Sn-based Anode Materials Research Articles

Constructing heterojunction-induced oxygen vacancies of N-doped carbon-encapsulated Sn/SnOx microplates for boosting lithium storage capability

Heterogeneous Sn/SnOx@N-doped carbon (Sn/SnOx@NC) microplates with oxygen vacancies evolved from plate-like SnO powders are successfully fabricated, in which SnO powders are converted into Sn, SnO2, and Sn2O3 phases by rationally sintering and are perfectly in situ encapsulated by polyaniline-derived NC layer. By elaborately constructing the particular structure, high discharge specific capacity of 730.4 mAh/g and capacity retention ratio of 98.3 % after 110 cycles at 0.1 A/g are realized for optimal Sn/SnOx@NC composite electrode. Benefiting from enhanced electronic conductivity and Li+ ions diffusion kinetics, the assembled cell delivers reversible discharge specific capacity of 487.3 mAh/g at 1.0 A/g after 500 cycles. First principles calculation and in/ex situ characterization reveal that in situ formed heterostructure with oxygen vacancies and NC layer synergistically improve interfacial charge transfer and reaction reversibility to promote lithium storage capability. Therefore, fabricating Sn/SnOx@NC microplates may provide a practical strategy to design heterogeneous and oxygen-deficient Sn-based anode materials for high-performance lithium-ion batteries.

C@CoSn2 composite prepared through one-step electro-deoxidation method as anode material of lithium-ion batteries with long-cycle-life and high capacity

Tin is widely studied as an alternative anode material of high-energy-density Li-ion batteries owing to its high theoretical capacity of 993 mAh g–1, low discharge potential, large electrical conductivity, and natural abundance. However, Sn-based anode materials still suffer from large changes in volume during lithium intercalation/de-intercalation processes, leading to cracking and pulverization of electrodes. Herein, carbon is in-situ coated on CoSn2 alloys (C@CoSn2) during the electro-deoxidation process of Co3O4 and SnO2 through the reduction of CO32− in the molten salt of LiCl–KCl–K2CO3. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectrometry all confirm CoSn2 alloys coated with a uniform carbon layer. The sizes of CoSn2 particles decrease to 0.2–1.0 µm due to the surface coating of carbon. The galvanostatic charge/discharge tests suggest discharge capacity and Coulombic efficiency of the optimized C@CoSn2 alloy film electrode reaching 991.5 mAh g–1 and 97.6 % after the 5th cycle, respectively. C@CoSn2 alloy also shows a good rate performance at 2 A g–1 along with a superior retained high capacity of 969.6 mAh g–1 after 300th cycles. Meanwhile, this proposed method looks efficient for the electrochemical fixation of CO2 in molten salts.

(Invited) Conducting Polymers As Dual Charge Conductors for Electrochemical Systems

Electrically conductive polymers are a class of polymers, which can conduct electricity. Conductive polymers have found niche applications such as anti-statics. The electrochemical energy storage devices, especially lithium-ion rechargeable batteries, has grown significantly in the past two decades. Recently multifunctional conductive polymers have been designed as dual ion and electron transport materials, and synthesized through a thermal process. These class of dual charge conducting polymers play a significant role as electrode binders for Silicon (Si) and Tin (Sn) alloy based anode electrode. Si is an attractive candidate for lithium-ion batteries because it delivers 10 times greater theoretical (∼4200 mAh/g) specific capacity than that of a traditional graphite anode (∼370 mAh/g). However, the widespread application of silicon materials has remained a significant challenge because of the large volume change during lithium insertion and extraction processes, disrupting both the Si electrode surface and electrode mechanical integrity. This large volume change causes electrode failure, leading to loss of the electrical contact and drastic capacity fading. Nanosizing the Si and Sn based anode materials provides better performance, but poses significant challenges to manufacturing of the electrode, including particle aggregation, and difficulties in maintaining constant electrical contacts to the nanoparticles, and excessive surface area. Conductive polymer binders can play multiple functions for Si electrode, including improved adhesion and connectivity, lithium ion compensation, better ion and electric conductivity as well as surface and interface modification. Organic and polymer chemistry has provided almost infinity possibilities to modify the polymeric binders to include the desired functionalities. This presentation will discuss the specific molecular design principles and synthetic steps to realize the structures and functionalities of the binders, how these binders interact with different alloy materials, and the electrochemical performances of the electrodes based on these binders.

(Invited) The Application of Conducting Polymers for Nanomaterials Based Alloy Anodes in Battery Manufacturing

Electrically conductive polymers are a class of polymers, which can conduct electricity. Conductive polymers have found niche applications such as anti-statics. The electrochemical energy storage devices, especially lithium-ion rechargeable batteries, has grown significantly in the past two decades. Multifunctional conductive polymers may play a significant role as electrode binders for Silicon (Si) and Tin (Sn) alloy based anode electrode. Si is an attractive candidate for lithium-ion batteries because it delivers 10 times greater theoretical (∼4200 mAh/g) specific capacity than that of a traditional graphite anode (∼370 mAh/g). However, the widespread application of silicon materials has remained a significant challenge because of the large volume change during lithium insertion and extraction processes, disrupting both the Si electrode surface and electrode mechanical integrity. This large volume change causes electrode failure, leading to loss of the electrical contact and drastic capacity fading. Nanosizing the Si and Sn based anode materials provides better performance, but poses significant challenges to manufacturing of the electrode, including particle aggregation, and difficulties in maintaining constant electrical contacts to the nanoparticles, and excessive surface area. Conductive polymer binders can play multiple functions for Si electrode, including improved adhesion and connectivity, lithium ion compensation, better ion and electric conductivity as well as surface and interface modification. Organic and polymer chemistry has provided almost infinity possibilities to modify the polymeric binders to include the desired functionalities. This presentation will discuss the specific molecular design principles and synthetic steps to realize the structures and functionalities of the binders, how these binders interact with different nano Si materials, and the electrochemical performances of the electrodes based on these binders.

Achieving long cycle sodium-ion storage by an “top-down” size control strategy on Sn-based anode

Size control is one of the important strategies to improve the sodium-ion storage performance of Sn-based anode materials. However, the traditional control strategy of “bottom-up” methods still needs to be improved because of their complex processes to obtain nanostructures in Sn anodes. Herein, a simple “top-down” strategy is adopted to realize ultra-small Sn nanoparticles (∼25 nm). This strategy employs in-situ phase transformation technology of Sn nanoparticles, decreasing the size of Sn nanoparticles from 125 to 25 nm successfully. Benefiting from this nanostructure, these ultra-small Sn nanoparticles achieve long cycle sodium-ion storage performance during cycling. As an anode material for sodium-ion batteries, the electrode exhibits a reversible capacity of 387.2 mAh•g−1 after 500 cycles at a current density of 1 A•g−1. Further characterization shows that it has good kinetics performance and structural stability. This work can provide ideas toward the structural design of Sn-based anode to obtain high electrochemical performance in future.

Atomically dispersed Sn incorporated into carbon matrix for stable electrochemical lithium storage

Although possessing a high specific capacity, the practical implementation of SnO2 nanoparticles as a promising anode for lithium-ion batteries (LIBs) is hampered by their poor cyclability. This work demonstrates that incorporating single atomic Sn (SASn) species into a carbon matrix can address this issue effectively. The SASn/C composite was synthesized via polymerization of formaldehyde and 3-aminophenol in the presence of Tin(II) chloride, followed by pyrolysis. The SASn atoms were homogeneously dispersed in the carbon matrix. Each Sn atom coordinated with two O and two C atoms, forming the Sn-O-C and Sn-C bonds, providing channels for fast electron/ion transfer and boosting electrochemical kinetics. The SASn/C anode exhibited unique lithium storage behaviors, enhanced lithium storage capability, and excellent cyclic stability with a capacity fading rate of 0.0031% per cycle at 1000 mA g−1 after 7000 cycles. Density functional theory calculations reveal that one SASn atom can adsorb three Li+ ions at the fully discharged state during the discharging process. Subsequently, the Li+ ions are directly desorbed from the SASn atom, which is different from the traditional multi-step de-alloying process. This facile strategy represents a significant advancement in developing high-performance Sn-based anode materials for LIBs.

Realizing remarkable sodium storage performance of a Sn-based anode material with an oxide-alloy intergrowth structure

Realizing remarkable sodium storage performance of a Sn-based anode material with an oxide-alloy intergrowth structure

Tin-Based Anode Materials for Stable Sodium Storage: Progress and Perspective.

Because of concerns regarding shortages of lithium resources and the urgent need to develop low-cost and high-efficiency energy-storage systems, research and applications of sodium-ion batteries (SIBs) have re-emerged in recent years. Herein, recent advances in high-capacity Sn-based anode materials for stable SIBs are highlighted, including tin (Sn) alloys, Sn oxides, Sn sulfides, Sn selenides, Sn phosphides, and their composites. The reaction mechanisms between Sn-based materials and sodium are clarified. Multiphase and multiscale structural optimizations of Sn-based materials to achieve good sodium-storage performance are emphasized. Full-cell designs using Sn-based materials as anodes and further development of Sn-based materials are discussed from a commercialization perspective. Insights into the preparation of future high-performance Sn-based anode materials and the construction of sodium-ion full batteries with a high energy density and long service life are provided.

Elaborate interface design of SnS2/SnO2@C/rGO nanocomposite as a high-performance anode for lithium-ion batteries

The practical application of Sn-based anode materials is limited by their low electrical conductivity and large volume expansion during cycling. To overcome these challenges, a novel SnS2/SnO2@C/rGO nanocomposite is synthesized by in-situ H2O2 oxidation of SnS2@C/rGO that is prepared via a hydrothermal reaction using SnCl2, thiourea, L-ascorbic acid and GO as the reactants. Tightly contacted SnS2/SnO2 heterostructured nanoparticles are encapsulated by the amorphous carbon derived from L-ascorbic acid, which are further firmly anchored on the rGO sheets through the chemical interactions between the hydroxyl groups of L-ascorbic acid and hydroxyl/carbonyl groups of rGO. The amorphous carbon layer can act as a spacer to prevent the stacking of rGO sheets to retain the ion transport pathway. Meanwhile, the N and S heteroatoms are co-doped into the rGO sheets by using thiourea as N and S sources, which can enhance the electrical conductivity and provide more active sites for Li+ insertion/extraction. The obtained nanocomposite exhibits a specific capacity of 689 mA h g−1 after 300 cycles at a current density of 0.1 C (1 C = 783 mA g−1) and a moderate capacity of 619 mA h g−1 up to 500 cycles at a large current rate of 0.5 C.

Metal–organic framework-derived carbon decorated Ni–Sn nanostructures for ultrastable metal-ion batteries

Sn-based anode materials have been considered with great potential for advanced metal-ion batteries contributed to their fascinating cost efficiency and relatively high theoretical capacity. Nevertheless, their severe volume expansion hinders the commercial applications. Herein, a facile strategy has been proposed to design carbon nanotube-decorated Ni–Sn nanostructures (Ni–Sn@CNT) via catalytic conversion from the Ni-MOF@SnO2 precursor. In such unique architecture, the metallic Ni acts as a buffer matrix (electrochemically inactive phase) to effectively suppress the unfavorable volume variation of Sn during the long-term battery operation and the conductive CNT network offers sufficient electron and ion transport pathway. Benefitting from these features, the as-prepared Ni–Sn@CNT nanostructures harvest a decent capacity of 408.7 mAh g−1 and 91 mAh g−1 for storing Li+ and Na+ after 500 cycles, respectively.

The study on nanostructural evolution of SnO2-carbon aerogel nanocomposite during the first discharge process

SnO2 has attracted great attention at energy storage due to the high capacity. The electrochemical conversion behavior of SnO2 as well as its influence on the lithium-storage performance remains unclear because of its pulverization and aggregation. In this paper, SnO2-carbon aerogel (CA) composites were characterized by TEM, SEM, XRD, XPS, FTIR, TG/DTG and BET. SnO2-CA anode materials exhibit excellent cycling stability and a strong rate capacity. The nanostructural evolution of SnO2-CA as anode material were studied by in situ electrochemical-grazing incidence small angle X-ray scattering (GISAXS) technique. The GISAXS results demonstrate that the multihierarchical scatterers in the SnO2-CA as anode material can be roughly divided into interspace, SnO2 nanoparticles, nanopores and so on during the first lithiation. The nanostructural evolution of SnO2 nanoparticles are observed and subsequently some cracks occur that result from the existence of tension stress during the first discharge process. At the same time, the volumes of interspaces and nanopores also expand slightly during Li-ion intercalation process. A schematic model has been tentatively proposed to describe the first lithiation of SnO2-CA anode. It is firmly believed that these results will help further understanding of the complicated reaction mechanism of nanostructured Sn-based anode materials and provide a valuable insight into designing new electrode materials.

Tin nanoparticle/3D framework carbon composite derived from sodium citrate as the stable anode of lithium-ion batteries

Sn-based anode materials have gained more attention for application in lithium-ion batteries (LIBs), due to tin having the characteristics of high specific capacity, low cost, and environmentally friendly. However, low capacity retention due to the large volume changes upon lithiation/delithiation limits their further development. In this paper, tin nanoparticle/3D framework carbon composite (denoted as Sn@SC) is obtained by calcining the composite of trisodium citrate and stannous sulfide. The Sn@SC composite delivers a stable cycling capacity of 410.9 mAh/g after 150 cycles and 300.1 mAh/g after 950 cycles at 1 A/g. The excellent electrochemical performance can be assigned to the fact that the hollow porous carbon can provide enough space for the volume change of tin nanoparticles in the step-by-step alloying process and shorten the electron transport path, thus increasing the structural stability and rate capability.

Design of double-shell TiO2@SnO2 nanotubes via atomic layer deposition for improved lithium storage

TiO2@Void@SnO2 nanotubes synthesized by atomic layer deposition (ALD) display high capacity for lithium storage.

MOFs and their derivatives as Sn-based anode materials for lithium/sodium ion batteries

The increasing research of Sn-MOFs and Sn-based MOF-derivatives opens new avenues in promising anode materials for lithium/sodium ion batteries.

Hierarchical SnS2/carbon nanotube@reduced graphene oxide composite as an anode for ultra-stable sodium-ion batteries

Ultrathin SnS2 layers with high theoretical specific capacity displays promising advantages as an anode in sodium storage systems. However, their poor conductivity and large capacity loss during charging/discharging process are urgently needed to be addressed. Herein, an exotic hierarchical SnS2/carbon nanotube@reduced graphene oxide (SnS2/CNT@rGO) composite has been designed and developed to be an anode for sodium-ion batteries. Functionally, the CNT penetrates into the petals of SnS2 micro-flowers to increase the conductivity of SnS2, while the three-dimensional rGO wraps around the SnS2/CNT composite to relieve the volume expansion of SnS2 during the charging/discharging process and construct “rGO conductive bridge” to accelerate electrode reaction kinetics. Benefiting from these exotic functionalization, the SnS2/CNT@rGO anode possesses excellent reversible capacity and superior cycling stability with a high reversible capacity of 528 mA h g−1 at 50 mA g−1 and a retained capacity of 301 mA h g−1 after 1000 cycles at 1 A g−1, which are better than most of the previously reported Sn-based and carbon-based anode materials. This study offers a promising strategy for significantly improving the cycling stability in the ultra-stable electrode materials in sodium-ion batteries.

Uniformly depositing Sn onto MXene nanosheets for superior lithium-ion storage

Sn is promising anode material with high specific capacity for next-generation lithium-ion batteries (LIBs), while the severe volume expansion and poor conductivity of Sn during lithiation/de-lithiation process result in dramatic capacity fading with poor cycle life. Therefore, exploring Sn-based anode materials with excellent structural stability and electrical conductivity is essential for high-performance LIBs. Herein, we propose the fabrication of a nanostructured Sn@Ti3C2Tx composites where Sn species are tightly attached onto the Ti3C2Tx nanosheets uniformly via electrostatic attraction followed by reduction. The Ti3C2Tx nanosheets, acting as a support and electron conductor of Sn, can effectively improve electron transport and electrode stability. Moreover, the Ti3C2Tx nanosheets with rich functional surface groups tend to form strong interfacial interactions with Sn, beneficial for the uniform distribution of Sn and stable lithium storage. As a result, the Sn@Ti3C2Tx electrode exhibits significantly improved battery performance compared with the Micro-Sn@Ti3C2Tx electrode. This work may shed lights on the development of advanced Sn-based anode materials for high-performance LIBs.

A Nano-Rattle SnO2@carbon Composite Anode Material for High-Energy Li-ion Batteries by Melt Diffusion Impregnation.

The huge volume expansion in Sn-based alloy anode materials (up to 360%) leads to a dramatic mechanical stress and breaking of particles, resulting in the loss of conductivity and thereby capacity fading. To overcome this issue, SnO2@C nano-rattle composites based on <10 nm SnO2 nanoparticles in and on porous amorphous carbon spheres were synthesized using a silica template and tin melting diffusion method. Such SnO2@C nano-rattle composite electrodes provided two electrochemical processes: a partially reversible process of the SnO2 reduction to metallic Sn at 0.8 V vs. Li+/Li and a reversible process of alloying/dealloying of LixSny at 0.5 V vs. Li+/Li. Good performance could be achieved by controlling the particle sizes of SnO2 and carbon, the pore size of carbon, and the distribution of SnO2 nanoparticles on the carbon shells. Finally, the areal capacity of SnO2@C prepared by the melt diffusion process was increased due to the higher loading of SnO2 nanoparticles into the hollow carbon spheres, as compared with Sn impregnation by a reducing agent.

Yolk-shelled Sn@C@MnO hierarchical hybrid nanospheres for high performance lithium-ion batteries

Metallic tin exhibits great potential as an alternative to commercial graphite anode materials. However, its tremendous volume change during cycles leads to significant capacity fading, which hampers its practical application. In this work, Sn nanoparticles are confined to a carbon nanocage to form Sn@C@MnO yolk-shell hierarchical hybrid nanospheres as anode nanomaterials for Li-ion battery. In the novel nanostructures, the yolk-shell nanostructures can well buffer the volume contraction/expansion of Sn nanocores during cycles; the carbon shell can provide high conductivity and inhibit Sn and MnO nanocrystals from stacking; MnO nanocrystals on the C shell can not only offer sufficient active sites for Li-ion adsorption, but also validly consolidate the structural stability of the shell in the yolk-shell nanostructure. Benefiting from the unique nanostructures, Sn@C@MnO yolk-shell hierarchical hybrid nanospheres exhibit superior electrochemical lithium storage performances (822mAhg−1 after 250 cycles at 0.1Ag-1) and long-term cyclic stability (603mAhg−1 after 500 cycles at 0.5Ag-1). This work offers valuable insight into the synthetic strategy of Sn-based anode materials with novel hierarchical hybrid nanostructures.

SnS2 nanoparticle-integrated graphene nanosheets as high-performance and cycle-stable anodes for lithium and sodium storage

With the intensification of environmental pollution problems, the requirement for clean energy is increasing as time goes by. Currently, lithium-ion batteries (LIBs) composed of graphite anode cannot meet the commercial demand of human beings. Furthermore, considering the viewpoint that sodium-ion batteries (SIBs) were promising in large-scale energy storage, we synthesize a hybrid of SnS2 nanoparticle-integrated graphene nanosheets (SnS2@GNS) by a facile and simple method. The unique structure that SnS2 and GNS bonded by covalent bonds makes it displays excellent performance for lithium/sodium storage. Especially in LIBs, when tested at 0.1 A g−1, it delivers 1250.8 mA h g−1 after cycling 150 times which is much higher than previously reported Sn-based anode materials. In addition, it sustains 798.6 mA h g−1 without obvious capacity decay when the rate changed to 0.5 A g−1. Moreover, when employed in SIBs, it also delivers superior cycle performance (510.2 mA h g−1 after 100 cycles), which makes it possible to apply in LIBs and SIBs at the same time.

Solubility-dependent gelatination toward N-doped SnOx/C deriving from commercial SnO2 for the ultrastable lithium storage

More than 200% volume change is the major restriction for the practical application of Sn-based anode materials in lithium-ion batteries. In order to prepare carbon-coated structure by a facile, low-cost, facile and common method, the solubility-dependent gelatination of carboxylated chitosan is developed for the precursors of N-doped SnOx/C composites with commercial SnO2 nanoparticles as Sn source. The phase, porosity and ratio of Sn/C of the composites can be easily controlled by changing the raw materials ratio and calcination temperature. According to the results, N-doped SnOx/C anode material shows excellent stability (93.9% retention of the second cycle) and superior specific capacity (679.8 and 542.3 mAh g−1 after 300 cycles at 200 mA g−1 and 1000 mA g−1, respectively). This strategy lights on the illuminating design of 3D carbon-coated Sn-based anode by liquid carbon source and commercial solid tin source, which can improve electrochemical performance for next-generation lithium-ion batteries.