Anode For Li-ion Batteries Research Articles

Candle soot-metal-organic framework-based hierarchical electrode as high-performance anode for Li-ion batteries

Recently, cobalt oxide-based materials have been considered high-performance anode materials. However, cobalt oxide materials display drawbacks such as capacity fade, poor cycle life, and substantial structural strain. In this work, we report a facile synthesis of carbon-cobalt oxide composite to improve the electrode's storage capabilities and cycle life. First, metal–organic framework-based cobalt oxide nano leaves are synthesized by simple coprecipitation followed by calcination. After that, candle soot-derived carbon nanoparticles are uniformly deposited on the cobalt oxide nano leaves by a simple flame synthesis method to form a composite electrode. The fractal-like interconnected carbon nanoparticles improve the electron conducting pathways. In contrast, metal–organic framework-derived porous cobalt oxide nano leaves enhance energy storage abilities through reversible conversion reactions. The superior performance of the composite electrode is established from the galvanostatic charge–discharge experiments. Also, the composite electrode has delivered outstanding specific capacities of 811 and 503 mAh g−1 at 50 and 1000 mA g−1 current densities, respectively. Furthermore, the composite electrode exhibited good cyclic stability at 1000 mA g−1 current density by delivering an excellent specific charge capacity of 490 mAh g−1 even after 400 cycles. Therefore, these superior electrochemical properties confirm the potential applicability in high-performance and stable Li-ion batteries.

Design and Performance of a New Zn0.5Mg0.5FeMnO4 Porous Spinel as Anode Material for Li-Ion Batteries.

Due to the low capacity, low working potential, and lithium coating at fast charging rates of graphite material as an anode for Li-ion batteries (LIBs), it is necessary to develop novel anode materials for LIBs with higher capacity, excellent electrochemical stability, and good safety. Among different transition-metal oxides, AB2O4 spinel oxides are promising anode materials for LIBs due to their high theoretical capacities, environmental friendliness, high abundance, and low cost. In this work, a novel, porous Zn0.5Mg0.5FeMnO4 spinel oxide was successfully prepared via the sol-gel method and then studied as an anode material for Li-ion batteries (LIBs). Its crystal structure, morphology, and electrochemical properties were, respectively, analyzed through X-ray diffraction, high-resolution scanning electron microscopy, and cyclic voltammetry/galvanostatic discharge/charge measurements. From the X-ray diffraction, Zn0.5Mg0.5FeMnO4 spinel oxide was found to crystallize in the cubic structure with Fd3¯m symmetry. However, the Zn0.5Mg0.5FeMnO4 spinel oxide exhibited a porous morphology formed by interconnected 3D nanoparticles. The porous Zn0.5Mg0.5FeMnO4 anode showed good cycling stability in its capacity during the initial 40 cycles with a retention capacity of 484.1 mAh g-1 after 40 cycles at a current density of 150 mA g-1, followed by a gradual decrease in the range of 40-80 cycles, which led to reaching a specific capacity close to 300.0 mAh g-1 after 80 cycles. The electrochemical reactions of the lithiation/delithiation processes and the lithium-ion storage mechanism are discussed and extracted from the cyclic voltammetry curves.

Preparation of various Co/Cu and Co/Fe molar ratios and gel-modified nanomaterials as anodes for Li-ion batteries

Co-based binary metal oxides with higher theoretical capacity have attracted increasing attention as anodes for lithium-ion batteries (LIBs). In this study, Co-based bimetallic oxides were prepared by optimizing different molar ratios of Cu/Co and Fe/Co using an electroconversion method. The purity and microstructure of the synthesized powders were investigated, and their lithium storage properties were studied by assembling half-cells. Cu/Co oxide exhibited three different microstructures, while Fe/Co oxide showed a nanoparticle morphology. The electrochemical performance results revealed that the optimal molar ratio of Co: Cu was 2:1, and the optimal molar ratio of Fe: Cu was 5:1. Particularly, Fe: Cu = 5:1 exhibited the best electrochemical stability and higher specific capacitance. Therefore, Fe3O4/Co3O4 (Fe: Cu = 5:1) was used as the raw material for modification, and a hydrogel method was employed with sodium alginate (SA) serving as the fixing agent and carbon source to prepare microspheres. Taking advantage of the natural freezing conditions in the winter of Northeast China, the dried microspheres were subjected to calcination to obtain Fe3O4/Co3O4/SA with enhanced conductivity. Even at a current density of 2 A/g, Fe3O4/Co3O4/SA still maintained a discharge capacity of around 280 mAh/g, demonstrating excellent cycling stability and rate capability.

Ab initio study of Li-shrouded Si-doped [formula omitted]-Graphyne nanosheet as propitious anode in Li-ion batteries

Li-ion batteries (LIBs) have become a house-hold name in the energy-storage research community in the wake of their noteworthy attributes. With increasing energy demands, the urgency to develop high performance LIBs is also rising rapidly which has compelled the researchers to design and fabricate new high capacity materials. Bearing that in mind, we have investigated a carbon–silicon based anode, i.e. Si-doped γ-Graphyne (SiG) nanolayer for its applicability as LIB electrode. Carbon and Silicon are two complementary choices for anode material due to the reason that the weakness of one is complemented by the other i.e. the extensive volume changes of Si anodes is compensated by the stable carbon matrix and the lower Li affinity of carbon is complemented by large capacities of Si anode. The Density Functional Theory (DFT) based studies reveal that SiG nanolayer has a dynamically and thermally stable structure with reliable mechanical properties. Density of states (DOS) calculation substantiates the good conductivity of the nanolayer. The binding energy of the Li atom (adatom) is −1.33 eV resulting from a charge transfer of 0.88e from Li to the nanolayer. The SiG anode achieved a specific capacity of 1005.05 mAhg−1 (almost 2.7 times the Graphite anode used in commercial LIBs). Climbing Image-Nudged Elastic Band (CI-NEB) calculations depict an easy migration of the adatoms through the anode with an energy barrier of 0.67 eV having diffusion coefficient (D) as 8.91 × 10−14 cm2/s. A low working voltage of 0.44 V is obtained advocating a safe operation and good cyclability. So, the theoretical investigation presents favorable outcomes for Si-doped γ-Graphyne to be applicable as a progressive anode in next-generation LIBs.

Thermal polymerization of ion-modified carbon dots into multi-functional LiF-carbon interface for stabilizing SiO anode

SiO has been demonstrated as one type of promising high-capacity anode for Li-ion batteries. However, the parasitic reactions between the electrolyte and SiO interface, severer than that of the well-developed graphite, are generally overlook. Herein, a multi-functional LiF-carbon co-coating layer on SiO (SiO@LCD) is designed to resist the interfacial reactions, which originates from thermal-assembly of zero-dimensional Li-absorbed and F-doped carbon dots produced by hydro/alcohol-thermal reaction of discarded wood sawdust with a high yield of 96.9 %. Combined with advanced spectroscopy characterizations and theoretical calculations, the LiF-carbon co-coating layer has been determined to induce preferential decomposition of LiPF6 to form a thin and dense solid electrolyte interface (SEI) with LiF-rich inner layer, and promote the rapid transmission of ion/electron. As a result, the initial Coulombic efficiency (CE) of the SiO@LCD increases from 66.1 % to 78.6 %, and the average CE is increased by 0.3 % at 0.2 A g−1 with enhanced rate capability and cycling stability during the (de)lithiation process. More importantly, the assembled 3.7 Ah pouch cell exhibits a long-term cycling life over 400 cycles at 0.2 C with the capacity retention of 85.1 %.

Eco-saving and green anode materials for Li-ion batteries utilizing oxide-decorated biocarbon substrates proceeded from cassava residues

In this work, an eco-saving and green anode structure (CRC) of MnO/Mn3O4 nanoparticles (NPs) anchored on biocarbon substrates derived from cassava residues (CRs) was designed and fabricated successfully by an in-situ method from MnCl2 and CRs. The amount of MnO/Mn3O4 NPs in the CRC can be effectively modulated by altering the mass ratio of MnCl2 to CRs. In Li-ion batteries, CRC anodes exhibit outstanding electrochemical performances such as high Coulombic efficiency, high capacity, excellent rate capacity, and stable cycling. The high reversible capacity of 698 mAh g−1 at 100 mA g−1 can be achieved even after 100 cycles. This could be accredited to the special structure of MnO/Mn3O4 NPs and biocarbon substrates. First, CR-derived biocarbon favors the alleviation of volume change and prevents the aggregation of MnO/Mn3O4 NPs during cycling. Then, an appropriate amount of MnO/Mn3O4 NPs formed on the surface and empty cages of biocarbon generate various free contacting channels between the electrolyte and active materials. Finally, MnO/Mn3O4 NPs intensify the electrochemical activity of biocarbon, leading to an increase in Li-storage capacities. Therefore, the facile in-situ method in this work is quite promising to produce cost-effective and eco-friendly anodes for Li-ion batteries utilizing recycled CRs and simple chemicals.

Freestanding and Consecutive Intermixed N-Doped Hard Carbon@Soft Carbon Fiber Architectures as Ultrastable Anodes for High-Performance Li-Ion Batteries

Freestanding and Consecutive Intermixed N-Doped Hard Carbon@Soft Carbon Fiber Architectures as Ultrastable Anodes for High-Performance Li-Ion Batteries

MnNCN@C nanocomposite as an anode for Li-ion battery

In order to find other anode materials for lithium-ion batteries, manganese carbodiimide with N-doped C coating (MnNCN@C) has been reported. Initially a gel of precursors was prepared and then calcined for 1.5 h at 700 °C in the atmosphere of N2. The MnNCN phase was identified by X-ray diffraction, X-ray Photoelectron Spectroscopy (XPS) and electron diffraction. Further, carbon phase was established by transmission electron microscopy (TEM), FTIR and Raman spectroscopy. The doping of N in carbon phase was confirmed from XPS study. Distribution of pore size as well as specific surface area of MnNCN@C composites were investigated from the BET technique, and their values were 9.19 × 103cm2/g and 7.512 nm, respectively. The cell with this material as anode could be cycled for 100 times. After 100 cycles, the capacity turns out to be around 200 mAh/g. However, the cell was capable to deliver suitable capacity at even higher currents.

NbO2 a Highly Stable, Ultrafast Anode Material for Li- and Na-Ion Batteries.

Anode materials with fast charging capabilities and stability are critical for realizing next-generation Li-ion batteries (LIBs) and Na-ion batteries (SIBs). The present work employs a simple synthetic strategy to obtain NbO2 and studies its applications as an anode for LIB and SIB. In the case of the LIB, it exhibited a specific capacity of 344 mAh g-1 at 100 mA g-1. It also demonstrated remarkable stability over 1000 cycles, with 92% capacity retention. Additionally, it showed a unique fast charging capability, which takes 30 s to reach a specific capacity of 83 mAh g-1. For the SIB, NbO2 exhibited a specific capacity of 244 mAh g-1 at 50 mA g-1 and showed 70% capacity retention after 500 cycles. Furthermore, detailed density functional theory reveals that various factors like bulk and surface charging processes, lower ion diffusion energy barriers, and superior electronic conductivity of NbO2 are responsible for the observed battery performances.

Selenium enriched over-oxidized Mo3Se4 decorated MXene as a high-performance Li-ion battery anode material

The anode materials in Li-ion battery (LIB) are key components that define the performance of the cell. We have developed new selenium enriched and over-oxidized Mo3Se4 decorated MXene (Mo3Se4@Ti3C2Tx) composite as a promising anode material for Li-ion battery (LIB). By using selective experimental conditions, Mo3Se4@ Ti3C2Tx was successfully developed with unique structural and morphological features. When being employed as anode material in LIB, Mo3Se4@Ti3C2Tx delivered high stable reversible specific discharge capacity of 1250 mAh/g at 0.1C, which is significantly higher than traditional carbon-based anode materials. In addition, the composite retained 84.53 % of initial specific capacity when the C-rate was increased from 0.1C to 1.5C, implying excellent rate performance. The Mo3Se4@Ti3C2Tx composite also demonstrated remarkable cycling stability with negligible loss after 378 cycles. This exceptional electrochemical performance can be assigned to the exclusive architecture of Mo3Se4@Ti3C2Tx composite, leading to increase in exposure of active Li+ sites and structural stability.

Electrical bridging effects of dual-carbon microsphere frameworks in Si-based composite anodes for high-performance Li-ion batteries

Herein, the successful fabrication of a high-performance Si-based composite Li-ion battery (LIB) anode, comprising a dual-carbon framework of reduced graphene oxide (r-GO) and oxidized single-walled carbon nanohorns (o-NHs), was demonstrated using a simple and scalable spray-drying process followed by heat treatment (h-s-GO/Si/NH). The r-GO nanosheets in the h-s-GO/Si/NH anode acted as a robust spherical framework that facilitated the mechanical and electrical connection between the carbon-coated Si (c-Si) nanoparticles, homogeneous dispersion of c-Si and o-NH nanoparticles, and suppression of the volume expansion and pulverization that occur during lithiation/delithiation. Additionally, the o-NH nanoparticles incorporated in the h-s-GO/Si/NH composite served as electrical bridges between the r-GO nanosheets, resulting in enhanced electrical conductivity and effortless Li-ion shuttling. The h-s-GO/Si/NH composite anode exhibited high electrochemical performance with a very high initial gravimetric charge capacity (2961 mAh g−1 at 0.1 A g−1), stable initial Coulombic efficiency (80.6% at 0.2 A g−1), and high cycling stability (983 mAh g−1 at 0.2 A g−1 after 50 cycles). This study highlights the importance of the effective design of electrically conductive three-dimensional frameworks in Si-based composite anodes, which may contribute to the development of high-performance LIB anode materials.

Uniform Li-ion diffusion and robust solid electrolyte interface construction for kilogram-scale Si@ZIF powder as the anode in Li-ion batteries

The zeolitic imidazolate framework (ZIF) is characterized by a highly ordered structure, large cavities, and thermal/chemical stabilities and has been widely researched for energy storage. In this study, using commercial Si powder with a diameter of 50–200 nm at a kilogram scale, Si@ZIF core-shell particles with dispersed ZIF-8 rhombic dodecahedrons were fabricated by a one-pot method and achieved excellent electrochemical performance. With the specific pore diameter and ordered network formed by membered rings, experimental results demonstrated that the ZIF-8 shell realized a uniform and accelerated Li+ diffusion route, alleviated volumetric expansion of the Si core, and constructed a LiF-concentrated robust solid electrolyte interface film with less unnecessary consumption of electrolyte and Li+. Density functional theory calculations verified the higher adsorption energy for Li-solvated clusters and the de-solvation effect on the surface of ZIF-8, which can increase Li+ concentration along the one-dimensional channels of 4-membered ring with a diameter similar to that of Li+ for high-speed and uniform Li+ intercalation. Furthermore, the large and elastic rhombic dodecahedrons formed by pure ZIF-8 buffered the volume change and maintained the integrity of the Si electrode during cycling. As a result, the Si@8Z anode achieved a reversible capacity of 818.5 mAh g−1 after 650 cycles at 1 A g−1 with a high initial coulombic efficiency of 88.2 % and outstanding rater performance even at 8 A g−1. Nevertheless, the capacity of the Si anode decreased to 0 mAh g−1 after 200 cycles. The present work clarifies the effect of ZIF on the performance of Si anodes and provides a simple method to modify commercial Si powder.

Retraction Note: High-rate aluminium yolk-shell nanoparticle anode for Li-ion battery with long cycle life and ultrahigh capacity

Retraction Note: High-rate aluminium yolk-shell nanoparticle anode for Li-ion battery with long cycle life and ultrahigh capacity

Engineering a polyaniline nanoneedles-coated multi-layered Co3O4/NiO microsphere as high-performance Li-ion battery anode

High energy-storage Li-ion battery needs a high-capacity anode. However, current graphite-based anode doesn’t meet this requirement, thus developing high performance anode materials is highly needed and significant. Here, we provide a rational engineering of a multi-layered hollow structure combining with surface coating of polyamine (PANI) layer, forming a Co3O4/NiO@PANI hybrid using for Li-ion battery anode. PANI is able to effectively improve the conductivity of active materials; besides, PANI is flexible, which can prevent the collapse of the structure caused by volume-expansion during charge and discharge. The multi-layered morphology improves the utilization ratio of voids inside the conventional hollow structured materials, which is significant to improve capacity in practical applications. The Co3O4/NiO@PANI hybrid-based anode shows a capacity of 1049 mAh g−1 along with a Coulombic efficiency of 99.3% after 100 cycles of 0.2 A g−1. Rate-performance of Co3O4/NiO@PANI exceeds that of the bare Co3O4/NiO. It is believed that the hierarchical structure combining multi-layered hollow morphology with surface coating of conductive polymer presented here would find broad applications for developing high-performance energy-storage hybrids.

Single-step fabrication of fibrous Si/Sn composite nanowire anodes by high-pressure He plasma sputtering for high-capacity Li-ion batteries

To realize high-capacity Si anodes for next-generation Li-ion batteries, Si/Sn nanowires were fabricated in a single-step procedure using He plasma sputtering at a high pressure of 100–500 mTorr without substrate heating. The Si/Sn nanowires consisted of an amorphous Si core and a crystalline Sn shell. Si/Sn composite nanowire films formed a spider-web-like network structure, a rod-like structure, or an aggregated structure of nanowires and nanoparticles depending on the conditions used in the plasma process. Anodes prepared with Si/Sn nanowire films with the spider-web-like network structure and the aggregated structure of nanowires and nanoparticles showed a high Li-storage capacity of 1219 and 977 mAh/g, respectively, for the initial 54 cycles at a C-rate of 0.01, and a capacity of 644 and 580 mAh/g, respectively, after 135 cycles at a C-rate of 0.1. The developed plasma sputtering process enabled us to form a binder-free high-capacity Si/Sn-nanowire anode via a simple single-step procedure.

Design a multiphase interfaced Ge(GeOx)/T-Nb2O5−x/C anode with synergistic high capacity and durability for Li-ion batteries

Germanium-based anodes for lithium-ion batteries have attracted strong focus due to an exceptional storage capacity as high as four times of commercial carbon. Inferior capacity retention, however, caused by large volume changes during cycling impedes their widespread application. Herein, we report a multi-phase Ge(GeOx)/T-Nb2O5−x/C composite synthesized using a simple and scalable high-energy ball milling approach. During ball milling, Nb2O5 substrate would react with Ge to produce amorphous GeOx on the interface of them to realize a unique construction. The Ge(GeOx)/T-Nb2O5−x/C demonstrated far longer durable and reversible capacity for Li storage (960 mAh g−1 at 0.1C and 745 mAh g−1 after 150 cycles at 0.5C, with a capacity retention of up to 86.6%) and much higher initial coulombic efficiency (87.3%) than milled Ge and Ge-T-Nb2O5-C mixture samples. The underlying mechanism is unveiled using thorough experimental characterization and density functional theory calculations. Both clearly and consistently decoupled key factors: the synergistic effects of (i) formation of multiphase structure and (ii) suppression of Ge volume expansion by forming a rigid Li2O from the GeOx on the interface of Ge and T-Nb2O5 over the cycling process. To evaluate the feasibility for practical applications the Ge(GeOx)/T-Nb2O5−x/C without prelithiation is coupled with LiFePO4 or LiCoO2 cathodes for the full-cell test. The initial coulombic efficiency is measured as high as 82.3%. Our study provides a clue to the design of highly reversible capacitive and durable anodes for Li-ion batteries.

Consequences of utilizing a redox-active polymeric binder in Li-ion batteries

Development of new polymeric binders can help enable the use of silicon-rich anodes in Li-ion batteries, by providing stronger adhesion to the active material particles. The compositional features that improve interfacial interactions and mechanical properties can often impart electronic conductivity and redox activity to these polymers, which are generally seen as beneficial to cell performance. Alternatively, it is also possible that the addition of charge-transferring centers to the electrode can accelerate cell degradation. Here, we use an aromatic polyimide (∼320 mA h/g of reversible capacity) to explore how a redox-active conductive polymer can affect cell performance. We demonstrate that the lithiated polymer is less stable than the traditional binders upon storage, leading to increased rates of calendar aging. Furthermore, we determine that the adhesion properties of the polymer deteriorate upon repeated cycling, to an extent that is proportional to the degree of delithiation of the binder. More critically, we establish that progressive degradation of the redox behavior of the polymer leads to the release of “extra” Li+ into the cell, which can give the false perception of good performance even under conditions of poor stability. Our work suggests that redox-active conductive binders can sometimes be detrimental to cell performance, and that works evaluating new polymers must include careful experimental validation under realistic conditions.

Disordered GaSiP solid solution anodes with liquid metal phase for high-performance Li-ion batteries

Silicon (Si) has become the most promising next-generation anode to replace commercial graphite for Li-ion batteries (LIBs) profiting from its large reversible capacity of 4,200 mA h g−1. However, its sluggish reaction kinetics and large volume effect need to be resolved. Herein, we prepare a ternary GaSiP solid solution with a disordered lattice by a facile mechanochemistry method. As anodes of LIBs, the GaSiP provides a reversible capacity of 1,527 mA h g−1 at 100 mA g−1 with an initial Coulombic efficiency (ICE) of 90.8% based on the reversible Li-storage mechanism integrated intercalation and subsequent conversion processes as confirmed by crystallography characterization and electrochemical measurements. Importantly, the GaSiP carbon composite presents a long cycling stability of maintaining 1,362 mA h g−1 after 50 cycles at 0.1 A g−1, and 75% capacity retention rate after 1,200 cycles at 2 A g−1, and a high-rate performance of remaining 440 mA h g−1 at 20 A g−1. Broadly, this work opens the door to develop ternary phosphides with disordered lattice and liquid metallic phase using for electrochemical energy conversion and storage.

Understanding the Electrolyte Chemistry Induced Enhanced Stability of Si Anodes in Li-Ion Batteries based on Physico-Chemical Changes, Impedance, and Stress Evolution during SEI Formation

The volume expansion/contraction of Si-based anodes during electrochemical lithiation/delithiation cycles causes a loss in mechanical integrity and accrued instability of the solid electrolyte interphase (SEI) layer, culminating into capacity fade. Electrolyte additives like fluoroethylene carbonate (FEC) improve SEI stability, but the associated causes still under debate. This work reveals some of the roles of FEC via post-mortem observations/analyses, operando stress measurements and a comprehensive study of the impedance associated with the formation/evolution of SEI during lithiation/delithiation. Usage of 10 vol.% FEC as electrolyte additive leads to significant improvements in cyclic stability, Coulombic efficiency and facilitates smoother/compact/crack-free surface/SEI, in contrast to the cracked/pitted/uneven surface upon non-usage of FEC. Operando stress measurements during SEI formation reveal compressive stress development, followed by loss in mechanical integrity, upon non-usage of electrolyte additive, in contrast to insignificant stress development associated with SEI formation upon usage of FEC. The EIS model proposed here facilitates good fit with the impedance data at all states-of-charges, with the SEI resistance and capacitance exhibiting expected variations with cycling and the SEI resistance progressively decreasing with cycle number in the presence of FEC. By contrast, in the absence of FEC, severe fluctuations observed with the SEI resistance and capacitance indicate instability.

Fe2O3/carbon derived from peanut shell hybrid as an advanced anode for high performance lithium ion batteries

Carbon materials derived from biomass behave sustainability, easy availability, low cost and environmentally benign. And Fe2O3 are considered as promising anodes for high-performance Li-ion batteries (LIBs) because of their rich electrochemical properties, higher theoretical capacity (1007 mAh g−1), non-toxicity, high corrosion resistance and safety. However, the high irreversible capacity loss and poor cycling stability of Fe2O3 hinders its commercial applications in LIBs. In this work, we have developed a Fe2O3@C derived from peanut shell composite by two-step hydrothermal method and low-temperature calcination with the assistance of Fe(NO3)3. As an anode for LIBs, the Fe2O3@C composite an excellent electrochemical performance in term of the specific capacity of 1000.8 mAh g−1 at 200 mA g−1 after 100 cycles, and high rate capability of 573.5 mAh g−1 even at 1 A g−1 after 200 cycles. This enhancement could be attributed to the porous carbon matrix combined with Fe2O3 nanoparticles which could increase contact area between electrolyte and active materials, improve conductivity, and accommodate the volume variations via additional void space during cycling. This work may be provide a new approach to improve anode materials using carbon derived-from biomass with larger reversible capacity and long cycle life in LIBs.