High-performance Li-ion Battery Anodes Research Articles

Hierarchical conformal coating enables highly stable microparticle Si anodes for advanced Li-ion batteries

Microsized silicon powders have great potential for high capacity anode materials in next-generation lithium ion batteries, because of the high gravimetric and volumetric energy densities, ease of mass production and low costs. However, large volume change and consequently rapid capacity fading upon lithiation and delithiation prevent its practical applications. Herein, we demonstrate an effective hierarchical conformal coating strategy for high-performance microsized Si anodes. The Si-based composites consist of an amorphous Li-Si-O inner coating layer and a graphene outer encapsulation layer, which are prepared by coupling reactive milling with electrostatic self-assembly. This unique hierarchical conformal coating structure not only strengthens the mechanical property (31.8 GPa for the elastic modulus) and promotes the ionic diffusion (2.03 × 10−10 cm2 s−1) of Si anode, but also effectively stabilizes the electrode/electrolyte interfaces and increases the electronic conductivity. As a result, a high reversible capacity (1450 mA⋅h g−1 at 0.1 A g−1), good cycling stability (97.7% of capacity retention from the 2nd to the 310th cycle at 0.5 A g−1), and high rate capability (703 mA⋅h g−1 at 5 A g−1) have been successfully achieved. These findings provide new insights into the improvement of electrochemical properties of microsized Si composite anodes for high-performance Li-ion batteries.

Ultra-small ZnS quantum dots embedded in N-doped carbon matrix for high-performance Li-ion battery anode

We report zinc sulfide (ZnS) quantum dots composed of three different polymorphs (pure zinc blende, pure wurtzite, and poly-type (zinc blende/wurtzite)) uniformly embedded in an N-doped carbon matrix as a potential electrode material for anode applications in lithium-ion batteries (LIBs), for the first time. The ZnS polymorph quantum dots with cubic and hexagonal lattices anchored onto a N-doped carbon matrix ([email protected]) electrode is prepared by a polyol-assisted pyro-synthesis technique. A combined operando XRD and ex-situ XAS analyses revealed that the electrochemical reaction mechanism in [email protected] was reversible and comprised of an insertion reaction followed by a conversion-cum-alloying reaction. Due to the structural property of the composite and its unique electrochemical behavior, the [email protected] electrode registers a reversible specific capacity as high as 800 mAhg−1 with a high initial energy round-trip efficiency of 83%, and better cycling stability and power. The results from this study can help in the production of high-performance electrode materials with unique structural and morphological composition using an efficient pyro-synthetic reaction for rechargeable battery applications.

Rapid Synthesis of High-Entropy Oxide Microparticles.

High-entropy nanoparticles have received notable attention due to their tunable properties and broad material space. However, these nanoparticles are not suitable for certain applications (e.g., battery electrodes), where their microparticle (submicron to micron) counterparts are more preferred. Conventional methods used for synthesizing high-entropy nanoparticles often involve various ultrafast shock processes. To increase the size thereby achieving high-entropy microparticles, longer reaction time (e.g., heating duration) is usually used, which may also lead to undesired particle overgrowth or even densified microstructures. In this work, an approach based on Joule heating for synthesizing high-entropy oxide (HEO) microparticles with uniform elemental distribution is reported. In particular, two key synthesis conditions are identified to achieve high-quality HEO microparticles: 1) the precursors need to be loosely packed to avoid densification; 2)the heating time needs to be accurately controlled to tens of seconds instead of using milliseconds (thermal shock) that leads to nanoparticles or longer heating duration that forms bulk structures. The utility of the synthesized HEO microparticles for a range of applications, including high-performance Li-ion battery anode and water oxidation catalyst. This study opens up a new door toward synthesizing high-entropy microparticles with high quality and broad material space.

Electrochemical reaction mechanism of porous Zn2Ti3O8 as a high-performance pseudocapacitive anode for Li-ion batteries

Zn2Ti3O8, as a new type of anode material for lithium-ion batteries, is attracting enormous attention because of its low cost and excellent safety. Though decent capacities have been reported, the electrochemical reaction mechanism of Zn2Ti3O8 has rarely been studied. In this work, a porous Zn2Ti3O8 anode with considerably high capacity (421 mAh/g at 100 mA/g and 209 mAh/g at 5000 mA/g after 1500 cycles) was reported, which is even higher than ever reported titanium-based anodes materials including Li4Ti5O12, TiO2 and Li2ZnTi3O8. Here, for the first time, the accurate theoretical capacity of Zn2Ti3O8 was confirmed to be 266.4 mAh/g. It was also found that both intercalation reaction and pseudocapacitance contribute to the actual capacity of Zn2Ti3O8, making it possibly higher than the theoretical value. Most importantly, the porous structure of Zn2Ti3O8 not only promotes the intercalation reaction, but also induces high pseudocapacitance capacity (225.4 mAh/g), which boosts the reversible capacity. Therefore, it is the outstanding pseudocapacitance capacity of porous Zn2Ti3O8 that accounts for high actual capacity exceeding the theoretical one. This work elucidates the superiorities of porous structure and provides an example in designing high-performance electrodes for lithium-ion batteries.

Honeycomb-Like Fe3o4/Rgo Nanocomposite Powders as High-Performance Anodes for Li-Ion Batteries

Honeycomb-Like Fe3o4/Rgo Nanocomposite Powders as High-Performance Anodes for Li-Ion Batteries

An interface-enhanced continuous 2D-carbon network enabling high-performance Si anodes for Li-ion batteries

A continuous interface-enhanced 2-D carbon network is introduced in the Si anode by a templating method, which enhances the Li-ion diffusion and electron transport within the Si anode and stabilizes the interface between the Si anode and electrolyte.

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.

Synthesis of Si/Fe2O3-Anchored rGO Frameworks as High-Performance Anodes for Li-Ion Batteries.

By virtue of the high theoretical capacity of Si, Si-related materials have been developed as promising anode candidates for high-energy-density batteries. During repeated charge/discharge cycling, however, severe volumetric variation induces the pulverization and peeling of active components, causing rapid capacity decay and even development stagnation in high-capacity batteries. In this study, the Si/Fe2O3-anchored rGO framework was prepared by introducing ball milling into a melt spinning and dealloying process. As the Li-ion battery (LIB) anode, it presents a high reversible capacity of 1744.5 mAh g−1 at 200 mA g−1 after 200 cycles and 889.4 mAh g−1 at 5 A g−1 after 500 cycles. The outstanding electrochemical performance is due to the three-dimensional cross-linked porous framework with a high specific surface area, which is helpful to the transmission of ions and electrons. Moreover, with the cooperation of rGO, the volume expansion of Si is effectively alleviated, thus improving cycling stability. The work provides insights for the design and preparation of Si-based materials for high-performance LIB applications.

Conjugated Porous Polydiaminophenylsulfone-Triazine Polymer-A High-Performance Anode for Li-Ion Batteries.

Organic compounds are promising electrode materials because of their resource sustainability, environmental friendliness, and highly tailorable properties. The porous conjugated polymer shows great potential as an electrode material for its tunable redox nature, conjugated skeleton, and porous structure. Herein, a novel conjugated porous polymer, polydiaminophenylsulfone-triazine, was synthesized by a simple nucleophilic substitution reaction. The conjugated structure and triazine ring can improve the conductivity, charge-transfer efficiency, and physicochemical stability. Also, the porous polymeric framework shows a large specific surface area and high porosity, providing a large contact area with electrolytes and reducing diffusion distance. The polymer demonstrates highly stable cycling performance and good rate capability as an anode for lithium-ion batteries, suggesting a promising strategy to design a competitive electrode material.

A novel nanosheets-coated multi-layered SnO2@NiMoO4 microsphere as high-performance Li-ion battery anode

High-performance anodes are highly needed for lithium-ion batteries to achieve high capacity and energy density. Here, a strategy of combining hollow yolk-shell structure and surface modification is reported to improve the capacity of anode. As a demonstrating case study, a nanosheets-coated multiple-layered SnO2@NiMoO4 composite is prepared through a simple hydrothermal method. The results show that the multilayered SnO2 microspheres and NiMoO4 nanosheets would exhibit a synergistic effect, which efficiently improves the electrochemical properties of Li-ion battery anode. During the cycling, the hollow multilayered SnO2 microspheres coated by NiMoO4 nanosheets maintain a robust structure, and have a long cycle life. The reversible capacity of SnO2@NiMoO4 anode is as high as 1109 mAh g−1 at 400 mA g−1 for 250 cycles, which is competitive to the bare SnO2 and some other reports, indicating a potential for developing high-performance Li-ion battery systems.

Electrochemical properties of biomass-derived carbon and its composite along with Na2Ti3O7 as potential high-performance anodes for Na-ion and Li-ion batteries

Porous carbon has been synthesized from the seeds of Tamarindus indica plants at a moderately low temperature. The charge-storage property of the as-prepared carbon anode has been tested at 0.2 A g‒1 against sodium metal in half-cell and Na3V2(PO4)3 (NVP) in sodium-ion full-cell configurations and it exhibits a specific capacity of ∼162 mAh g−1 after 200 cycles and ∼164 mAh g−1 after 50 cycles respectively. Further, the composite of biocarbon with Na2Ti3O7 (NTO) has been synthesized, which shows the NTO phase transformation from monoclinic to predominantly triclinic phase during the composite preparation. The composite anode against sodium metal delivers a reversible specific capacity of 135 mAh g−1 at 0.2 A g‒1 after 250 cycles. The excellent electrochemical performance of the composite is attributed to its superior electronic conductivity, better structural stability and presence of the triclinic phase. This is supported by the first-principles density functional theory calculations, ex-situ X-ray photoelectron spectroscopy (XPS) studies and the repeated charge/discharge cycling performances. Furthermore, the performance of biocarbon anode in lithium half-cell configuration and lithium-ion full-cell configuration against LiNi0.8Co0.15Al0.05O2 (NCA) cathode has been tested and the latter shows a reversible specific capacity of ∼393 mAh g‒1 after 200 cycles at 0.2 A g‒1.

Inkjet-Printed Environmentally Friendly Graphene Film for Application as a High-Performance Anode in Li-Ion Batteries

Inkjet-Printed Environmentally Friendly Graphene Film for Application as a High-Performance Anode in Li-Ion Batteries

Achieving high-performance Li2ZnTi3O8 anode for advanced Li-ion batteries by molybdenum doping

The Li2ZnTi3-xMoxO8 (x = 0, 0.05, 0.1 and 0.15) anode materials are successfully synthesized through a simple solid-state method, and few Li2MoO4 phase can be found in Li2ZnTi3-xMoxO8 (x = 0.1 and 0.15). All samples are composed of nanocrystalline particles and irregular micron-sized particles with a relatively uniform particle size of 100–200 nm Li2ZnTi2.9Mo0.1O8 shows the best electrochemical properties among all samples. The Li2ZnTi2.9Mo0.1O8 delivers a charge/discharge capacity of 188.1/188.2 mA h/g at 1 A/g after 400 cycles, but the corresponding capacity of pristine Li2ZnTi3O8 is only 104.5 (102.2) mA h/g. The Mo6+ doping enhances the reversible capacity, rate performance, and cycling stability of Li2ZnTi3O8, especially at large current densities. The improved electrochemical performance of Li2ZnTi3-xMoxO8 can be ascribed to the enhanced electrical conductivity, improved intercalation/de-intercalation reversibility of Li ions, increased lithium-ion diffusion coefficients, and reduced charge-transfer resistance. This work provides an effective strategy to construct high-performance anode materials for advanced lithium-ion battery; this effective design strategy may be used to enhance the reversible specific capacity, and rate the performance and cycle stability of other insertion-host anode materials.

Low-cost and scalable preparation of nano-Si from photovoltaic waste silicon for high-performance Li-ion battery anode

Nano silicon (nano-Si)-based materials have been considered as promising anodes for next-generation Li-ion batteries (LIBs) because of their high specific capacity. However, a facile processing method of nano-Si with cheap Si sources is still lacking. Herein, we propose a facile, scalable and cost-effective route to produce nano-Si using a low-cost Si source from photovoltaic (PV) waste silicon. The nano-Si of 484 nm in [Formula: see text] can be easily produced using the PV waste Si by facile acid washing, heat treatment and sand milling steps. Compared with commercial nano-Si (120 nm), our low-cost nano-Si exhibits higher Coulombic efficiency (87.1%) and better cycling stability. The cycling stability of nano-Si can be obviously enhanced by using a carboxymethyl cellulose (CMC) binder and an electrolyte composed of 1 mol L[Formula: see text] LiPF6 in fluoroethylene carbonate (FEC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) (1:1:1). The nano-Si with CMC binder in 1 mol L[Formula: see text] LiPF6 FEC/EMC/DMC electrolyte could maintain a discharge capacity of 1488 mAh g[Formula: see text] after 200 cycles at 1 A g[Formula: see text]. Our work provides a promising, sustainable method to make high-performance nano-Si using a low-cost Si source.

Nb-doped Li4Ti5O12-TiO2 hierarchical microspheres as anode materials for high-performance Li-ion batteries at low temperature

Nb-doped Li4Ti5O12-TiO2 (Nb-LTO-TO) hierarchical microspheres are successfully synthesized by a facile hydrothermal route and subsequent annealing. The doping of Nb5+ enables partial reduction of Ti4+ to Ti3+, improving the conductivity of the composites and expanding the crystal lattice to increase the lithium-ion diffusion coefficient. Accordingly, Nb-LTO-TO shows a much improved low-temperature capacity compared with undoped LTO-TO when used as an anode material for Li-ion batteries. The discharge capacity of the Nb-LTO-TO composite under a current rate of 1 C reached 128.6 mAh g−1 at − 20 °C (85.8% utilization of the capacity of Nb-LTO-TO at room temperature), as well as a long-term stability of 500 cycles at a utilization of 93.9%. A discharge capacity of 119.4 mAh g−1 can still be reached at − 20 °C under a high current rate of 5 C. This encouraging performance sheds light on the design of advanced anodes for high-performance Li-ion batteries at low temperature.

Confining Nano-GeS2 in Cross-Linked Porous Carbon Networks for High-Performance and Flexible Li-Ion Battery Anodes

Confining Nano-GeS₂ in Cross-Linked Porous Carbon Networks for High-Performance and Flexible Li-Ion Battery Anodes

Constructing Densely Compacted Graphite/Si/SiO2 Ternary Composite Anodes for High-Performance Li-Ion Batteries.

Graphite has dominated the market of anode materials for lithium-ion batteries in applications such as consumer electronic devices and electric vehicles. As commercial graphite anodes are approaching their theoretical capacity, significant efforts have been dedicated towards higher capacity by blending capacity-enhancing additives (e.g., Si) with graphite particles. In spite of the improved gravimetric capacity, the areal capacity of such composite anodes might decrease due to excess void spaces and an incompatible material size distribution. Herein, a rational design of compact graphite/Si/SiO2 ternary composites has been proposed to address the abovementioned issues. Si/SiO2 clusters with an optimal particle size are homogeneously dispersed in the interstitial spaces between graphite particles to promote the packing density, leading to a higher areal capacity than that of pure graphite with equivalent mass loading or electrode thickness. By taking the full intrinsic advantages of graphite, Si, and SiO2, the composite electrodes exhibit 553.6 mAh g-1 after 700 cycles with a capacity retention of 95.2%. Furthermore, the graphite/Si/SiO2 electrodes demonstrate a high coulombic efficiency with an average of 99.68% from 2nd to 200th cycles and areal capacities above 1.75 mAh cm-2 during 200 cycles with an areal mass loading as high as 4.04 mg cm-2. A packing model has been proposed and verified by experimental investigation as a design principle of densely compacted anodes. The effective strategy of introducing Si/SiO2 clusters into the void spaces between graphite particles provides an alternative solution for implementation of graphite-Si composite anodes in next-generation Li-ion cells.

Pinecone-like Silicon@Carbon Microspheres Covered by Al2O3 nano-petals for lithium-ion battery anode under high temperature

Silicon anode has aroused ever-increasing attention for lithium ion batteries (LIBs) due to its superior features of high reversible capacity and avoidance of the fatal threat from dendrite, etc. However, silicon anode has been suffering the huge capacity degradation and poor cycle life derived from volume expansion upon lithiation/delithiation. Herein, a multi-dimensional structured engineering strategy has been adopted to generate a pinecone-like carbon microsphere filled with silicon particles, covered by Al2O3 nano-petals (Si@C@Al2O3), via a facile self-assembled method. Such a well-designed aluminum oxide and carbon coating can alleviate the volume expansion of silicon and improve electronic conductivity. The as-obtained pinecone-like Si@C@Al2O3 composites rendered an ultra-large reversible capacity of 1405 mA h g−1 at a current density of 5 A g−1 after 1000 cycles under a high temperature of 80 °C. Such an impressive performance could be ascribed to stable micro-structure and improved kinetics originating from integration effect from the covering of 2D Al2O3 nano-petals with abundant pores and compact carbon coating. Therefore, the silicon-based material is considered as a promising candidate for high-performance anodes for Li-ion batteries, especially under high temperature.

Large-scale production of highly stable silicon monoxide nanowires by radio-frequency thermal plasma as anodes for high-performance Li-ion batteries

The ideal anode materials for lithium-ion batteries require high specific capacity, excellent electrochemical stability and robust mechanical properties. Silicon nanowires (Si NWs) may be a suitable anode material. However, the anisotropic expansion of Si NWs depending on crystallographic orientation frequently leads to their fractures and poor stability. Herein, amorphous silicon monoxide (SiO) NWs with Si as the head (SiO/Si NWs) are predicted and mass (120 g h−1) synthesized by using a radio-frequency (RF) plasma system. Owing to the unique one-dimensional (1D) nanostructures with homogeneous Li+ insertion and isotropic expansion, the SiO/Si NWs exhibited excellent electrochemical performance. And the SiO/Si NWs with multiple reaction sites and short diffusion length possessed significant pseudocapacitive properties. Moreover, the uniform and meager volume expansion (~40%), excellent structural stability and superior tenacity of SiO/Si NWs are directly observed by in-situ transmission electron microscope (TEM). Subsequently, the vertical graphene-like carbon encapsulation of SiO/Si NWs (SiO/Si/C NWs) is prepared by chemical vapor deposition (CVD) process. As anodes, SiO/Si/C NWs show an ultra-stable capacity of 650 m Ah g−1 for 1000 cycles even at 2.0 C, manifesting great promise for the forthcoming industrialized high-performance batteries.

Silicon nanoparticles encapsulated in multifunctional crosslinked nano-silica/carbon hybrid matrix as a high-performance anode for Li-ion batteries

• A novel multifunctional nano-silica/carbon hybrid matrix is designed to encapsulate Si nanoparticles in the coating layer. • The n-SiO 2 /C layer is applied to enhance the conductivity, hold the structural integrity, and provides a higher capacity. • The Si-2@n-SiO 2 /C composites demonstrate ideal cycle stability as anode material for lithium-ion batteries. The application of silicon as anode materials for lithium-ion batteries is limited by the huge volumetric expansion and complex synthesis processes. Herein, silicon nanoparticles encapsulated in multifunctional crosslinked nano-silica/carbon hybrid matrix (Si@n-SiO 2 /C) composites are successfully synthesized via simultaneous condensation copolymerization between (3-aminopropyl)-triethoxysilane (APTES) and L-ascorbic acid (L-AA). With the introduction of nano-silica, the multifunctional nano-silica/carbon hybrid matrix can significantly maintain structural integrity during the volume change of silicon, provide a higher capacity than the traditional single carbon coating layer and enhance the conductivity of the materials. Correspondingly, the obtained Si-2@n-SiO 2 /C composites display quite outstanding cycle stability and superior structural integrity maintenance, which delivers a capacity of 800.7 mAh g −1 after 300 cycles at the current density of 1 A g −1 . Such a novel coating layer structure design and simultaneous growth of nano-silica/carbon hybrid matrix layer on silicon nanoparticles will provide a simple synthesis strategy for manufacturing high-performance Si-based anode materials.