High-performance Lithium-ion Battery Anodes Research Articles

Facile Synthesis Sandwich-Structured Ge/NrGO Nanocomposite as Anodes for High-Performance Lithium-Ion Batteries

This work aimed to design a facile preparation of sandwich-liked Ge nanoparticles/nitrogen-doped reduced graphene oxide (Ge/NrGO) nanocomposites used as anode in lithium-ion batteries through the chemical solution route. The advanced electron microscopy, STEM-HAADF and STEM-EDS mapping, evidenced that the individual Ge particles with sizes ranging from 5 to 20 nm were distributed and wrapped as sandwiches within the multi-layered NrGO sheets, which were mainly composed of the pyridinic-N form (4.8%wt.). The battery performances of the 20Ge/NrGO nanocomposite anode exhibit a high reversible capacity (700 mAh g−1) and retained its outstanding stability during long-term cycling. The internal resistance (28.0 Ω) was also decreased after cycling, according to EIS measurement. The sandwiched structure of Ge-based nanocomposite with the interconnected NrGO layers discussed in this article possessed the high-performance LIBs with great potential application in energy storage technologies.

Porous engineering enables one-dimensional CoxOy/C composite to enhance lithium storage

Herein, in order to improve performance of cobalt oxides for lithium-ion battery anodes, a one-dimensional porous CoxOy composed of CoO and Co3O4 has been fabricated and further coated by a characteristically porous layer of carbon through a facile integrated porous engineering. The as-prepared CoxOy@porous carbon (CoxOy@PC) composite therefore integrates the advantages of the one-dimensional and porous structures. Thus architecture successfully boosts the structural stability and efficiently enhances the electrochemical kinetics of the CoxOy@PC anode. The results reveal that the CoxOy@PC anode shows significantly improved performance with 964.7 and 908.6 mA h g−1 at 200 and 1000 mA g−1 after 200 and 100 cycles, respectively. It demonstrates that the porous engineering plays an important role in improving performance of CoxOy@PC anode, which is conducive to mitigation of volume change, permeation of electrolyte, and ion diffusion and mass transport. This CoxOy@PC therefore shows great promise in application of high-performance anode for lithium-ion batteries. Moreover, this study gives an efficient strategy to concern the intrinsic drawbacks of the cobalt oxide anodes, which could be extended to other high capacity of metallic oxide-based anodes toward high energy-density batteries.

Fullerene-like elastic carbon coatings on silicon nanoparticles by solvent controlled association of natural polyaromatic molecules as high-performance lithium-ion battery anodes

Carbon coating is one of the most common methods to improve the performance of Li-ion batteries, especially for materials such as silicon and silicon oxides (SiOx) of poor electronic conductivity and large volume changes during cycling. However, its brittle nature and low elasticity make the conventional carbon coatings crack easily and hence lose the conductive connection with active materials after a few cycles. In this work, we propose a scalable and low-cost synthesis method to deposit a highly-elastic fullerene-like protective carbon layer on silicon nanoparticles by molecular-level controlled association of natural polyaromatic molecules in heavy oil. The fullerene-like carbon layer is shown to recover by > 90% after deformation, which ensures the structural stability of the carbon coatings during cycling. Fullerene-like carbon coated silicon nanoparticles exhibit a high cycle stability with a reversible capacity of 1230 mAh g-1 and capacity retention of 94.6% after 600 cycles at 1 C. These results demonstrate the great commercial potential of this synthesis method in producing anode materials of high-performance lithium-ion batteries.

One-pot synthesis of MnO-loaded mildly expanded graphite composites as high-performance lithium-ion battery anode materials

Improving the properties of conventional graphite anode materials has been an important research topic for enhancing the performances of lithium-ion batteries (LIBs). Herein, we develop a facile one-pot approach to mildly expand graphite (MEG) and simultaneously load MnO onto the as-prepared MEG to synthesize MnO@MEG composites as high-performance anode materials for LIBs. With the improved porous structure and electrical conduction network, both the MEG and MnO components of the composite exhibit well-defined electrochemical properties and alleviated volume changes upon charge/discharge, synergistically enhancing the electrochemical performances for our composites. With a high active material content and high mass loading for the testing electrode, the optimized MnO@MEG composite shows a high capacity (437.77 mAh g−1 at 0.1 C), a high rate capability (capacity retains 71.93% at 1 C vs. 0.1 C), and a high cycling stability (capacity retains 73.17% and 68.13% after charge/discharge at 0.5 C and 1 C, respectively, for 50 cycles), significantly outperforming its pristine graphite counterpart and previously reported similar MnO composites with other carbon materials, thereby standing for a practically promising anode material for LIBs. Broadly, the one-pot approach developed in the present work can be extended for producing other graphite-based composites for other energy-related technologies.

Dual-layer carbon protected coaxial cable-like Si-based composites as high-performance anodes for lithium-ion batteries

The Si-based composites (NC@Si@CNTs) are synthesized successfully by a facile route. Using tetraethylorthosilicate as Si-source, carbon nanotubes (CNTs) and polydopamine as C-source, a dual-layer carbon protected coaxial cable-like structure is achieved. As an anode for Li-ion battery, the dual-layer carbon protection to Si layer gives a initial specific discharge and reversible specific discharge capacity of 2804 and 1752 mAh g−1 at 200 mA g−1 after 150 cycles. Even at 2 A g−1, the NC@Si@CNTs electrode can still display an initial and reversible specific capacities of 2297 mAh g−1 and 910 mAh g−1. The dual-layer carbon protected coaxial cable-like structure also improves the rate performance and cycling stability greatly compared to Si. This might be ascribed mainly to high conductivity and buffer effect of two carbon layers during cycling, which provide more effective transmission paths for electrons and promote fast diffusion for Li ions. In addition, the N-doping of carbon layer for extra Li ions and more stable structure of the as-prepared coaxial cable also contribute to the enhanced specific capacity and cycle stability during the charging/discharging process.

In situ measurement and mechanism analysis of the lithium storage behavior of graphene electrodes

Graphene has attracted widespread attention for development of high-performance lithium-ion battery anode materials. In this paper, the lithium storage mechanisms of multilayer graphene, few-layer graphene, and reduced graphene oxide electrodes are investigated, and the influences of layers and defects in the microstructure are analyzed. The evolution of microstructure deformation of different graphene electrodes, combined with the diffusivity and distribution of lithium, is systemically investigated by in-situ Raman spectroscopy during lithiation and delithiation. The results show that graphene electrodes with different structures exhibit different mechanical behaviors and thus different lithium storage capacities. Mechanical analysis indicates that although the surfaces and defects are active, interlayer lithium insertion contributes the most lithium storage capacity. As the number of graphene layers increases and/or defects decrease, more interlayer spaces would be provided. Thus, the lithium storage capacity of multilayer graphene is significantly higher than those of few-layer graphene and reduced graphene oxide. An in-depth understanding of the effect of the microstructure on the lithium storage behavior of graphene electrodes will provide an experimental basis for development of high-performance graphene electrodes.

Scalable synthesis of Li2GeO3/expanded graphite as a high-performance anode for Li-ion batteries

A simple, economical, and easily scalable high-energy ball-milling method for the synthesis of Li2GeO3/expanded graphite (LGO/EG) as a high-performance anode for lithium-ion batteries is reported. The LGO/EG exhibits a unique architecture with expanded graphite (EG) uniformly coating Li2GeO3 (LGO) particles, which effectively inhibited the agglomeration of LGO particles. The LGO/7 wt%EG anode delivers a discharge capacity of 800.6 mA h g−1 at 5.0 A g−1, with an outstanding capacity retention of 75.9% after 300 cycles at 1.0 A g−1, which is 8.3% higher than that of the uncoated LGO anode. This is attributed to the introduction of EG which improves the electronic conductivity of LGO, and the uniformly coated EG can effectively inhibit the volume change of LGO particles during the charging-discharging process. As a result, LGO/EG has outstanding high-rate performance and long-term cycle stability.

Controlling precise voids in the ion-selective carbon shell for zero-strain electrode

Low-strain nanoarchitectures are the precondition for offering a stable electrochemical environment towards high-performance lithium-ion battery anode in the compaction system. Realizing the zero-strain for each particle of high-capacity anode is a scientific challenge, because of huge volume changes arising during the insertion/extraction process of Li+. Herein, we develop a facile and general strategy to construct a freestanding transition metal oxides (TMOs) anode with consecutive nanoarrays of yolk-shell nanorods. By confining the dehydration process in the ion-selective carbon-ene‑yne (CEY) nanotubes, free space can be precisely created for alleviating the excessive volume expansion of internal particles. The all-carbon CEY not only conducts the electrons and supports the nanoarchitecture of the anode, but also provides the high-areal-density atomic-level selective channels for Li+ diffusion and prevents the electrolyte from decomposition. The as-obtained strainless anode demonstrates an ultra-stable architecture and interface during cycling, leading to a high specific capacity and enhanced cycling ability. Our result demonstrates the significant advantages to largely produce zero-strain architecture, towards ideally solving the crucial issues confronted in the high-volume-change electrode.

Facile fabrication of hierarchical porous silicon/N-doped carbon composites via biomass fermentation treatment for high-performance lithium-ion batteries

Despite the ultrahigh theoretical capacity of Si anodes, their commercial application is severely restricted due to the lack of scalable and low-cost methods to overcome their considerable volume deformation and poor electrical connectivity. Herein, a novel hierarchical porous silicon/N-doped carbon composite (Si/N-PC) is successfully fabricated via simple biomass fermentation with inexpensive wheat flour, and this composite is then used as a high-performance lithium-ion battery (LIB) anode. Wheat flour blended with silicon nanoparticles can be fermented under the action of yeast while releasing carbon dioxide to construct a unique hierarchical porous structure. The added cationic surfactant hexadecyltrimethylammonium bromide not only helps uniformly deposit the Si particles in the wheat flour under the action of electrostatic forces but also forms an N-doped carbon layer in combination with the protein in the wheat flour, realizing full utilization of the raw materials. Systematic tests verify that the N-doped hierarchical porous structure contributes to mitigating the volume change, ensuring electrode stability and enhancing the electrical conductivity of the Si/N-PC composite during the charge-discharge process. As anticipated, the obtained Si/N-PC composite electrode can maintain a reversible discharge capacity of 696.1 mAh g−1 for over 300 cycles at a current density of 1 A g−1, exhibiting a 0.17% capacity loss per cycle from the 3rd to 300th cycle. Additionally, this composite electrode delivers a superior rate capability of 946.1 mAh g−1 at a high current density of 2 A g−1, showing the synergistic benefit of the hierarchical porous structure and N doping. This is the first time that a hierarchical porous silicon/N-doped carbon composite has been prepared via biomass fermentation treatment for use in high-performance LIBs. The overall fabrication process of the Si/N-PC composites is low cost and scalable, providing a sustainable strategy for the production of high-performance Si/C anode materials.

Electrochemical and transport properties of Te-doped Li4Ti5O12 as anode material for lithium-ion half/full batteries

Te-doped Li4Ti5O12 (LTO) was prepared by a ball milling-assisted solid-state method in air. The as-prepared powders were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and electrochemical impedance spectroscopy. Li4Ti4.95Te0.05O12 powder sintered at 850 °C presented improved ionic and electronic conductivities of 2.20 × 10-7 S·cm-1 and 2.40 × 10-9 S·cm-1 at room temperature, respectively, an order of magnitude higher than those of intrinsic LTO. Electrochemical analysis showed that the discharge specific capacities of Li4Ti4.95Te0.05O12 in Li half cells at 1 C and 5 C were 162.49 mAh·g-1 and 143.5 mAh·g-1, respectively, with capacity retention rates of 98.8% and 98.2% after 100 cycles. The Li4Ti4.95Te0.05O12/LiNi0.5Mn0.3Co0.2O2 full cells also showed a good specific capacity of 101.8 mAh·g-1 at 1 C and delivered good temperature adaptability. This study provides an effective strategy for the preparation of high-performance LTO anodes for lithium-ion batteries.

Atomic layer deposited aluminum oxynitride coating for high-performance Si anode in lithium-ion batteries

Silicon (Si) has received great attention as a promising anode material for lithium-ion batteries (LIBs) due to its high gravimetric capacity and large abundance. However, the use of Si anodes in LIBs has been hindered by their inferior electrochemical performance, resulting from its vast volume expansion and unstable solid electrolyte interphase (SEI). To address these problems, a novel surface coating material, aluminum oxynitride (AlOxNy), was developed using a plasma-enhanced atomic layer deposition technique with trimethylaluminum and plasma N2/H2 as the precursors. The effects of AlOxNy surface coatings on the electrochemical properties of Si electrodes were investigated. With the optimal AlOxNy coating (∼2 nm), the reversible capacity after 140 cycles was improved from 331 mAh g−1 for bare Si electrode to 1297 mAh g−1 for AlOxNy-coated one, and the capacity retention was elevated from 13% to 72%. Post-cycling analysis revealed that the AlOxNy coating significantly suppressed the charge transfer and SEI resistances and maintained the structural integration of Si electrodes by suppressing continuous electrolyte decomposition and electrode delamination from the current collector. This study provides a new perspective on designing advanced functional coating materials for atomic layer deposition for lithium-ion batteries.

Carbon-coated BiVO4 prepared by molten salt method combined with ball milling for high-performance lithium-ion battery anode

Carbon-coated BiVO4 prepared by molten salt method combined with ball milling for high-performance lithium-ion battery anode

A novel hollow Co3O4@N-doped carbon nanobubble film composite for high-performance anode of lithium-ion batteries

Co 3 O 4 nanomaterials and their composites are replacing carbon as anode materials of lithium-ion batteries (LIBs) because of their large theoretical capacity, low cost and high abundance. However, the volume expansion in the process of charging/discharging leads to the destruction of Co 3 O 4 nanomaterials and thus results in poor cyclic stability, which limits their practical application seriously. Herein, a novel N-doped carbon nanobubble film (CNBF) with hollow Co 3 O 4 nanomaterials (H–Co 3 O 4 ) composites (H–Co 3 O 4 @CNBF) was prepared by proposing covalent-organic framework (COF) as template and carrier of Co 2+ . Using in-situ anchoring H–Co 3 O 4 strategy, a two-step calcination method was employed to prepare H–Co 3 O 4 @CNBF. The obtained H–Co 3 O 4 @CNBF exhibited a good lithium storage ability originated from anchored H–Co 3 O 4 nanomaterials and high cycle performance as the anode of LIBs came from the buffering of CNBF. The as-prepared H–Co 3 O 4 @CNBF showed excellent capacity of 808.0 mA h g −1 after 100 cycles at 0.2 A g −1 and outstanding cycle stability of 540.0 mA h g −1 after 200 cycles at 2 A g −1 . The combination of CNBF derived from COFs with H–Co 3 O 4 is a good strategy, which provides a new guide for the preparation of novel metal oxides and carbon composites. •A novel N-doped carbon nanobubble film with hollow Co 3 O 4 was prepared by using covalent organic framework. • The composites exhibit good Li + storage ability originated from anchored hollow Co 3 O 4 nanoparticles. • The composites exhibit high cycle performance originated from N-doped carbon nanobubble film. • This core-shell structure of composites can avoid the damage caused by volume expansion of Co 3 O 4 effectively.

Recovery of porous silicon from waste crystalline silicon solar panels for high-performance lithium-ion battery anodes.

A low-cost and easy-available silicon (Si) feedstock is of great significance for developing high-performance lithium-ion battery (LIB) anode materials. Herein, we employ waste crystalline Si solar panels as silicon raw materials, and transform micro-sized Si (m-Si) into porous Si (p-Si) by an alloying/dealloying approach in molten salt where Li+ was first reduced and simultaneously alloyed with m-Si to generate Li-Si alloy at the cathode. Subsequently, the as-prepared Li-Si alloy served as the anode in the same molten salt to release Li+ into the molten salt, resulting in the production of p-Si by taking advantage of the volume expansion/contraction effect. In the whole process, Li+ was shuttled between the electrodes in molten LiCl-KCl, without consuming Li salt. The obtained p-Si was applied as an anode in a half-type LIBs that delivered a capacity of 2427.7 mAh g-1 at 1 A g-1 after 200 cycles with a capacity retention rate of 91.5% (1383.3 mAh g-1 after 500 cycles). Overall, this work offers a straightforward way to convent waste Si panels to high-performance Si anodes for LIBs, giving retired Si a second life and alleviating greenhouse gas emissions caused by Si production.

Two-Dimensional Cu2MoS4-Loaded Silicon Nanospheres as an Anode for High-Performance Lithium-Ion Batteries

Silicon-based anode materials have a theoretical capacity 10 times that of commercial graphite and have attracted attention. Herein, a creative and effective strategy is elaborated for the synthesi...

Synthesis of freestanding binder- and additive-free carbon nanofiber with graphene-wrapped Nb2O5 composite anode for lithium-ion batteries

Niobium pentoxide (Nb2O5)-based materials have attracted significant interest for application in diverse fields. Unfortunately, the employment of these materials as electrodes of lithium-ion batteries (LIBs) is limited by several inherent drawbacks. The present study demonstrated the synthesis of composites comprising homogeneous graphene-wrapped niobium pentoxide (GNbO) encapsulated in carbon nanofibers (CNFs) for utilization as binder- and additive-free anodes in LIBs. The composites were synthesized via electrospinning and subsequent carbonization; the presence of graphene (G) ensured the homogenous dispersion of the Nb2O5 particles in the CNF matrix. The CNFs formed a highly conductive network that resulted in high physical flexibility, electrical conductivity, and structural stability during charge–discharge cycles, thereby facilitating rapid ion/electron transmission. Consequently, the CNF/GNbO composite anodes exhibited outstanding electrochemical performances. CNF/GNbO_5 (one of the synthesized composites with an Nb2O5 concentration of 5 wt% relative to GO) delivered a specific capacity of 361 mAh g−1 after 100 cycles, corresponding to a capacity retention of 58.3%. In addition, it exhibited an excellent rate capability with a capacity of 317 mAh g−1 at 10 C. The outcomes of the present study will facilitate the extensive application of the synthesized composites as high-performance anodes in next-generation LIBs.

Polyvinylpyrrolidone regulated synthesis of mesoporous titanium niobium oxide as high-performance anode for lithium-ion batteries

TiNb2O7 (TNO) as a promising candidate anode for lithium-ion batteries (LIBs) shows obvious advantages in terms of specific capacity and safety, but which undergoes the intrinsic poor electrical and ionic conductivity. Herein, we propose a simple synthesis strategy of mesoporous TNO via a polymeric surfactant-mediated evaporation-induced sol-gel method, using polyvinylpyrrolidone (PVP) with different molecular weights (average Mw: 10000/58000/1300000) as the regulating agent, which greatly affects the lithium storage performance of the as-prepared TNO. The optimized TNO (i.e., PVP of 58000) delivers a high reversible capacity of 303.1 mAh/g at 1 C, with a retention rate of 73.4% (222.5 mAh/g) after 300 cycles. Even at 5 C, a high reversible capacity of 185.6 mAh/g can be achieved, with a retention rate of 72.3% after 1000 cycles. The superior lithium storage behavior is attributed to the fine mesoporous framework consisting of interconnected TNO nanocrystallites with high specific surface area and high mesoporosity, which greatly increases the active sites, improves the Li+ diffusion kinetics and alleviates volume fluctuation induced by the repetitive Li+ insertion-extraction processes.

Incorporation of Fe3O4 nanoparticles in three-dimensional carbon nanofiber/carbon nanotube aerogels for high-performance anodes of lithium-ion batteries

Recently, Fe3O4 based materials have been widely investigated to serve as anode materials of lithium-ion batteries (LIBs) because of the high theoretical capacity (924 mA h g−1). Unfortunately, the actual capacity of these materials are low and they suffer from poor cycling stability. Herein, carbon nanotube/carbon nanofiber composite aerogels (CA) were used as scaffold to fabricate Fe3O4-CA composites for anode materials. Fe3O4 nanoparticles were evenly presented on the external surface and internal channel of the 3-dimensional (3D) CA network. The 3D conductive network can buffer the volume expansion of anode materials. Additionally, such structure can prevent the aggregation of Fe3O4. Therefore, the structure of the Fe3O4-CA composite electrode can be maintained during lithiation/delithiation processes. The Fe3O4-CA composites delivered a high reversible capacity of 825.1 mA h g−1 after 100 cycles. Additionally, an ultra-high coulombic efficiency closed to 100% was obtained. The excellent performance of the Fe3O4-CA composites may be due to the synergistic effect of the Fe3O4 nanoparticles and 3D conductive network structure.

2D nanosheets from fool’s gold by LPE: High performance lithium-ion battery anodes made from stone

Recently, it has been shown that it is possible to apply liquid-phase exfoliation to non-layered materials, yielding quasi-2D nanosheets. It has been proposed that even a slight bonding anisotropy in the starting crystal will lead to a platelet-like geometry, albeit with low aspect ratio. While this development opens the way to many previously unexplored 2D materials, a particularly interesting class of crystals for exfoliation are natural-occurring mineral ores due to their diversity and abundance. Here we describe the liquid-phase exfoliation of the natural mineral, pyrite, also known as fool’s gold. The exfoliation process yields highly crystalline, low aspect ratio nanosheets with stoichiometry FeS2, with all impurity and non-platelet material removed during a two-step centrifugation protocol. These 2D pyrite flakes can be fabricated into lithium-ion battery anodes which show remarkable capacities of >1200 mAh g−1.

SnS particles anchored on Ti3C2 nanosheets as high-performance anodes for lithium-ion batteries

Tin sulfide (SnS) has been regarded as one of the most attractive anode materials for lithium-ion batteries (LIBs) because of its high specific capacity. However, its large volume expansion (>300%) and low electronic conductivity restrict its application. In this study, Sn2+ was anchored on Ti3C2 nanosheets through electrostatic attraction, and Ti3C2@SnS@C was synthesized through a hydrothermal method. The obtained Ti3C2@SnS@C exhibits excellent rate performance and cycle performance and effectively serves as an anode material for LIBs. It has a stable capacity of 563.5 mAh/g after 420 cycles at 500 mA/g, and this value is much higher than that of commercially available anode materials. Ti3C2 can also effectively inhibit the volume expansion of SnS particles. The volume expansion of Ti3C2@SnS@C electrode is only 56.8% after 420 cycles at 500 mA/g. This finding is much better than that of pure SnS@C electrode (209.3%).