Enhancement Of Cycling Stability Research Articles

By Introducing Multiple Hydrogen Bonds Endows MOF Electrodes with an Enhanced Structural Stability.

Recently, metal-organic frameworks (MOFs) have attracted great interest in energy storage areas. However, the poor structural stability of MOFs derived from weak coordination bonds limits their applications. Here, quadruple hydrogen bonds (H-bonds) were introduced onto the MOFs to enhance their structural stability. Cross-linked networks could be formed between molecules owing to multiple H-bonds, strengthening the framework stability. Moreover, the dynamic reversibility of H-bonds could endow MOFs with self-healing ability. Furthermore, due to lower binding energy compared to coordination bonds, H-bonds break preferentially when subjected to internal stress, thus protecting the MOFs. Consequently, the as-prepared self-healing hybrid (SHH-Cu-MOF@Ti3C2TX) exhibited high capacitance retention (89.4%) after 5000 cycles at 1 A g-1, while that hybrid without dynamic H-bonds (H-Cu-MOF@Ti3C2TX) presented a 79.9% retention, delivering an enhancement in cycling stability. Moreover, an asymmetric supercapacitor (ASC) was fabricated by employing SHH-Cu-MOF@Ti3C2TX and activated carbon (AC) as the electrodes. The ASC delivered a specific capacitance (47.4 F g-1 at 1 A g-1), an energy density (16.9 Wh kg-1), and a power density (800 W kg-1) as well as good rate ability (retains 81% of its initial capacitance from 0.2 A g-1 to 5 A g-1).

Enhancing P2/O3 Biphasic Cathode Performance for Sodium-Ion Batteries: A Metaheuristic Approach to Multi-Element Doping Design.

Sodium-ion batteries (SIBs) have emerged as a compelling alternative to lithium-ion batteries (LIBs), exhibiting comparable electrochemical performance while capitalizing on the abundant availability of sodium resources. In SIBs, P2/O3 biphasic cathodes, despite their high energy, require furthur improvements in stability to meet current energy demands. This study introduces a systematic methodology that leverages the meta-heuristically assisted NSGA-II algorithm to optimize multi-element doping in electrode materials, aiming to transcend conventional trial-and-error methods and enhance cathode capacity by the synergistic integration of P2 and O3 phases. A comprehensive phase analysis of the meta-heuristically designed cathode material Na0.76Ni0.20Mn0.42Fe0.30Mg0.04Ti0.015Zr0.025O2 (D-NFMO) is presented, showcasing its remarkable initial reversible capacity of 175.5mAh g-1 and exceptional long-term cyclic stability in sodium cells. The investigation of structural composition and the stabilizing mechanisms is performed through the integration of multiple characterization techniques.Remarkably, the irreversible phase transition of P2→OP4 in D-NFMO is observed to be dramatically suppressed, leading to a substantial enhancement in cycling stability. The comparison with the pristine cathode (P-NFMO) offers profound insights into the long-term electrochemical stability of D-NFMO, highlighting its potential as a high-voltage cathode material utilizing abundant earth elements in SIBs. This study opens up new possibilities for future advancements in sodium-ion battery technology.

Surface encapsulation of layered oxide cathode material with NiTiO3 for enhanced cycling stability of Na-ion batteries

Abstract In Na-ion batteries, O3-type layered oxide cathode materials encounter challenges such as particle cracking, oxygen loss, electrolyte side reactions, and multi-phase transitions during the charge/discharge process. This study focuses on surface coating with NiTiO3 achieved via secondary heat treatment using a coating precursor and the surface material. Through in-situ x-ray diffraction (XRD) and differential electrochemical mass spectrometry (DEMS), along with crystal structure characterizations of post-cycling materials, it was determined that the NiTiO3 coating layer facilitates the formation of a stable lattice structure, effectively inhibiting lattice oxygen loss and reducing side reaction with the electrolyte. This enhancement in cycling stability was evidenced by a capacity retention of approximately 74% over 300 cycles at 1 C, marking a significant 30% improvement over the initial sample. Furthermore, notable advancements in rate performance were observed. Experimental results indicate that a stable and robust surface structure substantially enhances the overall stability of the bulk phase, presenting a novel approach for designing layered oxide cathodes with higher energy density.

Significant Strain Dissipation via Stiff-Tough Solid Electrolyte Interphase Design for Highly Stable Alloying Anodes.

The pulverization of alloying anodes significantly restricts their use in lithium-ion batteries (LIBs). This study presents a dual-phase solid electrolyte interphase (SEI) design that incorporates finely dispersed Al nanoparticles within the LiPON matrix. This distinctive dual-phase structure imparts high stiffness and toughness to the integrated SEI film. In comparison to single-phase LiPON film, the optimized Al/LiPON dual-phase SEI film demonstrates a remarkable increase in fracture toughness by 317.8%, while maintaining stiffness, achieved through the substantial dissipation of strain energy. Application of the dual-phase SEI film on an Al anode leads to a 450% enhancement in cycling stability for lithium storage in dual-ion batteries. A similar enhancement in cycling stability for silicon anodes, which face severe volume expansion issues, is also observed, demonstrating the broad applicability of the dual-phase SEI design. Specifically, homogeneous Li-Al alloying has been observed in conventional LIBs, even when paired with a high mass loading LiNi0.5Co0.3Mn0.2O2 cathode (7 mg cm-2). The dual-phase SEI film design can also accelerate the diffusion kinetics of Li-ions through interface electronic structure regulation. This dual-phase design can integrate stiffness and toughness into a single SEI film, providing a pathway to enhance both the structural stability and rate capability of alloying anodes.

Significant Strain Dissipation via Stiff‐Tough Solid Electrolyte Interphase Design for Highly Stable Alloying Anodes

AbstractThe pulverization of alloying anodes significantly restricts their use in lithium‐ion batteries (LIBs). This study presents a dual‐phase solid electrolyte interphase (SEI) design that incorporates finely dispersed Al nanoparticles within the LiPON matrix. This distinctive dual‐phase structure imparts high stiffness and toughness to the integrated SEI film. In comparison to single‐phase LiPON film, the optimized Al/LiPON dual‐phase SEI film demonstrates a remarkable increase in fracture toughness by 317.8 %, while maintaining stiffness, achieved through the substantial dissipation of strain energy. Application of the dual‐phase SEI film on an Al anode leads to a 450 % enhancement in cycling stability for lithium storage in dual‐ion batteries. A similar enhancement in cycling stability for silicon anodes, which face severe volume expansion issues, is also observed, demonstrating the broad applicability of the dual‐phase SEI design. Specifically, homogeneous Li−Al alloying has been observed in conventional LIBs, even when paired with a high mass loading LiNi0.5Co0.3Mn0.2O2 cathode (7 mg cm−2). The dual‐phase SEI film design can also accelerate the diffusion kinetics of Li‐ions through interface electronic structure regulation. This dual‐phase design can integrate stiffness and toughness into a single SEI film, providing a pathway to enhance both the structural stability and rate capability of alloying anodes.

A modified reduced graphite oxide anode for sodium ion storage in ether‐based electrolyte

In this work, reduced graphite oxide (rGO) with a long-range-ordered layered structure and an expanded interlayer spacing is synthesized and utilized as an anode for sodium ion storage. Unlike Na+-solvent co-intercalation in flake graphite, the interaction between Na-ions and graphene layers of the rGO shows a capacitive behavior. All the surface defects, pores, and functional groups generated on the surface of rGO can contribute to additional capacity of sodium storage. Thereby, a reversible capacity of 145.7 mAh g−1 at 1 A g−1 and a rate performance of 131.7 mAh g−1 at 1.8 A g−1 could be obtained. Capacity retention of 87.7 % after 900 cycles at 400 mA g−1 was also achieved. Further enhancement in cycling stability, with little capacity decay after 1500 cycles, was obtained after incorporating Ag onto the surface of the rGO. The rGO-Ag anode delivered higher energy density and power density as compared to rGO at the same current density. Even at a power density of 5493 W kg−1 (3A g−1, 24 C), the energy density was as high as 236.2 Wh kg−1. These results contribute to the development of a low-cost, high-performance sodium ion storage devices.

NiCoP@CoS tree-like core-shell nanoarrays on nickel foam as battery-type electrodes for supercapacitors

• NiCoP@CoS tree-like core-shell nanoarrays for supercapacitors. • The 3D hierarchical architecture integrates 1D NiCoP as core and 2D CoS as shell. • Superior battery-type electrochemical supercapacitor performance is achieved. High-performance supercapacitors as the promising energy storage devices have attracted considerable research interests, due to the apparent merits of high power density, fast charge/discharge, and long lifetime. However, their further practical applications are still greatly hindered by the limited energy density, as well as low capacitance, inferior rate capability and poor cycling performance of the electrode materials. Herein, three-dimensional (3D) hierarchical NiCoP@CoS tree-like core-shell nanoarrays (NAs) on nickel foam (NF) are obtained with the vertically grown NiCoP nanowires as core via phosphorization of NiCo 2 O 4 nanowires arrays, and the subsequently electrodeposited CoS nanosheets as shell. The 3D hierarchical tree-like core-shell nanoarrays take advantages of one-dimensional (1D) core as “hyperchannel” for electron transfer, coupling with two-dimensional (2D) vertical shell for fast ion diffusion meanwhile enhancement of cycling stability. The proposed NiCoP@CoS NAs/NF electrode exhibits superior battery-type electrochemical supercapacitor performance via the synergy of NiCoP nanowires and CoS nanosheets, which delivers a high specific capacitance of 1796 F g −1 at 2 A g −1 , outstanding rate capability and good cycling stability with high capacitance retention of 91.4% after 5000 cycles even at 10 A g −1 . Furthermore, the asymmetric supercapacitor assembled by NiCoP@CoS NAs/NF and activated carbon achieves a high energy density (35.8 Wh kg −1 ) at a power density of 748.9 W kg −1 . The as-fabricated NiCoP@CoS tree-like core-shell nanoarrays hold great promise as novel battery-type electrodes for high-performance supercapacitor applications.

Enhancement of cycling stability and capacity of lithium secondary battery by engineering highly porous AlV3O9

Nowadays, the development of nanostructures of oxide-based materials gained significant research interest owing to their new merits and avenues to design better electrodes for lithium-ion battery. It is well known that vanadium and vanadium-based oxide materials have high theoretical capacity but the practical applications are limited mainly due to the fast capacity fading, resulting from the structural collapse, upon cycling and poor electronic conductivity. In this paper, we demonstrate the fabrication of mesoporous vanadium-based oxide with nanostructures, which significantly improved the capacity fading upon cycling. A simple and generic synthetic protocol has been proposed to synthesize highly porous AlV3O9 using aluminum nitrate and ammonium vanadate with the assistance of sucrose. It is found that the decomposition of surface-adsorbed sucrose during the course of AlV3O9 preparation creates homogeneously distributed mesopores. The prepared porous AlV3O9 has been used to fabricate positive electrode for lithium rechargeable battery where high discharge capacity of 240 mAhg−1 was achieved at 0.2 C rate, which is comparable to the best reported results of vanadium-based positive electrodes. The characteristic features are 240 mAhg−1 capacity and ~ 100% columbic efficiency, demonstrating porous AlV3O9 as a promising cathode material for high-power batteries.

Graphene-like MoS2 Nanosheets on Carbon Fabrics as High-Performance Binder-free Electrodes for Supercapacitors and Li-Ion Batteries.

Two-dimensional layer-structure materials are now of great interest in energy storage devices, owing to their graphene-like structure and high theoretical capacity. Herein, graphene-like molybdenum disulfide (MoS2) nanosheets were uniformly grown on carbon fabrics by using a hydrothermal method. They were evaluated as binder-free electrodes for Li-ion batteries (LIBs) and supercapacitors. As expected, long cycling life and high capacity/capacitance are achieved. When used as self-standing electrodes for LIBs, they deliver a high area capacity of ∼0.5 mAh/cm2 even after 400 cycles and remarkable rate capability in the charge/discharge potential range of 1–3 V. In addition, a three-dimensional integrated electrode of the MoS2 nanosheet exhibits a high capacitance of 103.5 mF/cm2 and long cycling stability up to at least 15 000 cycles at a current density of 3 mA/cm2 for supercapacitors. The great cycling stability of MoS2 in supercapacitors is promising in the enhancement of cycling stability through their integration with other materials as alternatives to graphene in some special fields.

Enhancement in cycling stability of LiNi0.5Mn1.5O4/Li cell under high temperature in gel polymer electrolyte system by Tris(trimethylsilyl) borate additive

Tris(trimethylsilyl) borate (TMSB) has been taken as solid electrolyte interface forming additive in carbonated liquid electrolyte of current lithium ion battery, but it has not been applied in Gel Polymer Electrolyte (GPE) yet. In this investigation, TMSB is selected to enhance the cyclic performance of high voltage cathode LiNi0.5Mn1.5O4 under elevated temperature in traditional poly(vinylidene fluoride-co-hexafluoropropylene) (P(VdF-HFP)) based GPE system. By addition of 1 wt% TMSB into GPE, 79% capacity retention ratio is kept at room temperature after 1000 cycles for Li/LiNi0.5Mn1.5O4 coin cell, whose retention value is almost the same as the GPE without additive. However, the discharge capacity retention is improved to 86% after 230 cycles with TMSB additive at high temperature of 55 °C, compared with 75% retention for the GPE without additive. From the physical and chemical characterization, it finds that the improvement in electrochemical performance of GPE with additive is caused by the formation of thin and uniform solid electrolyte interface layer between the GPE and cathode material, which is beneficial to inhibit the further decomposition of liquid component in GPE system and keep the structure integrity of LiNi0.5Mn1.5O4 cathode under high temperature environment.

Wrapping mesoporous Fe2O3 nanoparticles by reduced graphene oxide: Enhancement of cycling stability and capacity of lithium ion batteries by mesoscopic engineering

The fast capacity fading at high current density turns out to be one of the key challenges limiting the broad applications of transition metal oxide-based electrodes. Herein, Fe2O3 nanoparticles with well-defined mesopores wrapped by reduced graphene oxide (RGO) have been synthesized via a facile hydrothermal strategy. The as-prepared nanocomposites were systematically characterized. XPS and Raman analyses confirm the co-existence of Fe2O3 and RGO in the nanocomposite system. SEM and TEM reveal that the mesoporous Fe2O3 nanoparticles have a size of 20–60 nm and are uniformly dispersed and tightly wrapped by RGO. When used as the anode in lithium ion batteries, the mesoporous-Fe2O3/RGO electrode exhibits excellent cycling stability (1098 mA h g−1 after 500 cycles at 1 A g−1) and superior rate capability (574 mA h g−1 at 5 A g−1). The excellent electrochemical performance can be mainly ascribed to the unique mesoscopic architecture that serves as a cushion to alleviate volume change of Fe2O3 during discharge/charge cycles, provides a sustainably large contact area with the electrolyte, and improves electrical conductivity. This unique nanocomposite electrode holds great potential as an anode material for advanced lithium ion batteries.

Enhancement of Cycle Stability and Durability in Secondary Zinc-Air Batteries By Optional Ion-Transporting Separator

Highly durable secondary zinc air batteries were developed using polypropylene (PP) membrane (Celguard 5550) coated with polymerized ionic liquid as separators. The anionic exchange polymer was synthesized copolymerizing 1-[(4-ethenylphenyl)methyl]-3-butyl-imidazolium hydroxide (EBIH) and butyl methacrylate (BMA) monomers by free radical polymerization for both functionality and structural integrity. The ionic liquid induced copolymer was coated on a commercially available PP membrane. The coat allows anionic transfer through the separator and minimizes the migration of zincate ions, which causes the loss of active sites by the formation of zinc oxide on the surface of the catalyst layer. Electrochemical Impedance Spectroscopy (EIS) during the cycle process elucidated the premature failure of cells due to the zinc cross over for the untreated cell and revealed a substantial importance must be placed in zincate control. Scanning electron microscopy (SEM) revealed significant decrease in the porosity of the coated film without large cell performance sacrifice. Energy dispersive x-ray spectroscopy (EDS) data revealed the copolymer coated separator showed less zinc element in the cathode electrolyte, indicating lower zinc permeation through the membrane. Ion Coupled Plasma Optical Emission Spectroscopy (ICP-OES) analysis confirmed over 96% of zinc ion cross over was reduced. In our charge/discharge setup, the constructed cell with the ionic liquid induced copolymer casted separator exhibited drastically improved durability as the battery life increased more than 281% compared to the pure commercial PP membrane.

Tailoring Surface Acidity of Metal Oxide for Better Polysulfide Entrapment in Li‐S Batteries

The polysulfide shuttle reaction has severely limited practical applications of Li‐S batteries. Recently, functional materials that can chemically adsorb polysulfide show significant enhancement in cycling stability and Coulombic efficiency. However, the mechanism of the chemisorption and the control factors governing the chemisorption are still not fully understood. Here, it is demonstrated for the first time that the surface acidity of the host material plays a crucial role in the chemisorption of polysulfide. By tailoring the surface acidity of TiO2 via heteroatom doping, the polysulfide‐TiO2 interaction can be fortified and thus significantly the capacity fading be reduced to 0.04% per cycle. The discovery presented here sheds light on the mechanism of this interfacial phenomenon, and opens a new avenue that can lead to a practical sulfur/host composite cathode.

3D Carbonaceous Current Collectors: The Origin of Enhanced Cycling Stability for High‐Sulfur‐Loading Lithium–Sulfur Batteries

The cycling stability of high‐sulfur‐loading lithium–sulfur (Li–S) batteries remains a great challenge owing to the exaggerated shuttle problem and interface instability. Despite enormous efforts on design of advanced electrodes and electrolytes, the stability issue raised from current collectors has been rarely concerned. This study demonstrates that rationally designing a 3D carbonaceous macroporous current collector is an efficient and effective “two‐in‐one” strategy to improve the cycling stability of high‐sulfur‐loading Li–S batteries, which is highly versatile to enable various composite cathodes with sulfur loading >3.7 mAh cm−2. The best cycling performance can be achieved upon 950 cycles with a very low decay rate of 0.029%. Moreover, the origin of such a huge enhancement in cycling stability is ascribed to (1) the inhibition of electrochemical corrosion, which severely occurs on the typical Al foil and disables its long‐term sustainability for charge transfer, and (2) the passivation of cathode surface. The role of the chemical resistivity against corrosion and favorable macroscopic porous structure is highlighted for exploiting novel current collectors toward exceptional cycling stability of high‐sulfur‐loading Li–S batteries.

Facile synthesis of Mo–Ni particles and their effect on the electrochemical kinetic properties of La–Mg–Ni-based alloy electrodes

A simple method was developed to synthesize Mo–Ni compounds using a chemical reduction method. The compound was then added to La–Mg–Ni-based alloy electrodes in order to improve the electrochemical kinetics of the electrodes. Scanning electron microscopy and transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy showed that the as-synthesized compound consisted of nanoparticles with a chemical composition of MoNi2.5. X-ray diffraction analysis revealed that the compound mainly consisted of a MoNi3 and a Ni phase. The Mo–Ni particles were added to the La–Mg–Ni-based alloy electrode material and uniformly distributed on the alloy surface. An improvement in initial discharge capacity and high rate dischargeability (HRD) could be observed, as well as an enhancement of cycle stability. At 1500mA/g the HRD increased by 10.2%, and the initial discharge capacity increased from 286mAh/g to 307mAh/g. After adding the particles to the alloy, the Mo–Ni particles showed a high electro-catalytic activity due to a charge transfer reaction on the alloy surface, thereby decreasing the charge transfer resistance and increasing the exchange current density. Consequently, the kinetics of the electrode reaction was significantly improved due to an enhancement of the electro-catalytic activity.

Enhanced cycling performance of spinel LiMn2O4 coated with ZnMn2O4 shell

ZnMn2O4 shell-coated LiMn2O4 was prepared by a simple routine that the mixture of LiMn2O4 and ZnO were heated at 750 °C. The structure and electrochemical performance of as-prepared powder compared with the pure LiMn2O4 were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDAX), and galvanostatic charge–discharge testing, respectively. The results of XRD, SEM, and EDAX show that ZnMn2O4 is formed on the surface of LiMn2O4 particles. Charge–discharge testing reveals that ZnMn2O4 shell-coated LiMn2O4 greatly enhances the capacity retention of the spinel LiMn2O4. Furthermore, the modified LiMn2O4 shows significant enhancement in cycling stability at rates from 0.5 C to 12 C. It is found that the improved cycling performance and rate capability of the modified LiMn2O4 are attributed to the effective decrease of manganese dissolution from spinel structure because of ZnMn2O4 shell coated on the surface of LiMn2O4 particle.

Enhanced High-Rate Cycling Stability of LiMn2O4 Cathode by ZrO2 Coating for Li-Ion Battery

The effect of a sol-gel derived amorphous zirconium oxide surface coating on the high charge-discharge (CD) rate performance of was studied. When cycled between 4.5 and (vs. ) at room temperature, the coated spinel electrode, containing , shows tremendous enhancement in cycling stability at CD rates up to . Concurrently, the coated spinel electrode exhibits a lower cubic-tetragonal transition potential, a smaller charge-transfer impedance by 4-5-fold, and it profoundly reduces, by 66%, lattice contraction upon charge (delithiation). The enhancement in the high-rate cycling stability has been attributed to the combination of these favorable effects.