High-performance Lithium-ion Battery Anodes Research Articles

Ultrathin CoOOH/Co(OH)2 hybrid nanosheets for high-performance anodes of lithium-ion batteries

CoOOH and Co(OH)2 have great potential in lithium-ion battery anodes due to their high theoretical specific capacities. But they suffer from large volume change during the cycle and hence display fast capacity fading. Carbon coated ultrathin two-dimensional porous nanostructure engineering can be conducive to improving cycling stability of both CoOOH and Co(OH)2, but it is a huge challenge. Herein, a tetraethyl orthosilicate (TEOS) assisted synthesis of carbon coated ultrathin porous CoOOH/Co(OH)2 hybrid nanosheets (COH@C NSs) has been proposed and achieved successfully. This original idea using the TEOS as the reactant not only constructs the ultrathin two-dimensional nanosheets as a structure directing reagent but also forms a porous structure as a precursor of SiO2 pore templates. As a result, the COH@C NSs integrate the advantages of ultrathin two-dimensional nanosheets, porous structure and carbon coating, and hence have significantly improved structural stability and electrochemical kinetics during the cycle, delivering 845.3 mA h g−1 in 350th cycle at 200 mA g−1 and 696.2 mA h g−1 in 400th cycle at 1000 mA g−1. This work gives a unique insight for engineering ultrathin two-dimensional porous nanostructure of high-capacity CoOOH/Co(OH)2 hybrid electrode.

QPHT graphene as a high-performance lithium ion battery anode materials with low diffusion barrier and high capacity

In past two decades, scientists have worked to find battery anode materials with high lithium storage capacity and good electrical conductivity to better solve the problems of environmental protection, cleanliness and sustainable energy. In this manuscript, we choose a novel two-dimensional carbon material that can exist stably at room temperature — QPHT graphene, as the research object. By employing first-principles calculations, we investigated the diffusion barrier and open circuit voltage of QPHT graphene. Similar to graphene, QPHT graphene has a relatively low lithium diffusion potential barrier (<0.83 eV), high lithium storage capacity (837 mAh/g) and average open circuit voltage (0.66 V), making it an auspicious anode material for fast charge/discharge lithium ion battery. The present study is essential for exploring the application of novel graphene in lithium ion battery anode materials.

Electrochemical Synthesis of Binary Structured Clusters Based on Si Nanoparticles and Si Nanowires for High-Performance Lithium-Ion Battery Anodes

Electrochemical Synthesis of Binary Structured Clusters Based on Si Nanoparticles and Si Nanowires for High-Performance Lithium-Ion Battery Anodes

Synthetic Strategy of Si@void@C Nanoparticles for High-Performance Lithium-Ion Battery Anodes

Synthetic Strategy of Si@void@C Nanoparticles for High-Performance Lithium-Ion Battery Anodes

Retraction: Co3 O4 Polyhedron@MnO2 Nanotube Composite as Anode for High-Performance Lithium-Ion Batteries.

Small 2021, 17, 2008165 DOI: 10.1002/smll.202008165 The above article in Small, published online on 26 March 2021 in Wiley Online Library (https://onlinelibrary.wiley.com/doi/abs/10.1002/smll.202008165),[1] has been retracted by agreement between the authors, the Editor-in-Chief, José Oliveira, and Wiley-VCH GmbH. The retraction has been agreed following an investigation by the corresponding author. The electrochemical measurements on the anode were performed in a wrong manner and cannot reliably be reproduced. The conclusions of this article are considered to be invalid. The authors agree with the retraction but were not available to confirm the final wording of the retraction. [1] Z. Cao, Y. Yang, J. Qin, J. He, Z. Su, Small 2021, 17, 2008165.

Self-supported hollow-Co3O4@CNT: A versatile anode and cathode host material for high-performance lithium-ion and lithium-sulfur batteries

Inferior specific capacity and sluggish redox kinetics are the most stubborn problems lithium-ion and lithium-sulfur batteries (LIBs and LSBs) are facing, respectively. Here we report a facile fabrication of self-supported hollow Co 3 O 4 @carbon nanotubes on carbon cloth (H-Co 3 O 4 @CNT/CC) through a mild pyrolysis-oxidation process. The additive- and binder-free H-Co 3 O 4 @CNT/CC shows excellent electrochemical performances as both LIBs and LSBs electrodes. As a robust integrated anode for LIBs, the areal capacities are 2.72 mAh cm −2 at the current density of 0.5 C over 1000 cycles. While as a durable cathode host for LSBs, favorable areal capacities of 2.37 mAh cm −2 are maintained with a low capacity decay of 0.11 % per cycle at the sulfur loading of 6 mg cm −2 and current density of 1 C after 400 cycles. Electrochemical technology, ex situ Raman spectroscopy and DFT calculations are performed to comprehensively analyze H-Co 3 O 4 @CNT/CC via thermodynamics and kinetics. It is demonstrated that the hierarchically hollow interior structure, strong adsorb ability of Co 3 O 4 toward polysulfides and three-dimensional (3D) inter-connected conductive carbon framework are responsible for the high areal capacity, fast redox kinetics and cycling durability. The synergistic effect of different components and structures of hollow-Co 3 O 4 @CNT, which have internal hollow structure, incorporation of Co 3 O 4 into elastic buffering framework and high porosity, contributes greatly to the superior electrochemical performances in terms of high areal capacity, good rate capability and ultralong cycling stability. • The integrated electrode possesses the merits of hollow nanostructured Co 3 O 4 and 3D inter-connected conductive network. • Electrochemical technology and DFT calculations are performed to comprehensively analyze H-Co 3 O 4 @CNT/CC. • H-Co 3 O 4 @CNT/CC delivers high areal capacities of 2.72 mAh cm -2 after 1000 cycles at 0.5 C as anode.

Electrospinning fabrication of Sb-SnSb/TiO2@CNFs composite nanofibers as high-performance anodes for lithium-ion batteries

The SnSb and TiO2 nanoparticles uniformly embedded into continuous and conductive carbon nanofibers (CNFs) are successfully fabricated through facile electrospinning combined with calcination treatments. The characterization results of the targeted composite nanofibers (Sb-SnSb/TiO2@CNFs-2) confirm that the presence of TiO2 is of significant importance to construct the elaborately designed and intact fiber structure, in which the optimal dosage of the TiO2 precursor is precisely controlled at 2 mmol. Moreover, high theoretical specific capacity of SnSb, available inhibitory effect of TiO2, and great electronic conductivity of CNFs are cooperatively integrated into the Sb-SnSb/TiO2@CNFs-2 composite nanofibers, guaranteeing the enhanced lithium storage capacity and cycling performance when being employed as the anode electrodes. Specifically, the Sb-SnSb/TiO2@CNFs-2 electrode can not only deliver initial discharge specific capacity of 1146.6 mAh/g at 100 mA/g and reversible discharge specific capacity of 580.4 mAh/g after 100 cycles, but also retain discharge specific capacity of 561.3 mAh/g after rate cycles along with recovering the current density to 100 mA/g. Importantly, the Sb-SnSb/TiO2@CNFs-2 electrode is also endowed with prominent advantages in the pseudocapacitive contribution of 66.89 % at 0.8 mV/s. Those investigations and findings of the Sb-SnSb/TiO2@CNFs-2 composite electrodes with facile fabrication process and excellent electrochemical performance can contribute to the practical application of the alloy anodes in the field of the energy storage.

Nanowires-Assembled TiO2 Nanorods Anchored on Multilayer Graphene for High-Performance Anodes of Lithium-Ion Batteries.

Multilayer graphene (MLG) prepared via ultrasonic exfoliation has many advantages such as its low-cost and defect-free nature, high electronic conductivity, and large specific surface area, which make it an apt conductive substrate for TiO2 composites. To synthesize graphene/TiO2 hybrids, traditional methods that greatly depend on the chemical bond of oxygen-containing functional groups on graphene with titanium cations are not applicable due to the absence of these functional groups on MLG. In this work, a facile chemical method is developed to directly deposit TiO2 on the MLG surface without the introduction of chemically active groups. With this method, four types of TiO2 materials, that is pure anatase TiO2 nanoparticles, a mixture of anatase TiO2 nanoparticles and rutile TiO2 nanoflowers, pure rutile TiO2 nanoflowers, and pure rutile TiO2 nanorods, are homogeneously anchored on the MLG surface by controlling the amount of HCl in the reactant. Interestingly, the rutile TiO2 nanorods in the TiO2/MLG composite are assembled by many TiO2 nanowires with an ultra-small diameter and ultra-long length, which provides a better synergetic effect for high performances as LIB anodes than other composites. A specific capacity of 631.4 mAh g−1 after 100 cycles at a current density of 100 mA g−1 is delivered, indicating it to be a valuable LIB anode material with low cost and high electrochemical performances.

Two-dimensional porous β-Co(OH)2 and Co3O4 hexagonal nanoplates as stable and high-performance anode for lithium-ion batteries

The multifunctional β-Co(OH)2 and Co3O4 nanoplates were successfully synthesized using a silicone oil-bath method, which manifests hexagonal-like structures with the existence of interior pores. The two-dimensional (2D) porous β-Co(OH)2 and Co3O4 hexagonal nanoplates (HNPs) were obtained at the reaction temperatures of 80 °C (β-Co(OH)2@80) and 100 °C (Co3O4@100), further calcined at 450 °C. The specific surface areas of 59.6 and 101.8 m2 g−1 were obtained for the β-Co(OH)2 and Co3O4@100 HNPs samples, respectively. Both the samples were utilized as anodes for lithium (Li)-ion batteries. The 2D porous Co3O4@100 HNPs electrode delivered an excellent discharge capacity of 1141 mA h g−1 at 100 mA g−1, whereas 506 mA h g−1 remained for the β-Co(OH)2@80 HNPs electrode. Additionally, the Co3O4@100 HNPs electrode was sustained over 1000 cycles with a discharge capacity of 566 mA h g−1. Furthermore, the Co3O4@100 HNPs electrode showed good rate performance with a discharge capacity of 458 mA h g−1 even at 800 mA g−1. The obtained excellent electrochemical characteristics of Co3O4 electrodes are ascribed to the unique 2D structure with small-sized interior pores, which facilitates Li+ diffusion and enhances structural robustness.

Graphene supported double-layer carbon encapsulated silicon for high-performance lithium-ion battery anode materials

Carbon coating has been an effective procedure to tackle the severe structural degradation and poor conductivity during cycling of silicon-based anodes in lithium-ion batteries (LIBs). However, the traditional coated carbon usually is tight and thus limit the fast-charging rate and high specific capacity. Herein, through in-situ formation of metal-organic frameworks on the surface, silicon particles were firstly coated by an inside carbon layer. Followed by a solvothermal reaction with the mixture of sucrose and graphene oxide, the second carbon layer outside the silicon particles was deposited, and simultaneously a highly conductive graphene network was formed. After a high temperature pyrolysis process, a graphene matrix supported silicon material with inward multi-channel carbon and outward tight activated carbon was prepared. This unique core/double-layer carbon structure, combined with the highly conductive graphene frameworks, render the material to demonstrate excellent electrochemical performance as anode materials for LIBs in terms of both lithium storage capacity and cycling stability. Thus, the electrode materials deliver a high specific capacity of 1528.1 mA h g−1 at the current density of 0.1 A g−1 and rate capacity retention of 45.5% at 1 A g−1 to 0.1 A g−1. Simultaneously, a highly stable reversible capacity of 1182 mAh g−1 with 89.5% retention over 240 cycles at a current density of 0.2 A g−1 and 484 mAh g−1 with 76.8% retention after 450 cycles at 1.0 A g−1 were obtained. This work can offer an alternative approach for high-energy and low-cost silicon-based anodes for LIBs.

Coal-derived graphene foam and micron-sized silicon composite anodes for lithium-ion batteries

Silicon-based materials demonstrate significant potential as lithium-ion batteries (LIBs) anode, but their expansion and degradation present engineering design challenges for commercial application. In this study, a porous three-dimensional (3D) graphene and micron-sized silicon composite anode (Si@G foam) was synthesized using humic acid (HA) derived from coal as a graphene precursor. In-situ formation of graphene structure through reducing HA was confirmed by Raman spectra. The reduced HA (rHA) shows similar electrical conductivity compared to the commercial conductive carbon. SEM images depict a 3D skeleton of coal-derived graphene, with silicon particles distributed on the 3D graphene foam's internal surface. The Si@G composite-anode displays a good reversible capacity of ∼656 mAh/g at a current density of 50 mA/g, as well as a high-rate capability of ∼433 mAh/g at a current density of 800 mA/g, and outstanding cycling stability –89.8% capacity retention after 300 cycles, which is significantly higher than that of other foam structures. During lithiation and de-lithiation, the graphene foam serves as a matrix of electrical conductors and a volume expansion support for silicon. This 3D graphene network will be beneficial for developing advanced silicon-based anodes for high-performance LIBs.

High-performance and flexible lithium-ion battery anodes using modified buckypaper

Conventional electrodes for lithium ion batteries, represented as the electrode films casted on the metal foil, are struggling to fulfill the requirements for the flexible electronics due to their heavy, thick, rigid, and brittle structure, which can lead to the deterioration of electrical contact followed by low cycling stability under the repeating mechanical stress. Therefore, development of stable and flexible electrodes is of crucial demand for the implementation of lithium ion batteries to the flexible electronic devices. In this study we demonstrate that the flexible and light buckypaper with high electrical conductivity is the promising alternative to the metal current collectors. In addition, the high capacity anode based on SiO2 nanoparticles is introduced to the functionalized buckypaper. Our electrode reveals high energy storage capability (1101 mAh/g) even after 300 cycles. The composite electrode can be considered the potential high-performance anode for flexible electronic devices.

Drop-casting preparation of a binder-free SiOx anode with micron-sized SiOx particles for high-performance lithium-ion batteries

Sub-valent silicon oxide (SiO x ) is a promising next-generation anode material in lithium-ion batteries. However, SiO x still suffers large volume expansion during the lithiation, resulting in deteriorated battery performance. Herein, we report a low-cost and easy-to-scale-up method to prepare a SiO x -based anode (named as SiO x @G-Ni) by drop-casting the slurry of asphalt, micron-sized SiO x powder, nickel salt and carbon nanotubes onto a Cu foil and subsequent thermal pyrolysis. The obtained electrode consists of a rigid graphenic carbon network that is embedded with micron-sized SiO x , nickel nanoparticles and carbon nanotubes. The SiO x @G-Ni electrode delivers a specific charge capacity of 1061 mA h g −1 at 0.08 A g −1 , and a capacity retention rate of 86.7 % after cycled 500 times at 1.6 A g −1 . The full battery SiO x @G-Ni||LiCoO 2 reaches a capacity retention rate of 79.3 % after 250 cycles at 0.5 C. The method employed in this work could be used for the preparation of the SiO x -based anode for high-performance lithium-ion batteries. • Preparation of binder-free micron-sized SiO x electrodes by drop-casting method. • Utilize the catalytic effect of nickel particles to form a multilayer graphenic network. • The SiOx@G-Ni electrode delivers great half-cell and full-cell cycle performance.

Nano tin encapsulated in copper grooves as an anode for high-performance lithium-ion batteries

With the ever-growing demand for high energy and power density lithium-ion batteries (LIBs), tin (Sn) has been considered a capable anode material because of its high theoretical capacity (993.4 mAh/g). However, the practical application of Sn anodes suffers from low capacity retention due to significant volume expansion (~257 %) and poor ion and electron transportation during cycling. To overcome these problems, a novel architecture is necessary to mitigate volume expansion during cycling without instigating severe electrode fragmentation. In this work, we developed grooves on a copper plate (25 µm thickness) by etching it with SiC sandpaper of different grain sizes (23 µm (#400), 68 µm (#220), and 190 µm (#80)). The Sn (60–70 nm) was inserted in the developed grooves of the copper plate (Sn/Cu) and coated with polyvinylidene fluoride (PVDF) to form a confined structure. The PVDF-coated Sn/Cu plates (#400, #220, and #80) were used as anode materials for LIBs. The prepared electrodes delivered high capacities of 274, 153.7, and 103 mAh/g after 500 cycles at a 0.2 C-rate. The present work opens a novel path for fabricating high-performance LIBs using a simple experimental process.

Embedding silicon in biomass-derived porous carbon framework as high-performance anode of lithium-ion batteries

Silicon (Si) is regarded as a promising anode material for lithium-ion batteries because of its ultrahigh theoretical specific capacity, appropriate potential, and abundant resources. However, its inherent insulation and large volume changes lead to inferior electrochemical activity and unsatisfactory cycling stability, thus limiting its practical applications. In this study, a grape stem-derived porous carbon framework (PCF) with slender through-holes in the interior and a large number of micropores on the carbon walls was prepared via a facile approach and employed as the Si matrix. The continuous through-holes and well-distributed oxygen-containing functional groups of the PCF provided the Si nanoparticles with sufficient space to accommodate volumetric expansion and abundant active sites for adsorption. Additionally, the porous structure and high conductivity of the PCF facilitated electrolyte penetration and electron transfer. Therefore, the PCF/Si composite exhibited a decent discharge capacity (1006 mA h g−1 at 0.2 A g−1) and robust cycling stability (891 mAh g−1 remaining after 400 cycles).

Three-dimensional network of nitrogen-doped carbon matrix-encapsulated Si nanoparticles/carbon nanofibers hybrids for lithium-ion battery anodes with excellent capability.

Three-dimensionally structured silicon (Si)–carbon (C) nanocomposites have great potential as anodes in lithium-ion batteries (LIBs). Here, we report a Nitrogen-doped graphene/carbon-encapsulated Si nanoparticle/carbon nanofiber composite (NG/C@Si/CNF) prepared by methods of surface modification, electrostatic self-assembly, cross-linking with heat treatment, and further carbonization as a potential high-performance anode for LIBs. The N-doped C matrix wrapped around Si nanoparticles improved the electrical conductivity of the composites and buffered the volume change of Si nanoparticles during lithiation/delithiation. Uniformly dispersed CNF in composites acted as conductive networks for the fast transport of ions and electrons. The entire tightly connected organic material of NG/C@Si and CNF prevented the crushing and shedding of particles and maintained the integrity of the electrode structure. The NG/C@Si/CNF composite exhibited better rate capability and cycling performance compared with the other electrode materials. After 100 cycles, the electrode maintained a high reversible specific capacity of 1371.4 mAh/g.

Solvent-free and large-scale synthesis of SiOx/C nanocomposite with carbon encapsulation for high-performance lithium-ion battery anodes

High-capacity SiOx anodes are fatally limited by poor electrical conductivity and huge volume fluctuations. Nano-engineering can effectively extend battery life, but achieving the transformation of nanostructures from laboratory synthesis to industrial mass production still remains a great challenge. Conventional synthetic routes are plagued by harsh conditions, complex processes, and especially low yields; even if they are adopted by industrial production, the large amounts of solvents in traditional wet chemical methods will pose a potential risk of pollution and energy waste. Herein, a solvent-free and mass-producible strategy is presented to prepare SiOx/C@C nanocomposite via solvent-free sol-gel, ball milling, and carbon coating process. The production exhibits favorable powder properties for conventional LIB fabrication technology, such as narrow particle size distribution, suitable specific surface area, as well as a high yield (40.5%). The prepared SiOx/C@C anode displays a high initial coulombic efficiency (71.4%) and reversible capacity (1279 mAh g−1 at 0.1 A g−1), and a great durability (80.08% capacity retention after 1000 cycles at 1.0 A g−1). Furthermore, the superior matching performance of SiOx/C@C//LiCoO2 full-cell is also clearly demonstrated, especially the high energy density (347 Wh kg−1). This ingenious and scalable strategy will remarkably promote the commercialization of nanostructures.

Multi-buffer engineering of nitrogen-doped carbon nanosheets/carbon nanotubes network encapsulated and carbon coated silicon anode for high performance lithium-ion batteries

The commercial application of silicon (Si) anode is still hindered by unfavorable phenomena such as huge volume expansion, low intrinsic conductivity and unstable solid electrolyte interface film of Si during cycling. Developing a simple and scalable synthesis for multi-buffer engineering with different carbon structures is significant and challenging for the commercial prospects of Si anode. Herein, we propose a multi-buffer engineering strategy with nitrogen-doped carbon nanosheets/carbon nanotubes network encapsulated and carbon-coated Si hybrid structure (Si@C@N-CNs/CNTs) via an efficient and convenient resin coating followed by in-situ catalytic pyrolysis of melamine and paraffin oil. The designed Si@C@N-CNs/CNTs delivers high discharge capacity (2950.6 mAh g−1 at 0.4 A g−1), good cyclability (1017.4 mAh g−1 after 350 cycles), and outstanding rate performance (1068.5 mAh g−1 at 8 A g−1). The electrochemical kinetics and structural stability test results demonstrate such superior performance is originated from the multi-buffer engineering by the 3D conductive N-CNs/CNTs networks, carbon coated layer and fine dispersed CoSi2 nanoparticles, which can provide fast electron and ion transfer, effective volume buffer effect and excellent structural stability. Direct comparison with other two Si anodes reveals the significance of the multi-buffering synergistic effect and its great potential in application of high-performance anode for lithium-ion batteries.

Controllable self-assembled flower-like FeS with N-doped carbon coating anchored on S-doped reduced graphene oxide as high-performance lithium-ion battery anode

Iron sulfide (FeS) was supposed to be a suitable substitute for the commonly used graphite anode in lithium-ion batteries due to its higher specific capacity. However, its electrochemical property was severely limited due to its weak conductivity and evident volume change. To address these issues, we successfully construct controllable self-assembled flower-like with N-doped carbon coating FeS anchored on S-doped reduced graphene oxide (FeS/C@rGO) nanocomposites, used the synthesized octahedron iron-based metal-organic framework and graphene oxide composite (Fe-MOF@GO) as the precursor and thioacetamide as the sulfur via high-temperature calcination. The flower-like structure was generated by the controllable self-assembly of FeS nanosheets following an octahedral collapse, which enhanced the contact area between the active material and the electrolyte and improved Li+ transmission efficiency. Furthermore, the N-doped carbon and rGO efficiently inhibits the volume growth and aggregation of FeS nanosheets, resulting in the fabrication of controllable self-assembled flower-like FeS/C@rGO with a stable structure and outstanding rate performance. The discharge capacities of the FeS/C@rGO electrode were 1446.3, 1379.4, 1266.7, 1179.2, 1097.5 and 980.7 mAh g−1 at different current densities of 0.1, 0.2, 0.5, 1.0, 2.0 and 5.0 A g−1, respectively. When the current density returns to 0.1 A g−1, the reversible capacity is restored to 1629.7 mAh g−1. Moreover, the reversible specific capacity of FeS/C@rGO anode was 1428.2 mAh g−1 (130 cycles) at 0.1 A g−1 current density, showing excellent cycling performance.

Facile fabrication of Si-embedded amorphous carbon@graphitic carbon composite microspheres via spray drying as high-performance lithium-ion battery anodes

Silicon-nanoparticle-embedded amorphous carbon-graphitic carbon composite microspheres (denoted as Si/AC@GC) with numerous empty voids are synthesized using a spray drying process. Spray dried composite microspheres consisting of Si nanopowders, dextrin, and iron salt are transformed to uniquely structured Si/AC@GC microspheres via one-step carbonization followed by acid etching. The in situ formation of graphitic carbon with high electrical conductivity within the Si-C composite at a low carbonization temperature (700 °C) is achieved by applying a metallic Fe nanocatalyst. The Si/AC@GC microspheres exhibit higher electrochemical properties than bare Si nanopowders and Si/amorphous carbon composite microspheres (denoted as Si/AC) with filled structures. The synergistic effects of structural merits owing to the spherical morphology with empty nanovoids for liquid electrolyte penetration and a graphitic carbon layer with high electrical conductivity result in the superior lithium-ion storage performances of Si/AC@GC microsphere. The composite-based electrode delivers a high reversible capacity of 803 mA h g−1 after 200 cycles at 1.0 A g−1, indicating long-term cycling stability. Even at 5.0 A g−1, the electrode exhibits stable reversible discharge capacity of 589 mA h g−1 without significant capacity loss.