chemical performances of organic electrodes for enabling high-capacity and high-voltage APBs.

A single-ion transport interfacial layer for solid-state lithium batteries

All-solid-state batteries possess several advantages including high safety, flexibility to use high-capacity metal anodes and are projected to be the next generation energy storage devices. Garnet-type cubic Li7La3Zr2O12 (LLZO) solid electrolyte is of particular interest due to its high ionic conductivity under ambient conditions and compatibility with Li metal. However, large electrode/electrolyte interfacial resistance constraints their development. Herein, the use of a highly lithium ion conducting dilithium phthalocyanine (Li2Pc) in ionic liquid as an interlayer is proposed to effectively suppress the high impedance at the interface thus improving the electrode-electrolyte contact. Fast Li+ mobility and high dielectric constant of dilithium phthalocyanine enhance the kinetics of Li+ transport across the interface. A significant reduction in overpotential and very stable stripping/plating cycling are observed in lithium symmetric cells upon introducing Li2Pc interlayer as compared to the use of bare tantalum doped lithium lanthanum zirconium oxide (LLZTO) electrolyte. Cells comprising interlayer-modified Li|LLZTO|LiFePO4 show high capacity with excellent cycling and rate capability. The performance of full cells using lithiated graphite and lithium titanate anodes has also been evaluated. This study presents a promising application of garnet electrolytes towards the advancement of solid-state lithium batteries.

High-Capacity Anode for Sodium-Ion Batteries Using Hard Carbons Derived from Polyurea-Cross-Linked Silica Xerogel Powders

High-Capacity Anode for Sodium-Ion Batteries Using Hard Carbons Derived from Polyurea-Cross-Linked Silica Xerogel Powders

Delithiation-accelerating and self-healing strategies realizes high-capacity and high-rate black phosphorus anode in wide temperature range

Black phosphorus (BP) anode with high capacity (2596 mAh g−1) and suitable lithiation potential (0.7 V vs. Li+/Li) is an ideal candidate for high-energy-density and high-safety lithium-ion batteries, however, the pratical implementation is greatly limited by its slow reaction kinetics and huge volume expansion. Here, inspired by nature, liquid metal (LM) is explored as a self-heal agent, which can well stabilize the BP anode through buffering the volumetric expansion and re-activating “dead P and LixP”. Moreover, LM also acts as a good catalyst, which can adjust Li ion concentration and reduce the activation energy of delithiation reaction, thus prolonging the cycling life. Therefore, the LM modified BP/graphite (G) composite delivers an excellent high-rate performance of 1123 mAh g−1 at 4 C with 80.0% capacity retention after 200 cycles, a superior wide-temperature performance of 1547.5 mAh g−1 and 569.0 mAh g−1 at 50 oC and −20 oC, respectively.

Unraveling the enhanced sodium-storage mechanism in a strongly bonded 2D honeycomb borophene/boron phosphide heterostructure

The growing modern demand for battery capacity is driving the development of high-capacity metal-ion battery anodes for future energy storage. Two-dimensional (2D) material-based heterostructures have shown advantages as alternative anodes due to their enhanced adsorption capacity. The lightweight nature of honeycomb borophene (HB) is beneficial for serving as a high-capacity anode but is constrained by structural instability arising from electron deficiency. In this study, using first-principles calculations, we propose a HB/boron phosphide (BP) heterostructure as an anode for both lithium-ion batteries and sodium-ion batteries (SIBs). The heterostructure engineering not only stabilizes the HB structure but also leads to a bonding heterostructure instead of common van der Walls type. The HB/BP demonstrates robust structural stability and reversibility when multiple ions are stored. In addition, the HB/BP offers stable storage sites and low diffusion barriers for lithium (0.31 eV) and sodium (0.28 eV), indicating rapid charging–discharging performance. Notably, the predicted maximum sodium storage capacity reaches 2402 mAh/g, surpassing that of the constituent monolayers and most 2D heterostructures. The underlying mechanism for high storage capacity is elucidated through detailed charge image model analysis, offering atomistic-scale insights for constructing high-capacity anodes. All results suggest that the presented HB/BP is a promising anode candidate for SIBs and opens an avenue for stabilizing HB in energy storage.

Advancements in Lithium-Ion Battery Technology

Lithium-ion (Li-ion) batteries are at the forefront of modern energy storage technologies due to their high energy density, long cycle life, and relatively low self-discharge rate. Recent advancements in materials science, battery management systems, and fabrication techniques have significantly improved the performance, safety, and sustainability of Li-ion batteries. This paper explores the latest developments in lithium-ion technology, including high-capacity anode and cathode materials, solid-state electrolytes, and next-generation designs, while also addressing the challenges and future directions for research and application.

A cubic perovskite fluoride anode with the surface conversion reactions dominated mechanism for advanced lithium-ion batteries.

Perovskite fluorides are attractive anode materials for lithium-ion batteries (LIBs) because of their three-dimensional diffusion channels and robust structures, which is advantageous for the rapid transmission of lithium ions. Unfortunately, the wide band gap results in poor electronic conductivity, which limits their further development and application. Herein, the cubic perovskite iron fluoride (KFeF3, KFF) nanocrystals (~100 nm) are synthesized by a one-step solvothermal strategy. Thanks to the good electrical conductivity of carbon nanotubes (CNTs), the overall electrochemical performance of composite anode material (KFF-CNTs) has been significantly improved. In particular, the KFF-CNTs delives a high specific capacity (363.8 mAh g-1), good rate performance (131.6 mAh g-1 at 3.2 A g-1), and superior cycle stability (500 cycles). Noted that the surface conversion reactions play a dominant role in the electrochemical process of KFF-CNTs, together with the stable octahedral perovskite structure and nanoscale particle sizes achieving high ion diffusion coefficients. Furthermore, the specific lithium storage mechanism of KFF has explored by the distribution of relaxation times (DRT) technology. This work opens up a new way for developing cubic perovskite fluorides as high-capacity and robust anode materials for LIBs.

Enhancing Tin Dioxide Anode Performance by Narrowing the Potential Range and Optimizing Electrolytes

Tin dioxide (SnO2) is a low-cost and high-capacity anode material for lithium-ion batteries, but the fast capacity fading significantly limits its practical applications. Current research efforts have focused on preparing sophisticated composite structures or optimizing functional binders, both of which increase material manufacturing costs. Herein, we utilize pristine and commercially available SnO2 nanopowders and enhance their cycling performance by simply narrowing the potential range and optimizing electrolytes. Specifically, a narrower potential range (0–1 V) mitigates the capacity fading associated with the conversion reaction, whereas an ether-based electrolyte further suppresses the volume expansion related to the alloy reaction. Consequently, this SnO2 anode delivers a promising battery performance, with a high capacity of ~650 mAhg−1 and stable cycling for 100 cycles. Our work provides an alternative approach to developing high-capacity and long-cycling metal oxide anode materials.

Elucidation on Abnormal Capacity Increase in SiO2@C Core-Shell Nanospheres Anode for Lithium-Ion Battery.

An abnormal capacity increase stage has been observed in nanostructured SiO2 after the initial capacity drop stage. To investigate the Li+ storage kinetic mechanism for each stage, SiO2@C core-shell nanospheres with a total diameter of ∼108 to 170 nm but an adjustable C shell thickness of ∼4 to 31 nm have been fabricated. First, the existence form and specific content of SiO2 nanoparticles with a size of ∼6-10 nm, which are embedded in the outer C shell of SiO2@C core-shell nanospheres, were confirmed by SEM, TEM, BET, and TGA, respectively. It was found that the initial stage for capacity drop happens at 15-43 cycles and is followed by an enhancement stage, which presents an increase of ∼120 to 180% in capacity relative to the lowest capacity value during cycling. Among them, the sample of P-1 with a diameter of 109 nm for the SiO2 core and thickness of 31 nm for the C shell delivers the highest specific capacity of 1060 mAh/g at 100 mA/g and a capacity increase rate of ∼180% through 300 cycles. XPS analysis for the delithiation process indicates that the capacity drop and increase stage involves the partial oxidation of Li silicate, which is correlated to the formation of Li2Si2O5. Our study can be used to explain the mechanism of the abnormal capacity increase phenomenon for the SiO2 anode and provide a high-capacity anode material for LIB application.

High-Capacity Zinc Anode Enabled by a Recyclable Biomass Bamboo Membrane Separator.

Aqueous zinc ion batteries have gained attention as viable energy storage systems, yet the occurrence of detrimental side reactions and Zn dendrite formation undermines the efficiency of Zn anodes. Controlling water activity have proven to be an effective strategy in mitigating these challenges. However, strategies such as electrolyte design and electrode protection layer show weakness to varying degrees. Here, a new oxygen-functionalized biomass bamboo membrane separator (denoted as BM) is proposed to restrain the activity of water molecules. This BM separator features a unique, multi-tiered 2D interlayer that facilitates rapid ion diffusion. Additionally, the oxygen functional groups of the BM separator can form hydrogen bonds with water molecules, effectively transforming water molecules from a free state to a bound state. Consequently, the Zn/Zn asymmetric coin cell using BM can work at the ultrahigh rate and capacity of 30 mA cm-2 and 30mAhcm-2 for more than 80h while its counterparts using glass fibercan barely work. Moreover, full cells using BM separator exhibited a capacity retention of 89.7% after 1000 cycles at 10Ag-1. This study reveals the important influence of water-limited activity on Zn anode protection and provides an avenue for the design of novel separator.

In situ multilevel covalent crosslinking binder with high ionic conductivity for high-performance Si anodes

Silicon (Si) anode has emerged as a promising material for high-energy-density lithium-ion batteries (LIBs), thanks to its high theoretical capacity. However, the commercial application of Si anodes is hindered by inadequate cycling performance and poor interfacial stability, stemming from unfavorable stress conditions. In this study, a multiple crosslinking binder with high ionic conductivity is proposed combining high mechanical strength and high adhesion to current collector and active Si particles by coupling poly(acrylic acid), polyvinyl alcohol, and polyethylene glycol. The designed polymer binder not only efficiently dissipates the inner stress with its multiple crosslinked networks, but also establishes a fast lithium-ion conduction pathway to facilitate the electrode reaction kinetic. The resultant Si anode using the designed binder exhibits significantly improved cycling stability and superior rate performance. This work presents a straightforward yet highly effective method to alleviate the detrimental stress incurred by high-capacity anodes in high-energy LIBs.

Oxygen vacancy modulated Ti2Nb10O29 anodes for high-rate lithium storage

Ti2Nb10O29 (TNO) is a prospective anode for lithium-ion batteries (LIBs) because of its high theoretical capacity, high energy density, and safer operating voltage. However, the lower conductivity and slower lithium-ion diffusion characteristic lead to performance degradation and accelerated capacity degradation. In this work, we developed a novel and simple urea-assisted heat treatment method to enrich oxygen vacancies in TNO anodes. Oxygen vacancy introduction leads to the formation of Ti3+ and Nb4+ and the optimization of electronic structure, which provide more active sites for ion insertion and accelerate electron transport and migration. The optimized sample (TNO-M) demonstrates excellent high-rate capacity and cyclic stability. Specifically, the reversible capacity is 155.4 mAh/g at 10C. A capacity retention ratio of 97.87 % can be maintained after 200 cycles at 1C. Even after 500 cycles at 5C, TNO-M can still deliver a high capacity of 156.4 mAh/g. The strategy of developing high-capacity and high-rate anodes provides a new inspiration for the applications of fast charging of energy-dense LIBs.

Defect-driven ion storage on hexagonal boron nitride for fire-safe and high-performance lithium-ion batteries

The mass market adoption of electric vehicles has increased the risk of safety concerns, such as overheating and flammability. Rational design of fire-safe and high-capacity anodes with thermal tolerance, capable of fast-charging and long cycle-life, is crucial for the development of next generation Li-ion batteries operating under extreme conditions. Here we report a defect engineered hexagonal boron nitride (hBN) anode to mediate the safety dilemma. We demonstrate that the defects generated via cryomilling catalyze the reversible LiF formation and enable the pseudocapacitive type Li-ion storage on hBN. The non-flammability and excellent thermal tolerance of hBN allows high specific capacity (880 mAh/g @ 25 mA/g), rate performance (480 mAh/g @ 5 A/g) and stable cycling (5000 cycles) at 60 °C. The Li-ion full-cell with the defective hBN anode and the conventional cathode (LiNiMnCoO2) delivers significantly higher energy (400 Wh kg−1) and power density (1 kW kg−1) when compared to graphite/LiNiMnCoO2 full-cells (121 Wh kg−1 and 250 W kg−1). First-principles calculations confirm that nitrogen antisite (NBVN) defects are responsible for the electrochemical activation of otherwise inactive hBN. The strategy of defect-induced electrochemical activation opens up new avenues in the design of high-performance electrode materials for numerous secondary batteries.

Electrochemical sodium storage properties in monolayer VOPO4: A density functional theory prediction

The unique structural properties of two-dimensional materials make them promising for energy storage applications. This work theoretically predicts for the first time that Monolayer VOPO4 (MNL VOPO4), exfoliated from the delithiated phase of tetragonal LiVOPO4, is stable at room temperature, exhibiting excellent thermodynamic and kinetic stability, thus making it a promising high-capacity anode material for sodium-ion batteries (SIBs). Compared to bulk VOPO4, the monolayer structure significantly reduces the sodium ion migration energy barrier from 1.006 to 0.0795 eV, thereby markedly enhancing sodium ion migration kinetics. MNL VOPO4 can adsorb up to 32 sodium ions, corresponding to a theoretical capacity of 634.88 mA h g−1 and an energy density of 895.18 Wh kg−1. Furthermore, the excellent structural stability of MNL VOPO4 favors its cycling performance during charge and discharge processes. This work provides theoretical insights for better utilizing and developing multi-atomic phosphate compounds as electrode materials for secondary batteries.

Hard carbon/graphene microfibers as a superior anode material for sodium-ion batteries

Hard carbon is one of the most promising anode materials for sodium-ion batteries (SIBs). However, it still suffers from low specific capacity and poor rate capability, which impede its practical application. Herein, one-dimensional hard carbon/graphene microfibers are synthesized by encapsulating hard carbon particles in graphene nanosheet using a wet-spinning technique followed by pyrolysis treatment. Benefiting from the unique structure, when used as the anode material for SIBs, the as-obtained hard carbon/graphene microfibers not only exhibit a high reversible capacity of 321 mAh g−1 at 0.1 C but also deliver long cycling stability and excellent rate capability, maintaining its capacity as 203 mAh g−1 even after 350 cycles at 1 C. In addition, the sodium storage mechanism of the as-prepared hard carbon/graphene microfibers is investigated by in-situ Raman technique. Moreover, a full cell adopting the hybrid microfiber as the anode and Na3V2(PO4)3 as the cathode exhibits high specific capacities of 291 mAh g−1 and 204 mAh g−1 at 0.2 C and 4 C (vs. anode), respectively. This work provides a sustainable and cost-effective strategy for the synthesis of high-capacity and stable hard carbon anode materials.

Enhancing interfacial properties on Silicon-Graphite anode by alkenyl-functionalization of fluorinated cyclotriphosphazene in high-voltage lithium-ion batteries

The pursuit for high energy density in lithium-ion batteries has driven the blended adoption of high-voltage cathode and high-capacity Silicon-based anode. Unfortunately, the carbonate-based electrolytes fail to be compatible with these electrode materials and the flammable nature of linear carbonates poses safety hazards to electrolytes. Fluorinated cyclotriphosphazenes can enhance the safety level of electrolytes and possesses the function of high-voltage additives. However, it is difficult to directly employ fluorinated cyclotriphosphazenes in high-voltage lithium-ion batteries containing Silicon-based anode. In this work, an alkenyl-functionalized cyclotriphosphazene- (3-butenoxy)pentafluorocyclotriphosphazene is constructed to enhance the compatibility between electrolytes and Silicon-Graphite anode. The mixed use of (3-butenoxy)pentafluorocyclotriphosphazene and (ethoxy)pentafluorocyclotriphosphazene not only makes electrolytes nonflammable but also renders preeminent performances to 4.45 V LiCoO2/Silicon-Graphite pouch cells at 25 °C. The capacity retention of the cell at 1C after 150 cycles surpasses 80 %, and the discharge capacity ratio of 8C/1C reaches around 53 %. With scanning electron microscopy and X-ray photoelectron spectroscopy technique, it is verified that the mixed flame retardant can build a robust interface film on the anode, which handles the adverse effects caused by the volume expansion of Silicon-Graphite.