Materials Based on Antimony and Bismuth for Sodium Storage

Bismuth-Nanoparticles-Embedded Porous Carbon Derived from Seed Husks as High-Performance for Anode Energy Electrode

In energy application technology, the anode part of the electrode is typically composed of carbon-coated materials that exhibit excellent electrochemical performance. The carbon-coated electrodes facilitate electrochemical reactions involving the fuel and the oxidant. Energy electrodes are used in stationary power plants to generate electricity for the grid. These large-scale installations are known as distributed generation systems and contribute to grid stability and reliability. Understanding the practical applications of energy materials remains a significant hurdle in the way of commercialization. An anode electrode has one key limitation, specifically with alloy-type candidates, as they tend to exhibit rapid capacity degradation during cycling due to volume expansion. Herein, biomass-derived carbon from sunflowers (seeds husks) via pyrolysis and then bismuth nanoparticles are treated with carbon via a simple wet-chemical method. The electrode Bi@C offers several structural advantages, such as high capacity, good cycling stability, and exceptional capability at the current rate of 500 mA g-1, delivering a capacity of 731.8 mAh g-1 for 200 cycles. The biomass-derived carbon coating protects the bismuth nanoparticles and contributes to enhanced electronic conductivity. Additionally, we anticipate the use of low-cost biomass with hybrid composition has the potential to foster environment-friendly practices in the development of next-generation advanced fuel cell technology.

Molten salt-assisted synthesis of bismuth nanosheets with long-term cyclability at high rates for sodium-ion batteries

Bismuth is a promising anode material for sodium-ion batteries (SIBs) due to its high capacity and suitable working potential. However, the large volume change during alloying/dealloying would lead to poor cycling performance. Herein, we have constructed a 3D hierarchical structure assembled by bismuth nanosheets, addressing the challenges of fast kinetics, and providing efficient stress and strain relief room. The uniform bismuth nanosheets are prepared via a molten salt-assisted aluminum thermal reduction method. Compared with the commercial bismuth powder, the bismuth nanosheets present a larger specific surface area and interlayer spacing, which is beneficial for sodium ion insertion and release. As a result, the bismuth nanosheet anode presents excellent sodium storage properties with an ultralong cycle life of 6500 cycles at a high current density of 10 A g-1, and an excellent capacity retention of 87% at an ultrahigh current rate of 30 A g-1. Moreover, the full SIBs that paired with the Na3V2(PO4)3/rGO cathode exhibited excellent performance. This work not only presents a novel strategy for preparing bismuth nanosheets with significantly increased interlayer spacing but also offers a straightforward synthesis method utilizing low-cost precursors. Furthermore, the outstanding performance demonstrated by these nanosheets indicates their potential for various practical applications.

Novel Preoxidation-Assisted Mechanism to Preciously Form and Disperse Bi2O3 Nanodots in Carbon Nanofibers for Ultralong-Life and High-Rate Sodium Storage

Metal oxides, as promising electrode materials for sodium-ion batteries, usually need to be formed by exposure to oxygen, which usually thermally corrodes the carbon material with which they are compounded, reducing their flexibility and electrical conductivity. Herein, we present for the first time a preoxidation-assisted mechanism to prepare bismuth oxide and carbon nanofibers (Bi₂O₃@C-NFs) by electrospinning, using Bi₂S₃ nanorods as multifunctional templates. The bismuth could be oxidized by C═O bonds formed through the cyclization reaction in the high-temperature calcination process, effectively avoiding thermal corrosion of carbon in oxygen atmosphere at high temperature. More importantly, the uniformly distributed Bi₂O₃ nanodots and longitudinal tunnels are formed inside the S- and N-doped carbon nanofibers with the continuous diffusion of Bi generated from the decomposition of Bi₂S₃ nanorods and the conversion to Bi─O bonds with C═O bonds being broken. Benefiting from the structural and composition merits arising from preoxidation, Bi₂O₃@C-NFs self-supporting anodes show high specific capacity (439 mAh g^-1 at 0.05 A g^-1), superior rate performance (243 mAh g^-1 at a current density of 20 A g^-1), and outstanding cycling stability (211 mAh g^-1 after 2000 cycles at 5 A g^-1). The effective combination of the well-established electrospinning technology and the preoxidation assisted mechanism provides a new way for the preparation of metal oxide and carbon composites.

Fully Active Bimetallic Phosphide Zn0.5Ge0.5P: A Novel High-Performance Anode for Na-Ion Batteries Coupled with Diglyme-Based Electrolyte

Metal phosphides are promising candidates for sodium-ion battery (SIB) anode owing to their large capacities with suitable redox potential, while the reversibility and rate performances are limited due to some electrochemically inactive transition-metal components and sluggish reaction kinetics. Here, we report a fully active bimetallic phosphide Zn_0.5Ge_0.5P anode and its composite (Zn_0.5Ge_0.5P-C) with excellent performance attributed to the Zn, Ge, and P components exerting their respective Na-storage merit in a cation-disordered structure. During Na insertion, Zn_0.5Ge_0.5P undergoes an alloying-type reaction, along with the generation of NaP, Na₃P, NaGe, and NaZn₁₃ phases, and the uniform distribution of these phases ensures the electrochemical reversibility during desodiation. Based on this reaction mechanism, excellent electrochemical properties such as a high reversible capacity of 595 mAh g^-1 and an ultrafast charge-discharge capability of 377.8 mAh g^-1 at 50C for 500 stable cycles were achieved within the Zn_0.5Ge_0.5P-C composite in a diglyme-based electrolyte. This work reveals the Na-storage reaction mechanism within Zn_0.5Ge_0.5P and offers a new perspective on designing high-performance anodes.

Structurally Durable Bimetallic Alloy Anodes Enabled by Compositional Gradients

Metals such as Sb and Bi are important anode materials for sodium-ion batteries because they feature a large capacity and low reaction potential. However, the accumulation of stress and strain upon sodium storage leads to the formation of cracks and fractures, resulting in electrode failure upon extended cycling. In this work, the design and construction of Bi_x Sb_1-x bimetallic alloy films with a compositional gradient to mitigate the intrinsic structural instability is reported. In the gradient film, the top is rich in Sb, contributing to the capacity, while the bottom is rich in Bi, helping to reduce the stress in the interphase between the film and the substrate. Significantly, this gradient film affords a high reversible capacity of ≈500 mAh g^-1 and sustains 82% of the initial capacity after 1000 cycles at 2 C, drastically outperforming the solid-solution counterpart and many recently reported alloy anodes. Such a gradient design can open up the possibilities to engineering high-capacity anode materials that are structurally unstable due to the huge volume variation upon energy storage.

Chemistry, Functionalization, and Applications of Recent Monoelemental Two-Dimensional Materials and Their Heterostructures

The past decades have witnessed a rapid expansion in investigations of two-dimensional (2D) monoelemental materials (Xenes), which are promising materials in various fields, including applications in optoelectronic devices, biomedicine, catalysis, and energy storage. Apart from graphene and phosphorene, recently emerging 2D Xenes, specifically graphdiyne, borophene, arsenene, antimonene, bismuthene, and tellurene, have attracted considerable interest due to their unique optical, electrical, and catalytic properties, endowing them a broader range of intriguing applications. In this review, the structures and properties of these emerging Xenes are summarized based on theoretical and experimental results. The synthetic approaches for their fabrication, mainly bottom-up and top-down, are presented. Surface modification strategies are also shown. The wide applications of these emerging Xenes in nonlinear optical devices, optoelectronics, catalysis, biomedicine, and energy application are further discussed. Finally, this review concludes with an assessment of the current status, a description of existing scientific and application challenges, and a discussion of possible directions to advance this fertile field.

Metal-Organic Framework Derived Ultrafine Sb@Porous Carbon Octahedron via In Situ Substitution for High-Performance Sodium-Ion Batteries

Alloying-type anode materials are regarded as promising alternatives beyond intercalation-type carbonaceous materials for sodium storage owing to the high specific capacities. The rapid capacity decay arising from the huge volume change during Na⁺-ion insertion/extraction, however, impedes the practical application. Herein, we report an ultrafine antimony embedded in a porous carbon nanocomposite (Sb@PC) synthesized via facile in situ substitution of the Cu nanoparticles in a metal-organic framework (MOF)-derived octahedron carbon framework for sodium storage. The Sb@PC composite displays an appropriate redox potential (0.5-0.8 V vs Na/Na⁺) and excellent specific capacities of 634.6, 474.5, and 451.9 mAh g^-1 at 0.1, 0.2, and 0.5 A g^-1 after 200, 500, and 250 cycles, respectively. Such superior sodium storage performance is primarily ascribed to the MOF-derived three-dimensional porous carbon framework and ultrafine Sb nanoparticles, which not only provides a penetrating network for rapid transfer of charge carriers but also alleviates the agglomeration and volume expansion of Sb during cycling. Ex situ X-ray diffraction and in situ Raman analysis clearly reveal a five-stage reaction mechanism during sodiation and desodiation and demonstrate the excellent reversibility of Sb@PC for sodium storage. Furthermore, post-mortem analysis reveals that the robust structural integrity of Sb@PC can withstand continuous Na⁺-ion insertion/extraction. This work may provide insight into the effective design of high-capacity alloying-type anode materials for advanced secondary batteries.

Natural Cellulose Substance Based Energy Materials

Natural cellulose substances have been proven to be ideal structural templates and scaffolds for the fabrication of artificial functional materials with designed structures, psychochemical properties and functionalities. They possess unique hierarchically porous network structures with flexible, biocompatible, and environmental characteristics, exhibiting great potentials in the preparation of energy-related materials. This minireview summarizes natural cellulose-based materials that are used in batteries, supercapacitors, photocatalytic hydrogen generation, photoelectrochemical cells, and solar cells. When natural cellulose substances are employed as the structural template or carbon sources of energy materials, the three-dimensional porous interwoven structures are perfectly replicated, leading to the enhanced performances of the resultant materials. Benefiting from the mechanical strengths of natural cellulose substances, wearable, portable, free-standing, and flexible materials for energy storage and conversion are easily obtained by using natural cellulose substances as the substrates.

Pnictogen Semimetal (Sb, Bi)-Based Nanomaterials for Cancer Imaging and Therapy: A Materials Perspective

Innovative multifunctional nanomaterials have attracted tremendous interest in current research by facilitating simultaneous cancer imaging and therapy. Among them, antimony (Sb)- and bismuth (Bi)-based nanoparticles are important species with multifunction to boost cancer theranostic efficacy. Despite the rapid development, the extensive previous work treated Sb- and Bi-based nanoparticles as mutually independent species, and therefore a thorough understanding of their relationship in cancer theranostics was lacking. We propose here that the identical chemical nature of Sb and Bi, being semimetals, provides their derived nanoparticles with inherent multifunction for near-infrared laser-driven and/or X-ray-based cancer imaging and therapy as well as some other imparted functions. An overview of recent progress on Sb- and Bi-based nanoparticles for cancer theranostics is provided to highlight the relationship between chemical nature and multifunction. The understanding of Sb- and Bi-based nanoparticles in this way might shed light on the further design of smart multifunctional nanoparticles for cancer theranostics.

SnO2-Embedded Nanoporous Carbon Electrode with a Reaction-Buffer Space for Stable All-Solid-State Li Ion Batteries

The conventional approach for fabricating all-solid-state batteries has required a highly dense layer of electrode and electrolyte. Their close contact interface is not suitable for alloy- or conversion-based active materials because their large volume change in lithiation/delithiation reactions causes a collapse of the contact interface or reaction limitations under mechanical constriction. In this study, we propose that a SnO₂-embedded porous carbon electrode shows high cyclability and high capacity even at high constraint pressure owing to the nanopores, which work as a buffer space for the large volume change accompanied with SnO₂-Sn conversion reaction and Sn-Li alloying-dealloying reaction. A detailed investigation between structural parameters of the electrode material and charge-discharge properties revealed Li ion conduction in carbon nanopores from a solid electrolyte located outside as well as the optimal conditions to yield high performance. SnO₂-loading (75 wt %) in carbon nanopores, which provides the buffer space corresponding to the inevitable volume expansion by full lithiation, brought out an excellent performance at room temperature superior to that in an organic liquid electrolyte system: a high capacity of 1023 mAh/g-SnO₂ at 50 mA/g, high capacity retention of 97% at 300th cycle at 300 mA/g, and high rate capability with over 75% capacity retention at 1000 against 50 mA/g, whose values are also superior to the system using the organic liquid electrolyte.

Durian-Inspired Design of Bismuth-Antimony Alloy Arrays for Robust Sodium Storage

Sodium-ion batteries have attracted widespread attention for cost-effective and large-scale electric energy storage. However, their practical deployment has been largely retarded by the lack of choice of efficient anode materials featuring large capacity and electrochemical stability and robustness. Herein, we report a durian-inspired design and template-free fabrication of a robust sodium anode based on triangular pyramid arrays of Bi_0.75Sb_0.25 alloy electrodeposited on Cu substrates. The Bi_0.75Sb_0.25 arrays exhibit an appreciable electrochemical robustness for sodium storage, sustaining a reversible capability 335 mAh g^-1 at a high rate of 2.5 A g^-1 and 87% of the initial capacity over 2000 cycles. We further demonstrate the applicability of the Bi_0.75Sb_0.25 array anode in sodium full cells by pairing it with a Na₃V₂(PO₄)₃/C cathode. This full cell achieves a high specific energy of 203 Wh kg^-1 (based on both active electrodes). Such an enhanced performance is attributed to the thorny-durian-like architecture and bimetallic alloy composition. The pyramid tip induces ion enrichment for rapid charge-transfer reaction, while the alloy design reduces the electrode volume swelling for stable Na cycling.

Ultrastable Sodium Storage in MoO3 Nanotube Arrays Enabled by Surface Phosphorylation

Molybdenum trioxide (MoO₃) has been considered as an appealing choice of anode for sodium-ion batteries because of its high theoretical capacity (1117 mA h g^-1). However, the large volume change upon Na⁺ storage results in poor cycling stability and capacity fade of MoO₃. Here, we demonstrate a surface phosphorylation strategy to mitigate the degradation of three-dimensional MoO₃ array electrodes. Such a phosphorylation strategy allows MoO₃ arrays to sustain a capacity of 265 mA h g^-1, or ∼90% of the initial value, at a rate of 2 A g^-1 over 1500 cycles, outperforming most reported MoO₃ electrodes. Moreover, kinetic analysis unveils a capacitance-dominated Na⁺ storage feature of MoO₃ arrays, owing to the enhanced electron mobility imparted by oxygen vacancies that are simultaneously introduced by phosphorylation. Hence, surface phosphorylation might offer new possibilities to bypass multiple materials challenges facing current sodium electrodes.

A Calcium Organic Salt/rGO composite with Low Solubility and High Conductivity as a Sustainable Anode for Sodium-Ion Batteries

Organic electrodes hold great promise for sustainable electrodes in sodium-ion batteries (SIBs) owing to their easy availability from biomass. However, traditional organic electrodes suffer from two inherent problems, high solubility in organic electrolytes and low electronic conductivity. Here, a calcium organic salt, Cabpdc (bpdc=4,4'-biphenyldicarboxylate) was designed and formed into a composite with reduced graphene oxide (rGO) to improve these two problems by a "two-in-one" approach. As expected, the Cabpdc/rGO composite displayed competitive cycle and rate performances as an anode for SIBs. Additionally, all-organic sodium-ion full cells were successfully fabricated combining this anode with a commercial organic cathode, promising applications for sustainable SIBs.

Designed One-Pot Strategy for Dual-Carbon-Protected Na3 V2 (PO4 )3 Hybrid Structure as High-Rate and Ultrastable Cathode for Sodium-Ion Batteries

Sodium-ion batteries have attracted tremendous attention due to their much lower cost and similar working principle compared with lithium-ion batteries, which have been invited great expectation as energy storage devices in grid-level applications. The sodium superionic conductor Na₃ V₂ (PO₄ )₃ has been considered as a promising cathode candidate; however, its intrinsic low electronic conductivity results in poor rate performance and unsatisfactory cycling performance, which severely impedes its potential for practical applications. Herein, we developed a facile one-pot strategy to construct dual carbon-protected hybrid structure composed of carbon coated Na₃ V₂ (PO₄ )₃ nanoparticles embedded with carbon matrix with excellent rate performance, superior cycling stability and ultralong lifespan. Specifically, it can deliver an outstanding rate performance with a 51.5 % capacity retention from 0.5 to 100 C and extraordinary cycling stability of 80.86 % capacity retention after 6000 cycles at the high rate of 20 C. The possible reasons for the enhanced performance could be understood as the synergistic effects of the strengthened robust structure, facilitated charge transfer kinetics, and the mesoporous nature of the Na₃ V₂ (PO₄ )₃ hybrid structure. This work provides a cost-effective strategy to effectively optimize the electrochemical performance of a Na₃ V₂ (PO₄ )₃ cathode, which could contribute to push forward the advance of its practical applications.

Control of SEI Formation for Stable Potassium-Ion Battery Anodes by Bi-MOF-Derived Nanocomposites

Bismuth (Bi)-based electrodes are highly attractive for potassium-ion batteries (PIBs) while suffering from a short cycle life due to the larger diameter of K ion, leading to unstable solid electrolyte interface (SEI) films during continuous potassiation/depotassiation. Herein, we developed novel ultrathin carbon film@carbon nanorods@Bi nanoparticle (UCF@CNs@BiN) materials for the long cycle life anode of PIBs. Bi nanoparticles are uniformly distributed in carbon nanorods, which not only provides a high-speed channel for ion transport but also accommodates the volume change of Bi nanoparticles during continuous potassiation/depotassiation processes. The UCF@CN matrix can direct most SEI film formation on the surface of the carbon film, not on the surface of individual Bi nanoparticles, avoiding the fracture of the matrix. Benefiting from their unique structure, the UCF@CNs@BiN anodes exhibit an outstanding capacity of ∼425 mAh g^-1 at 100 mA g^-1 and a capacity decay of 0.038% per cycle over 600 cycles. Even at a higher current density of 1000 mA g^-1, there is a capacity decay as low as 0.036% per cycle during 700 cycles. Meanwhile, this work provides a new way of utilizing the metal-organic framework structure and reveals a highly promising PIB anode.

Galvanic Replacement Synthesis of Highly Uniform Sb Nanotubes: Reaction Mechanism and Enhanced Sodium Storage Performance

One-dimensional nanotubes are very useful for achieving excellent performance in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) due to the fact that tubular structures can effectively alleviate the structural strain and shorten the ion diffusion length during repeated cycling. In this work, we report a Cu₂Sb-mediated growth strategy to controllably fabricate highly uniform Sb nanotubes (NTs), as well as Cu@Cu₂Sb and Cu₂Sb@Sb composite NTs, via a facile galvanic replacement reaction using Cu nanowires (NWs) as sacrificial templates. Benefiting from their structural merits, the Sb NTs manifest excellent sodium storage performance with superior rate performance (286 mAh g^-1 at 10 A g^-1) and extraordinary cycling stability (342 mAh g^-1 after 6000 cycles at 1 A g^-1). Furthermore, a full cell with Sb NTs as anode and Na₃(VOPO₄)₂F as cathode exhibits a high energy density (252 Wh kg^-1) and high output voltage (2.7 V), revealing their significant application promise in the next-generation SIBs.

Ultrathin Bismuth Nanosheets for Stable Na-Ion Batteries: Clarification of Structure and Phase Transition by in Situ Observation

Bismuth has garnered tremendous interest for Na-ion batteries (NIBs) due to potentially high volumetric capacity. Yet, the bismuth upon sodiation/desodiation experiencing structure and phase transitions remains unclear, which sets a challenge for accessing nanotechnology and nanofabrication to achieve its applicability. Here, we use in situ transmission electron microscopy to disclose the structure and phase transitions of layered bismuth (few-layer bismuth nanosheets) during Na⁺ intercalation and alloying processes. Multistep phase transitions from Bi → NaBi → c-Na₃Bi (cubic) → h-Na₃Bi (hexagonal) are clearly identified, during which the Na⁺ migration from interlayer to in-plane evokes the structure transition from ABCABC stacking type of c-Na₃Bi to ABABAB stacking type of h-Na₃Bi. It is found that the metastable c-Na₃Bi devotes to buffer the dramatic structure changes from thermodynamic stable h-Na₃Bi, which unveils the origin of volume expansion for bismuth and has important consequences for 2D in-plane structure. As the lateral ductility can efficiently alleviate the in-plane mechanical strain caused by the Na⁺ migration, the few-layer bismuth nanosheet exhibits a potential cyclability for NIBs. Our findings will encourage more attention to bismuthene as a novel anode material for secondary batteries.

Establishing the correlation between catalytic performance and N→Sb donor–acceptor interaction: systematic assessment of azastibocine halide derivatives as water tolerant Lewis acids

A series of organoantimony(iii) halide complexes with a tetrahydrodibenzo[c,f][1,5]azastibocine framework were synthesized and employed as water tolerant Lewis acid catalysts.

Hierarchical nanostructures derived from cellulose for lithium-ion batteries

Recent advances in natural cellulose substance derived hierarchical nanomaterials applied as anodic materials for lithium-ion batteries are summarized.