Performance Of Lithium-oxygen Batteries Research Articles

Anion-cation coupled electrolyte additive enhancing the performance of lithium-oxygen batteries

The rational design of electrolyte via introducing additive is an efficient strategy to improve the electrochemical performance of lithium-oxygen batteries (LOBs). In this work, coupling LiCl and Sn(TFSI)2 as the anion-cation electrolyte additive achieved the high-performance of LOBs by promoting the oxygen electrode reactions, regulating the Li+ solvation structure, and inducing the growth of the SEI protective layer. Specifically, Cl− with strong coordination affinity to Li+ could weaken the binding between Li+ and TEGDME solvent molecules, leading to the formation of an anion-dominant Li+ solvation structure, which facilitates the diffusion of Li+ in the electrolyte bulk and electrolyte/electrode interface. On the other hand, Sn2+ can serve as a redox mediator to catalyze ORR on the cathode and participate in the growth of smooth and dense SEI protective layer on Li metal anode surface, thus effectively promoting the oxygen electrode reaction kinetics and suppressing the corrosion of Li anode. As a consequence, the LOBs with coupled LiCl and Sn(TFSI)2 additive exhibited a ultra-high discharge capacity of 21517.1 mA h g−1 and an excellent cycling life of 334 cycles. This work provides a deep understanding for designing efficient electrolyte with additive for LOBs.

Ordered layered manganese‐based metal–organic frameworks induce 2D growth of discharge products via LiO2 adsorbent for high performance lithium–oxygen batteries

Adjusting the morphology and structure of the catalyst to optimize the structure of the discharge product is an effective strategy for improving the electrocatalytic activity of lithium–oxygen batteries (LOBs). In this paper, a novel high‐orientation layered manganese‐based metal–organic frameworks (Mn‐MOFs) catalyst for the air cathode of a LOB is synthesized via a facile solvothermal method using 2,4‐pyridine dicarboxylic acid combined with the metal Mn2+ ion. The presence of layered structure increases the specific surface area of the catalytic material, and the interlayer spacing can be used as a channel for electron and oxygen transport, thus promoting ion diffusion and catalyzing reactions. Otherwise, the coordination of the N element and metal ion in the organic ligand significantly improves the electrical conductivity and oxygen reduction reaction/oxygen extraction reaction (ORR/OER) performance of LOB. The effective combination of Mn2+ and 2,4‐pyridine dicarboxylic acid improves the overall catalytic capacity of the material, leading to a high LiO2 adsorption capacity so as to induce the formation of film discharge products and extend the cycle life of LOBs. When using Mn‐MOFs at 140°C as the cathode catalyst, the specific discharge capacity of the LOB can achieve 5579 mAh/g with a 0.2 mA/cm2 current density and maintain 140 stable cycles, limiting the specific discharge capacity to 500 mAh/g.

Binder-Free Three-Dimensional Porous Graphene Cathodes via Self-Assembly for High-Capacity Lithium-Oxygen Batteries.

The porous architectures of oxygen cathodes are highly desired for high-capacity lithium-oxygen batteries (LOBs) to support cathodic catalysts and provide accommodation for discharge products. However, controllable porosity is still a challenge for laminated cathodes with cathode materials and binders, since polymer binders usually shield the active sites of catalysts and block the pores of cathodes. In addition, polymer binders such as poly(vinylidene fluoride) (PVDF) are not stable under the nucleophilic attack of intermediate product superoxide radicals in the oxygen electrochemical environment. The parasitic reactions and blocking effect of binders deteriorate and then quickly shut down the operation of LOBs. Herein, the present work proposes a binder-free three-dimensional (3D) porous graphene (PG) cathode for LOBs, which is prepared by the self-assembly and the chemical reduction of GO with triblock copolymer soft templates (Pluronic F127). The interconnected mesoporous architecture of resultant 3D PG cathodes achieved an ultrahigh capacity of 10,300 mAh g-1 for LOBs. Further, the cathodic catalysts ruthenium (Ru) and manganese dioxide (MnO2) were, respectively, loaded onto the inner surface of PG cathodes to lower the polarization and enhance the cycling performance of LOBs. This work provides an effective way to fabricate free-standing 3D porous oxygen cathodes for high-performance LOBs.

Zn-assisted low-temperature reconstruction of NiCo heterogeneous catalysts for lithium-oxygen batteries

Developing catalysts with high catalytic activity and durability is an effective strategy for improving the electrochemical performance of lithium-oxygen batteries (LOBs). Metal atom doping and heterostructure construction have shown great potential in catalysis and are expected to be widely used in energy storage. In this study, a Zn-doped NiCo2O4/NiO heterostructured complex catalyst is designed and prepared as a cathode catalyst for LOBs. This metal-doped heterostructured complex catalyst, prepared at a lower annealing temperature, retains the most active sites. Additionally, the three-dimensional hollow structure of the catalyst not only facilitates mass transfer but also provides active sites through doping and heterostructure formation. The Zn-doped NiCo2O4/NiO catalyst exhibits excellent catalytic performance, resulting the generation of a silky Li2O2 discharge product film, and the higher adsorption energy for the intermediate product LiO2 also allows the discharge product to be tightly bound to the catalyst. The improved contact between the discharge products and the catalyst's active sites, along with the increased surface area, enhances charge transport and decomposition properties, leading to good reversibility of the LOB. Consequently, the LOB based on Zn-doped NiCo2O4/NiO heterostructure complex catalyst features high discharge capacity (12160 mAh/g at 200 mA g−1) and excellent durability (353 cycles, ∼1765 h). Furthermore, theoretical calculations show that the Zn-doped complex heterostructures have enhanced reaction kinetics of OER and ORR. This straightforward method of producing metal-doped heterostructured complex catalysts that induce uniform Li2O2 deposition valuable insights for enhancing the performance of LOBs.

Co-deposition of conductive additives and lithium peroxide during discharge to boost the performance of lithium-oxygen batteries

Lithium-oxygen batteries (LOBs) have been regarded as a promising energy storage system for applications in electric vehicles and aviation. However, the development of high-performance LOBs has been hindered by the...

Piperidine-based ionic liquid additive with electrostatic shielding and redox activity enabling advanced lithium-oxygen batteries.

Here, we propose a piperidine-based ionic liquid additive. The electrostatic shielding effect of the piperidine cation (PP13+) effectively inhibits the growth of lithium dendrites. Simultaneously, the redox activity of the bromine anion synergistically reduces the overpotential. This approach significantly improves the cycling performance of lithium-oxygen batteries.

Unsaturated coordination modulation and enlarged pore size in nanoflower-like metal organic frameworks for enhanced lithium-oxygen battery performance

Lithium-oxygen batteries (LOBs) have very high energy density, but reversibility and high capacity are difficult to achieve due to sluggish cathode dynamics. Efficient cathodic catalysts are an effective means to...

Enhancing the Performance of Lithium-Oxygen Batteries with Quasi-Solid Polymer Electrolytes.

The quasi-solid electrolyte membranes (QSEs) are obtained by solidifying the precursor of unsaturated polyester and liquid electrolyte in a glass fiber. By modifying the ratio of tetraethylene glycol dimethyl ether, QSE with balanced ionic conductivity, flexibility, and electrochemical stability window is acquired, which is helpful for inhibiting the decomposition of electrolyte on the cathode surface. The QSE is beneficial to the interfacial reaction of Li+, electrons, and O2 in the quasi-solid lithium-oxygen battery (LOB), can reduce the crossover of oxygen to the anode, and extend the cycle life of LOBs to 317 cycles. Benefitting from the application of QSE, a more stable solid electrolyte interface layer can be constructed on the anode side, which can homogenize Li+ flux and facilitate uniform Li deposition. Lithium-oxygen pouch cell with in situ formed QSE2 works well when the cell is folded or a corner is cut off. Our results indicate that the QSE plays important roles in both the cathode and Li metal anode, which can be further improved with the in situ forming strategy.

ZIF-67 derived 3D nanocage-shaped FeCoNi layered double hydroxides as an electrocatalyst for improving the performance of LOBs

Layered double hydroxides (LDHs) with unique structure features are regarded as ideal materials for energy storage. Developing highly efficient cathode catalysts is crucial for improving the storage capacity and stability of lithium-oxygen batteries (LOBs). Herein, we proposed a facile solvothermal strategy to prepare different metal molar ratios of trimetallic FeCoNi LDHs using the zeolitic imidazolate framework-67 (ZIF-67) as a template. When the metal molar ratios of Fe/Ni = 1.7, the obtained FeCoNi LDH (FCN-C) exhibits a 3D nanocage-shaped structure with highly ordered flower-like nanosheets on the surface. The well-designed structures exhibit high specific surface areas and abundant mic-mesoporous channels, which are favored for the transport of electrons and ions diffusion. The synergistic effects of FeCoNi LDH components can effectively regulate the electronic structure and deliver striking electrochemical activities. Specifically, the LOBs with FCN-C cathode possess an excellent specific capacity of 17598.5 mAh g−1 at 0.05 mA cm−2. Under 0.05 mA cm−2 with a cutoff capacity of 500 mAh g−1, the LOBs assembled by FCN-C cathode can achieve 213 cycles, and it is much longer than that of other FeCoNi LDHs cathodes. This simple preparation method can provide new insight to design efficient electrocatalysts for energy applications.

Poor Cycling Performance of Rechargeable Lithium-Oxygen Batteries under Lean-Electrolyte and High-Areal-Capacity Conditions: Role of Carbon Electrode Decomposition.

There is growing demand for practical implementation of lithium-oxygen batteries (LOBs) due to their superior potential for achieving higher energy density than that of conventional lithium-ion batteries. Although recent studies demonstrate the stable operation of 500Whkg-1 -class LOBs, their cycle life remains fancy. For further improving the cycle performance of LOBs, the complicated chemical degradation mechanism in LOBs must be elucidated. In particular, the quantitative contribution of each cell component to degradation phenomenon in LOBs under lean-electrolyte and high-areal-capacity conditions should be clarified. In the present study, the mass balance of the positive-electrode reaction in a LOB under lean-electrolyte and high-areal-capacity conditions is quantitatively evaluated. The results reveal carbon electrode decomposition to be the critical factor that prevents the prolonged cycling of the LOB. Notably, the carbon electrode decomposition occur during charging at voltages higher than 3.8V through the electrochemical decomposition of solid-state side products. The findings of this study highlight the significance of improving the stability of the carbon electrode and/or forming Li2 O2 , which can decompose at voltages lower than 3.8V, to realize high-energy-density LOBs with long cycle life.

Chromium-doped inverse spinel electrocatalysts with optimal orbital occupancy for facilitating reaction kinetics of lithium-oxygen batteries

Tailored electrocatalysts that can modulate their electronic structure are highly desirable to facilitate the reaction kinetics of oxygen evolution reaction (OER) and oxidation reduction reaction (ORR) in lithium-oxygen batteries (LOB). Although octahedron predominant inverse spinels (e.g., CoFe2O4) have been proposed as promising candidates for catalytic reactions, their performance has remained unsatisfactory. Herein, the chromium (Cr) doped CoFe2O4 nanoflowers (Cr-CoFe2O4) are elaborately constructed on nickel foam as a bifunctional electrocatalyst that drastically improves the performance of LOB. The results show that the partially oxidized Cr6+ stabilizes the cobalt (Co) sites at high-valence and regulates the electronic structure of Co sites, facilitating the oxygen redox kinetics of LOB due to their strong electron-withdrawing capability. Moreover, DFT calculations and ultraviolet photoelectron spectrometer (UPS) results consistently demonstrate that Cr doping optimizes the eg electron filling state of the active octahedral Co sites, significantly improves the covalency of Co-O bonds, and enhances the degree of Co 3d-O 2p hybrids. As a result, Cr-CoFe2O4 catalyzed LOB can achieve low overpotential (0.48 V), high discharge capacity (22030 mA h g−1) and long-term cycling durability (over 500 cycles at 300 mA g−1). This work promotes the oxygen redox reaction and accelerates the electron transfer between Co ions and oxygen-containing intermediates, highlighting the potential of Cr-CoFe2O4 nanoflowers as bifunctional electrocatalysts for LOB.

Engineering the Electronic Interaction between Atomically Dispersed Fe and RuO2 Attaining High Catalytic Activity and Durability Catalyst for Li-O2 Battery.

It is significant to develop catalysts with high catalytic activity and durability to improve the electrochemical performances of lithium-oxygen batteries (LOBs). While electronic metal-support interaction (EMSI) between metal atoms and support has shown great potential in catalytic field. Hence, to effectively improve the electrochemical performance of LOBs, atomically dispersed Fe modified RuO2 nanoparticles are designed to be loaded on hierarchical porous carbon shells (FeSA -RuO2 /HPCS) based on EMSI criterion. It is revealed that the Ru-O-Fe1 structure is formed between the atomically dispersed Fe atoms and the surrounding Ru sites through electron interaction, and this structure could act as the ultra-high activity driving force center of oxygen reduction/evolution reaction (ORR/OER). Specifically, the Ru-O-Fe1 structure enhances the reaction kinetics of ORR to a certain extent, and optimizes the morphology of discharge products by reducing the adsorption energy of catalyst for O2 and LiO2 ; while during the OER process, the Ru-O-Fe1 structure not only greatly enhances the reaction kinetics of OER, but also catalyzes the efficient decomposition of the discharge products Li2 O2 by the favorable electron transfer between the active sites and the discharge products. Hence, LOBs based on FeSA-RuO2 /HPCS cathodes show an ultra-low over-potential, high discharge capacity and superior durability.

2H-MoS 2 Modified Nitrogen-Doped Hollow Mesoporous Carbon Spheres as the Efficient Catalytic Cathode Catalyst for Aprotic Lithium-Oxygen Batteries

2H-MoS ₂ Modified Nitrogen-Doped Hollow Mesoporous Carbon Spheres as the Efficient Catalytic Cathode Catalyst for Aprotic Lithium-Oxygen Batteries

Tailoring the growth route of lithium peroxide through the rational design of a sodium-doped nickel phosphate catalyst for lithium-oxygen batteries.

Tailoring the morphology and structure of Li2O2, the discharge product of lithium-oxygen batteries (LOBs), through the rational design of cathode catalysts is an efficient strategy to promote the electrochemical performance of LOBs. In this work, sodium-doped nickel phosphate nanorods (Na-NiPO NRs) grown on Ni foam (NF) were prepared by the hydrothermal method and subsequent calcination. For the Na-NiPO NRs, the electronic structure could be optimized and abundant void space among the nanorods would provide abundant transport channels. Adopted as the cathodes, the Na-NiPO NRs could facilitate the uniform growth of sea cucumber-like Li2O2 with sufficient Li2O2-electrolyte and Li2O2-catalyst interfaces, significantly promoting the charge process. Therefore, LOBs could deliver a high discharge capacity of 10365.0 mA h g-1 at 100 mA g-1. And a low potential gap of 1.16 V can be achieved at 200 mA g-1 with a capacity of 500 mA h g-1. The proposed strategy demonstrates the role of the morphology and electronic structure of the cathode catalysts in tuning the Li2O2 morphology and provides a novel approach for achieving high-performance LOBs.

Band engineering in heterostructure catalysts to achieve High-Performance Lithium-Oxygen batteries

The electronic structure of cathode catalysts dominates the electrochemistry reaction kinetics in lithium-oxygen batteries. However, conventional catalysts perform inferior intrinsic activity due to the low d-band level of the active sites makes it difficult to bond with the reaction intermediates, which results in poor electrochemical performance of lithium-oxygen batteries. Herein, NiFe2O4/MoS2 heterostructures are elaborately constructed to reach an electronic state balance for the active sites, which realizes the upper shift of the d-band level and enhanced adsorption of intermediates. Density functional theory calculation suggests that the d-band center of Fe active sites on the heterostructure moves toward the Fermi level, demonstrating the heterointerface engineering endows Fe active sites with high d-band level by the transfer and balance of electron. As a proof of concept, lithium-oxygen battery catalyzed by NiFe2O4/MoS2 exhibits a large specific capacity of 21526 mA h g−1 and an extended cycle performance for 268 cycles. Moreover, NiFe2O4/MoS2 with strong adsorption to intermediates promotes the uniform growth of discharge products, which is favor of the reversible decomposition during cycling. This work presents the energy band regulation of the active sites in heterostructure catalysts has great feasibility for enhancing catalytic activities.

Dual functional mesoporous silica colloidal electrolyte for lithium-oxygen batteries

Dual functional mesoporous silica (mSiO2) colloidal electrolytes are promising to protect lithium anode and accelerate the reaction kinetics on cathode for lithium-oxygen batteries (LOBs).In this work, we achieved a significantly extended battery life (from 55 to 328 cycles) of LOB by using mSiO2 with a concentration of 80 mg L−1 in the colloidal electrolyte, compared with the one using conventional LiClO4/DMSO electrolyte. The rate performance and full-discharge capacity are also dramatically enhanced. The as-synthesized mSiO2 has a special ordered hexagonal mesoporous structure, with a high specific surface area of 1016.30 m2/g, which can form a stable colloid after mixing with 1.0 M LiClO4/DMSO. The side reactions of Li stripping/plating are suppressed, thus the cycling life performance of LOB is enhanced by relieving the attack of superoxide intermediates. The co-deposition of mesoporous mSiO2 and Li2O2 also effectively accelerated the decomposition of the discharge product by promoting the mass transfer at the cathode. This investigation of suppressing side reactions using non-aqueous electrolytes will shed a new light on the design and development of novel lithium metal batteries.

Pulsed Current Boosts the Stability of the Lithium Metal Anode and the Improvement of Lithium-Oxygen Battery Performance.

Lithium-oxygen batteries have received extensive attention due to their high theoretical specific capacity, but problems such as high charging overpotential and poor cycling performance hinder their practical application. Herein, a pulsed current, which merits its relaxation phenomenon, is applied during the charging cycle to address the abovementioned problems. Pulsed charging can not only reduce the charging overpotential, but also control the mass transfer and distribution of lithium ions. As a result, the uniform deposition of lithium ions on the anode surface is realized, the repeated rupture and formation of the solid electrolyte interphase is reduced, and the growth of the lithium dendrites is successfully suppressed, thereby achieving the purpose of protecting lithium metal from excessive consumption. When the pulsed charging duty ratio (Ton/Toff) is 1:1, after 25 cycles, the lithium-oxygen battery anode still presents a relatively flat and dense deposition surface, which is obviously better than the loose and rough surface after normal cycling. In addition, the protective effect of pulsed charging on the lithium metal anodes of lithium-oxygen batteries is also verified by the construction of other lithium-based batteries.

The Impact of Multi-Layered Porosity Distribution on the Performance of Lithium-Oxygen Batteries with Organic Electrolyte

Li-oxygen batteries have attracted much attention in the last few years because of their relatively high theoretical energy densities compared to other batteries and because of the recent advancements in material technologies. The high theoretical energy density of Li-oxygen batteries makes these batteries suitable for applications requiring light power sources such as portable electronic devices, unmanned aerial vehicles, and renewable energy storage. In this presentation, we investigate the impact of the porosity distribution on the performance of Li-air batteries with cathodes made of carbon nanotube foams. After presenting the transport model appropriate for such cathodes, we develop a mathematical optimization method to find the optimum 1-D porosity distribution inside the Li-air battery that maximizes the energy density of these batteries. Our preliminary results show that to maximize the energy density of Li-air batteries, it is better to use cathodes with spatially variable porosity, in which the porosity at the oxygen entrance is higher than near the separator. More details about the mathematical approach and preliminary experimental data will be presented at the conference.

Phosphorus Vacancies and Heterojunction Interface as Effective Lithium‐Peroxide Promoter for Long‐Cycle Life Lithium–Oxygen Batteries

AbstractAn electrocatalyst with excellent performance is widely perceived as core materials to solve the practical application of lithium–oxygen batteries (LOBs). Vacancy/interfacial engineering can affect reaction intermediate adsorption and catalytic activity by manipulating the local electronic structure, which is key to improving the performance of LOBs. Here, MoO2‐supported Mo3P@Mo nanocomposites with phosphorus vacancy and interfacial contact are facile synthesized and used as the electrocatalyst to control the morphology of lithium peroxide (Li2O2) and to boost the electrochemical performance of LOBs. The nanocomposites exhibit excellent electrochemical performance with lower overpotential and super long cycling stability, can stably cycle for 500 cycles at 500 mA g−1 with a round‐trip efficiency close to 100%, and can work for 1370 h with failure at the lower cut‐off of 2 V. The influence of the interface and phosphorus vacancy, and the catalytic mechanism are explained by the result about first‐principles calculations and experimental studies.

Ultrasonic-assisted enhancement of lithium-oxygen battery

Lithium-oxygen batteries have attracted much attention due to their high theoretical specific capacity, but their high overpotential and poor cyclic stability limit further development. These are usually closely related to the reversible reactions of the formation and decomposition of the discharge product Li2O2. This study presents the feasibility of ultrasonic-assisted enhancement of lithium-oxygen battery performance. Under the application of ultrasonic charging with 5:5 duty cycle and 675 W power, the rapid upward trend of charging voltage can be effectively suppressed, and the original overpotential of the lithium-oxygen battery can be reduced by 25.9%. In addition, at a limited specific capacity of 400 mAh g−1 and a current density of 800 mA g−1, when applying ultrasonic charging process with above ultrasonic condition every 20 cycles, the cycle life of lithium-oxygen battery with Co3O4 as the positive electrode can reach 321 cycles. Ultrasonic charging has positive effects on suppressing concentration polarization, enhancing mass transfer, and improving oxygen evolution reaction kinetics. It can effectively promote the rapid decomposition of the discharge product Li2O2, reduce the overpotential, and improve the battery cycle performance and stability.