Lithium Storage Behavior Research Articles

Understanding on the Reaction Pathway for Lithium Storage Behavior in Molybdenum Sulfides with Different Sulfur Configuration

Molybdenum disulfide (MoS2) has been considered as promising electrode materials in lithium-ion batteries (LIBs) due to its high theoretical capacity through conversion reactions (MoS2 + 4Li+ + 4e− ↔ Mo + 2Li2S) [1,2]. It is well-known that MoS2 electrode exhibits the intercalation of lithium-ions (167 mAh/g) between layers and the formation of lithium sulfide (669 and 1675 mAh/g) via conversion reaction. Considering these electrochemical reactions, it is speculated that the main capacity in MoS2 electrode originated from lithium sulfide (Li2S) reaction. Thus, research on molybdenum sulfides with higher S (sulfur) content, such as MoSx (2<x<3), MoS3, and MoS4, has been conducted for the development of electrodes with higher capacity [3,4]. Additionally, carbon-based materials are been utilized to overcome the low electrical conductivity and unstable conversion reactions of molybdenum sulfides [5]. However, understanding the precise electrochemical mechanisms of S-rich molybdenum sulfides has challenging due to complex S ligands. Hence, there is a need for a comprehensive understanding of the electrochemical reactions of molybdenum sulfides with various S ligands.In this study, we demonstrate that the electrochemical reaction pathways of molybdenum sulfides are influenced by different S content and configuration. First, we prepared three-molybdenum sulfides (MoS2, MoS3, and [Mo3S13]2-). From the potentiostatic and galvanostatic measurements, the redox reactions of molybdenum sulfides were distinctly observed in terms of S configuration. Depth X-ray photoelectron spectroscopy (XPS) analysis was performed to elucidate the chemical and structural changes in molybdenum sulfides during the transition reactions. Through these analyses, we confirmed that the activation energy of the redox reaction is significantly influenced by the S ligands, indicating that S-rich molybdenum sulfides have the potential to be applied in both anode and cathode roles within lithium storage systems. Furthermore, we addressed the drawbacks of molybdenum sulfides, such as low electrical conductivity and irreversible reactions, by incorporating carbon composites. Utilizing carbon-molybdenum sulfide composites as both anode and cathode materials exhibited capacities of 962 and 406 mAh/g, respectively, at a current density of 0.1 A/g, along with improved rate-capability and stable lifespan. Therefore, we believe that the analysis of lithium storage mechanisms in molybdenum sulfides and the synthesis of carbon composites will greatly contribute to the development of electrode materials for future batteries.

Synergistic effect of molybdenum dioxide wrapped nitrogen doped carbon nanotubes in binder-free anodes for enhanced lithium storage properties

Molybdenum dioxide (MoO2) is regarded as a potential anode for lithium-ion batteries due to its highly theoretical specific capacity. However, its further application in lithium-ion battery is largely limited by insufficient practical discharge capacity and cyclic performance. Here, MoO2nanoparticles are in-situ grown on three-dimensional nitrogen doped carbon nanotubes (NCNTs) on nickel foam substrate homogeneously using a simple electro-deposition method. The unique structural features are favorable for lithium ions insertion and extraction and charge transfer dynamics at electrode/electrolyte interface. As a proof of concept, the as-synthesized nanocomposites have been employed as anode for lithium-ion battery, exhibiting a reversible and significantly improved discharge capacity of ∼517 mA h g-1at the current density of 150 mA g-1as well as superior cycle and rate performance. The first-principle calculations based on density functional theory and electrochemical impedance spectroscopy results demonstrate a reduced energy barrier of lithium ions diffusion, improved lithium storage behavior, reduced structure collapse, and significantly enhanced charge transfer kinetics in MoO2/NCNTs nanocomposites with respect to MoO2powder. The excellent performance makes as-prepared MoO2/NCNTs nanocomposites promising binder-free anode for high performance lithium-ion batteries. This work also provides important theoretical insights for other state-of-the-art batteries design.

Facile synthesis of GexSiO(1-x) alloys as a superior anode enables high-energy lithium-ion batteries

Facile synthesis of GexSiO(1-x) alloys as a superior anode enables high-energy lithium-ion batteries

Sustainable Utilization of Waste Biomass: Pyrolysis Kinetics of Jujube Pits and Lithium Storage Behavior of Pyrolytic Carbon

Sustainable Utilization of Waste Biomass: Pyrolysis Kinetics of Jujube Pits and Lithium Storage Behavior of Pyrolytic Carbon

Ice template-induced assembly coupled with carbonization strategy for preparation of sulfur-doped porous carbon nanosheets from lignite as high-capacity anode for lithium-ion batteries

Ice template-induced assembly coupled with carbonization strategy for preparation of sulfur-doped porous carbon nanosheets from lignite as high-capacity anode for lithium-ion batteries

Lithium storage behaviour of AgNbO3 perovskite: Understanding electrochemical activation and charge storage mechanisms

Lithium storage behaviour of AgNbO3 perovskite: Understanding electrochemical activation and charge storage mechanisms

Enhancing the Lithium Storage Performance of the Nb2O5 Anode via Synergistic Engineering of Phase and Cu Doping.

Nb2O5 has been viewed as a promising anode material for lithium-ion batteries by virtue of its appropriate redox potential and high theoretical capacity. However, it suffers from poor electric conductivity and low ion diffusivity. Herein, we demonstrate the controllable fabrication of Cu-doped Nb2O5 with orthorhombic (T-Nb2O5) and monoclinic (H-Nb2O5) phases through annealing the solvothermally presynthesized Nb2O5 precursor under different temperatures in air, and the Cu doping amount can be readily controlled by the concentration of the precursor solution, whose effect on the lithium storage behaviors of the Cu-doped Nb2O5 is thoroughly investigated. H-Nb2O5 shows obvious redox peaks (Nb5+/Nb4+ and Nb4+/Nb3+) with much higher capacity and better cycling stability than those for the widely investigated T-Nb2O5. When introducing appropriate Cu doping, the optimized H-Cu0.1-Nb2O5 electrode shows greatly enhanced conductivity and lower diffusion barrier as revealed by the theoretical calculations and electrochemical characterizations, delivering a high reversible capacity of 203.6 mAh g-1 and a high capacity retention of 140.8 mAh g-1 after 5000 cycles at 1 A g-1, with a high initial Coulombic efficiency of 91% and a high rate capacity of 144.2 mAh g-1 at 4 A g-1. As a demonstration for full-cell application, the H-Cu0.1-Nb2O5||LiFePO4 cell displays good cycling performance, exhibiting a reversible capacity of 135 mAh g-1 after 200 cycles at 0.2 A g-1. More importantly, this work offers a new synthesis protocol of the monoclinic Nb2O5 phase with high capacity retention and improved reaction kinetics.

Flexible free-standing Fe-CoP-NAs/CC nanoarrays for high-performance full lithium-ion batteries

In this study, a flexible, free-standing Fe-doped CoP nanoarrays electrode for superior lithium-ion storage has been successfully fabricated. The electrode combines the advantages of a Fe-doping and a flexible carbon cloth (CC) support, resulting in a high specific capacity (1356mAh/g at 0.2A/g) and excellent cycling stability (1138mAh/g after 100 cycles). The cyclic voltammetry (CV) curves at different scan rates investigate the outstanding lithium storage behavior of Fe-CoP-NAs/CC which indicates a combined influence of diffusion behavior and capacitance behavior on the electrochemical process. The galvanostatic intermittent titration technique (GITT) analyzes the diffusion kinetics of Li+ which indicates the fast diffusion kinetics in the Fe-CoP/NAs/CC anode. The assembled Fe-CoP-NAs/CC//LiFePO4 battery exhibits a remarkable capacity of 325.2mAh/g even at 5A/g. And the battery also has good cycle stability, and still provides 498.1mAh/g specific capacity after 200 cycles. Moreover, the Fe-CoP-NAs/CC//LiFePO4 soft-pack battery can continuously power the LEDs when it is bent at various angles which demonstrates its potential for use in wearable devices.

Comparison of the lithium storage performance and electrochromic behavior of Prussian blue and its analogues

Comparison of the lithium storage performance and electrochromic behavior of Prussian blue and its analogues

Structure-dependent lithium storage characteristics of Fe3O4/rGO aerogels

Structure-dependent lithium storage characteristics of Fe3O4/rGO aerogels

Molecular-Level Interfacial Chemistry Regulation of MXene Enables Energy Storage beyond Theoretical Limit.

Ti3C2Tx MXene often suffers from poor lithium storage behaviors due to its electrochemically unfavorable OH terminations. Herein, we propose molecular-level interfacial chemistry regulation of Ti3C2Tx MXene with phytic acid (PA) to directly activate its OH terminations. Through constructing hydrogen bonds (H-bonds) between oxygen atoms of PA and OH terminations on Ti3C2Tx surface, interfacial charge distribution of Ti3C2Tx has been effectively regulated, thereby enabling sufficient ion-storage sites and expediting ion transport kinetics for high-performance energy storage. The results show that Li ions preferably bind to H-bond acceptors (oxygen atoms from PA), and the flexibility of H-bonds therefore renders their interactions with adsorbed Li ions chemically "tunable", thus alleviating undesirable localized geometric changes of the OH terminations. Meanwhile the H-bond-induced microscopic dipoles can act as directional Li-ion pumps to expedite ion diffusion kinetics with lower energy barrier. As a result, the as-designed Ti3C2Tx/PA achieves a 2.4-fold capacity enhancement compared with pristine Ti3C2Tx (even beyond theoretical capacity), superior long-term cyclability (220.0 mAh g-1 after 2000 cycles at 2.0 A g-1), and broad temperature adaptability (-20 to 50 °C). This work offers a promising interface engineering strategy to regulate microenvironments of inherent terminations for breaking through the energy storage performance of MXenes.

Necklace‐Structured Silicon Suboxide‐Based Anode Materials with Multiple Carbon Networks for Stable Lithium Storage

AbstractSilicon suboxide (SiOx) attracts great attentions from both academy and industry owing to its higher capacity than graphite and smaller volume swelling than Si, making it possible to achieve a tradeoff between capacity and cycling stability. Whereas, the volume expansion problem and poor electrical conductivity of SiOx severely hinder its practical applications. Herein, a unique necklace‐structured SiOx‐based anode material consisting of carbon nanotube wired SiOx/C@C spheres with a surface carbon coating layer (CNT@SiOx/C@C) is constructed. The multiple carbon networks wire the whole composite anode material, effectively confining the volumetric variation of SiOx, and enhancing the structural integrity of the electrode. The as‐synthesized necklace‐structured CNT@SiOx/C@C manifests decent lithium storage behaviors in terms of discharge capacity (857.7 mAh g−1 at 0.1 A g−1), cyclability (81.7% capacity retention over 100 cycles at 0.1 A g−1), and rate capability (333.3 mAh g−1 at 10 A g−1). This study demonstrates the effectiveness of constructing multiple carbon networks for tackling the volume swelling and conductivity issues of SiOx. It is also anticipated that this structural design would be generally applied to other high‐capacity electrode materials suffering from large volume fluctuation and low conductivity.

Understanding the influence of sulfur configuration on the electrochemical reaction pathway for lithium storage in molybdenum sulfides

Understanding the influence of sulfur configuration on the electrochemical reaction pathway for lithium storage in molybdenum sulfides

Construction of novel lithium-ion battery anode materials with superior rate performance through Fe/Li2O composite interface

Construction of novel lithium-ion battery anode materials with superior rate performance through Fe/Li2O composite interface

The Mechanism of Fluorine Doping for the Enhanced Lithium Storage Behavior in Cation‐Disordered Cathode Oxide

AbstractLi‐rich cation‐disordered rock‐salt (DRX) materials have emerged as promising candidates for high‐capacity oxide cathodes. Their fluorinated variants have shown improved cycling stability with effectively suppressed oxygen loss. However, a comprehensive understanding of how fluorination impacts the multiscale structure and lithium transportation in DRX remains elusive in experiments. Herein, the neutron total scattering technique in conjunction with the advanced reverse Monte Carlo (RMC) fitting method is employed to characterize the intricate structure of Li1.16Ti0.37Ni0.37Nb0.1O2 (LTNNO) and the fluorinated Li1.2Ti0.35Ni0.35Nb0.1O1.8F0.2 (LTNNOF). Through rigorous statistical analysis, the multiscale structural evolution upon fluorination is quantified from atomic (≤5 Å) to long‐range scale (≈100 Å). The local Li‐rich environments around F induce a modest 2.4% increment in the number of fast Li 0TM (transition metal) channels. Crucially, at a broader scale, the proportion of 0TM channels participating in percolation increases significantly from 2.9% in LTNNO to 8.7% in LTNNOF. Fluorination improves the capacity release mainly through merging isolated fast Li channels into the percolation network. This work experimentally unravels the multiscale mechanism of fluorination‐induced performance improvement in DRX materials and highlights the necessity of adopting an advanced RMC fitting method to obtain a full view of the complex structural features in developing high‐capacity DRX cathodes.

Efficient flexible electrodes for lithium-ion batteries utilizing well-dispersed hybrid Mo2C nanoparticles on vertically-oriented graphene nanowalls

Efficient flexible electrodes for lithium-ion batteries utilizing well-dispersed hybrid Mo2C nanoparticles on vertically-oriented graphene nanowalls

ZnMn2O4/ZnMnO3/ZnO composite with novel bilayer heterojunction structure for enhanced lithium storage performance

ZnMn2O4/ZnMnO3/ZnO composite with novel bilayer heterojunction structure for enhanced lithium storage performance

NiM (Sb, Sn)/N-doped hollow carbon tube as high-rate and high-capacity anode for lithium-ion batteries

Alloy-type materials are regarded as prospective anode replacements for lithium-ion batteries (LIBs) owing to their attractive theoretical capacity. However, the drastic volume expansion leads to structural collapse and pulverization, resulting in rapid capacity decay during cycling. Here, a simple and scalable approach to prepare NiM (M: Sb, Sn)/nitrogen-doped hollow carbon tubes (NiMC) via template and substitution reactions is proposed. The nanosized NiM particles are uniformly anchored in the robust hollow N-doped carbon tubes via NiNC coordination bonds, which not only provides a buffer for volume expansion but also avoids agglomerating of the reactive material and ensures the integrity of the conductive network and structural framework during lithiation/delithiation. As a result, NiSbC and NiSnC exhibit high reversible capacities (1259 and 1342 mAh/g after 100 cycles at 0.1 A/g) and fascinating rate performance (627 and 721 mAh/g at 2 A/g), respectively, when employed as anodes of LIBs. The electrochemical kinetic analysis reveals that the dominant lithium storage behavior of NiMC electrodes varies from capacitive contribution to diffusion contribution during the cycling corresponding to the activation of the electrode exposing more NiM sites. Meanwhile, M (Sb, Sn) is gradually transformed into stable NiM during the de-lithium process, making the NiMC structure more stable and reversible in the electrochemical reaction. This work brings a novel thought to construct high-performance alloy-based anode materials.

Rational design of hollow Ti2Nb10O29 nanospheres towards High-Performance pseudocapacitive Lithium-Ion storage

Ti2Nb10O29, as one of the most promising anode materials for lithium-ion batteries (LIBs), possesses excellent structural stability during lithiation/delithiation cycling and higher theoretical capacity. However, Ti2Nb10O29 faces some challenges, such as insufficient ion diffusion coefficient and poor electronic conductivity. To overcome these problems, this study investigates the effect of applying nanostructure engineering on Ti2Nb10O29 and the lithium storage behaviors. We successfully synthesized hollow Ti2Nb10O29 nanospheres (h-TNO NSs) via solvothermal method using phenolic resin nanospheres as the template. The effects of using a template or not and the annealing atmospheres on the microstructures of the as-prepared Ti2Nb10O29 are investigated. Different nanostructures (porous Ti2Nb10O29 nanoaggregates (p-TNO NAs) without a template and core-shelled Ti2Nb10O29@C nanospheres (cs-TNO@C NSs)) were formed through annealing in Ar. When examined as anodes for LIBs, the h-TNO NSs electrode with hollow spherical structure displayed a better lithium storage performance. Compared to its counterparts, p-TNO NAs and cs-TNO@C NSs, h-TNO NSs electrode exhibited a higher reversible capacity of 282.5 mAh g-1 at 1C, capacity retention of 79.5% (i.e., 224.6 mAh g-1) after 200 cycles, and a higher rate capacity of 173.1 mAh g-1 at 10C after 600 cycles. The excellent electrochemical performance of h-TNO NSs is attributed to the novel structure. The hollow nanospheres with cavities and thin shells not only exposed more active sites and improved ion diffusion, but also buffered the volume variation upon cycling and facilitated electrolyte penetration. This consequently enhanced the lithium storage performance of the electrode and its high pseudocapacitive contribution (90% at 1.0mVs-1).

A green recyclable Li3VO4-pectin electrode exhibiting pseudocapacitive effect as an advanced anode for lithium-ion battery

A green recyclable Li3VO4-pectin electrode exhibiting pseudocapacitive effect as an advanced anode for lithium-ion battery