Given that the performance of a lithium–oxygen battery (LOB) is determined by the electrochemical reactions occurring on the cathode, the development of advanced cathode nanoarchitectures is of great ...importance for the realization of high‐energy‐density, reversible LOBs. Herein, a robust cathode design is proposed for LOBs based on a dual‐phasic carbon nanoarchitecture. The cathode is composed of an interwoven network of porous metal–organic framework (MOF) derived carbon (MOF‐C) and conductive carbon nanotubes (CNTs). The dual‐phasic nanoarchitecture incorporates the advantages of both components: MOF‐C provides a large surface area for the oxygen reactions and a large pore volume for Li2O2 storage, and CNTs provide facile pathways for electron and O2 transport as well as additional void spaces for Li2O2 accommodation. It is demonstrated that the synergistic nanoarchitecturing of the dual‐phasic MOF‐C/CNT material results in promising electrochemical performance of LOBs, as evidenced by a high discharge capacity of ≈10 050 mAh g−1 and a stable cycling performance over 75 cycles.
A dual‐phasic carbon nanoarchitecture based on an interwoven network of metal–organic framework (MOF) derived carbon (MOF‐C) and carbon nanotubes (CNTs) is proposed as a cathode for rechargeable lithium–oxygen batteries. The synergistic nanoarchitecturing of the high surface area, porous MOF‐C, and conductive CNTs leads to a considerable improvement in the specific capacity, rate‐performance, and cycle lifetime of the batteries.
A core–shell structured Si nanoparticles@TiO2–x /C mesoporous microfiber composite has been synthesized by an electrospinning method. The core–shell composite exhibits high reversible capacity, ...excellent rate capability, and improved cycle performance as an anode material for Li-ion batteries. Furthermore, it shows remarkable suppression of exothermic behavior, which can prevent possible thermal runaway and safety problems of the cells. The improved electrochemical and thermal properties are ascribed to the mechanically, electrically, and thermally robust shell structure of the TiO2–x /C nanocomposite encapsulating the Si nanoparticles, which is suggested as a promising material architecture for a safe and reliable Si-based Li-ion battery of high energy density.
The utilization of lithium (Li) metal as an anode has attracted significant attention for high‐energy Li batteries. Unfortunately, uncontrollable Li dendrite cannot be avoided during Li plating and ...stripping. Much intensive research has been conducted to suppress the dendritic growth by confinement of metallic Li in host architectures. Recently, zeolitic imidazolate frameworks (ZIFs) with a porous features have been used to explore a new approach to storing the Li metal with the advantages of their structural and chemical stability, large surface areas, and large pore cavities. Herein, we investigate the storage capability of metallic Li in a porous carbon framework derived from ZIFs as a function of carbonization temperature. Diversities in pore volumes and channels, the degree of crystallinity, the amount of residual zinc (Zn) metal, and the electrical conductivity can all be controlled by temperature. We demonstrate that well‐connected pore channels and adequate electrical conductivity secure the Li‐ion pathways and that well‐distributed Zn clusters in porous carbon trigger the outward growth of metallic Li from inside the frameworks, resulting in a relatively low overpotential and long‐lasting cyclability. Our findings can provide practical insight into advanced electrode design for next‐generation Li metal batteries.
The inherent internal porosity of carbon frameworks derived from ZIF‐8 offers significant pathways for the efficient migration of Li‐ions and provides storage space. The presence of Zn clusters within the porous carbon structures aids in reducing the formation energy, thereby facilitating the growth of Li metal within the internal pores. The overpotential associated with the Li metallization reaction was effectively mitigated due to the low formation energy, ensuring excellent cycling stability by improving reversibility.
Enhancing the mobility of lithium‐ions (Li+) through surface engineering is one of major challenges facing fast‐charging lithium‐ion batteries (LIBs). In case of demanding charging conditions, the ...use of a conventional artificial graphite (AG) anode leads to an increase in operating temperature and the formation of lithium dendrites on the anode surface. In this study, a biphasic zeolitic imidazolate framework (ZIF)‐AG anode, designed strategically and coated with a mesoporous material, is verified to improve the pathways of Li+ and electrons under a high charging current density. In particular, the graphite surface is treated with a coating of a ZIF‐8‐derived carbon nanoparticles, which addresses sufficient surface porosity, enabling this material to serve as an electrolyte reservoir and facilitate Li+ intercalation. Moreover, the augmentation in specific surface area proves advantageous in reducing the overpotential for interfacial charge transfer reactions. In practical terms, employing a full‐cell with the biphasic ZIF‐AG anode results in a shorter charging time and improved cycling performance, demonstrating no evidence of Li plating during 300 cycles under 3.0 C‐charging and 1.0 C‐discharging. The research endeavors to contribute to the progress of anode materials by enhancing their charging capability, aligning with the increasing requirements of the electric vehicle applications.
A biphasic zeolitic imidazolate framework (ZIF)‐artificial graphite (AG) composite as an anode material for a fast‐charging lithium‐ion battery is proposed by directly growing ZIF nanoparticles on the artificial AG surface. The ZIF‐derived carbon nanoparticles act as promoters, facilitating Li+ transport through 3D amorphous carbon channels, thereby improving fast‐charging capabilities and long‐term cycling performance.
Utilizing the unparalleled theoretical capacity of sulfur reaching 1675 mAh/g, lithium–sulfur (Li–S) batteries have been counted as promising enablers of future lithium ion battery (LIB) applications ...requiring high energy densities. Nevertheless, most sulfur electrodes suffer from insufficient cycle lives originating from dissolution of lithium polysulfides. As a fundamental solution to this chronic shortcoming, herein, we introduce a hierarchical porous carbon structure in which meso- and macropores are surrounded by outer micropores. Sulfur was infiltrated mainly into the inner meso- and macropores, while the outer micropores remained empty, thus serving as a “barricade” against outward dissolution of long-chain lithium polysulfides. On the basis of this systematic design, the sulfur electrode delivered 1412 mAh/gsulfur with excellent capacity retention of 77% after 500 cycles. Also, a control study suggests that even when sulfur is loaded into the outer micropores, the robust cycling performance is preserved by engaging small sulfur crystal structures (S2–4). Furthermore, the hierarchical porous carbon was produced in ultrahigh speed by scalable spray pyrolysis. Each porous carbon particle was synthesized through 5 s of carrier gas flow in a reaction tube.
There are increasing demands for large‐scale energy storage technologies for efficient utilization of clean and sustainable energy sources. Solid‐state lithium batteries (SSLBs) based on non‐ or ...less‐flammable solid electrolytes (SEs) are attracting great attention, owing to their enhanced safety in comparison to conventional Li‐ion batteries. Moreover, SSLBs can provide great benefits in terms of battery performance (power and energy densities) and cost when constructed using a bipolar design. In this review, we introduce the general aspects of the bipolar battery architecture and provide a brief overview of the essential components and technologies for bipolar SSLBs: Li+‐conducting SEs, composite electrodes, and bipolar plates. Furthermore, we review the recent progress in the design and construction of bipolar SSLBs with emphasis on the fabrication techniques of SEs and SSLBs and the engineering approaches to improve their electrochemical properties.
Poles apart: Bipolar solid‐state lithium batteries (SSLBs) can provide great benefits in terms of safety, electrochemical performance, and cost. This Review introduces the general aspects of the bipolar architecture and the recent progress in the design and construction of bipolar SSLBs with emphasis on the fabrication techniques of solid electrolytes and SSLBs and the engineering approaches to improve their electrochemical properties.
The use of high-capacity electrode materials (i.e., Si) in Li-ion batteries is hindered by their mechanical degradation. Thus, oxides (i.e., SiO2) are commonly used to obtain high expected capacities ...and long-term cycle performances. Despite extensive studies of the electrochemical–mechanical behaviors of high-capacity energy storage materials, the mechanical behaviors of amorphous SiO2 during electrochemical reaction remain largely unknown. Here, we systematically investigate the stress evolution, electronic structure, and mechanical deformation of lithiated SiO2 through first-principles computation and the finite element method. The structural and thermodynamic role of O in the amorphous Li–O–Si system is reported and compared with that in Si. Strong Si–O bonds in SiO2 show high mechanical strength and brittle behavior, but as Li is inserted, the Li-rich SiO2 phases become mechanically softened. The relaxation kinetics of SiO2, inducing deviatoric inelastic strains under mechanical constraints, is also compared with that of Si. The finite element model including the kinetic model for anisotropic expansion demonstrates that the long-term cycling stability of core–shell Si–SiO2 nanoparticles mainly arises from the reaction kinetics and high mechanical strength of SiO2. These results provide fundamental insights into the chemomechanical behavior of SiO2 for practical use.
Nitrogen-doped turbostratic carbon nanoparticles (NPs) are prepared using fast single-step flame synthesis by directly burning acetonitrile in air atmosphere and investigated as an anode material for ...lithium-ion batteries. The as-prepared N-doped carbon NPs show excellent Li-ion stoarage properties with initial discharge capacity of 596 mA h g–1, which is 17% more than that shown by the corresponding undoped carbon NPs synthesized by identical process with acetone as carbon precursor and also much higher than that of commercial graphite anode. Further analysis shows that the charge–discharge process of N-doped carbon is highly stable and reversible not only at high current density but also over 100 cycles, retaining 71% of initial discharge capacity. Electrochemical impedance spectroscopy also shows that N-doped carbon has better conductivity for charge and ions than that of undoped carbon. The high specific capacity and very stable cyclic performance are attributed to large number of turbostratic defects and N and associated increased O content in the flame-synthesized N-doped carbon. To the best of our knowledge, this is the first report which demonstrates single-step, direct flame synthesis of N-doped turbostratic carbon NPs and their application as a potential anode material with high capacity and superior battery performance. The method is extremely simple, low cost, energy efficient, very effective, and can be easily scaled up for large scale production.
To meet the growing demand for high-power lithium-ion batteries (LIBs), the development of advanced materials is crucial because they play a central role in energy storage technologies. Although ...graphite is widely used as the most popular anode material, the rate capability and thermal stability of graphite should be further improved for extending the applications of LIBs into emerging markets like electric vehicles and personal mobility devices. With this in mind, we propose off-stoichiometric TiO2-x-decorated graphite as a potential anode material for practical use in high-power LIBs. Thanks to the high electrical conductivity and thermal resistance of off-stoichiometric TiO2-x induced by an in situ carbothermal reduction process, the rate capability and thermal stability of graphite can be notably enhanced. The TiO2-x-decorated graphite offers a high capacity retention of 76.9% even after 100 cycles at a current density of 1C. We believe that this work can provide more opportunities to explore highly reliable anode materials offering high-energy and high-power characteristics for advanced LIBs.
A TiO2-x-decorated graphite is synthesized via an in situ carbon thermal reduction process and its feasibility is thoroughly examined as a potential anode material for practical use in high-power LIBs. The high electrical conductivity and thermal resistance of off-stoichiometric TiO2-x decorated on the surface of graphite allow the improvement of rate capability and thermal stability of graphite anode. Display omitted
•A TiO2-x-decorated graphite is synthesized via an in situ carbon thermal reduction process as an anode material for LIBs.•The decoration of TiO2-x nanoparticles is beneficial for improving the rate capability and thermal stability of graphite.•A TiO2-x-decorated graphite offers a stable cycle performance up to 100 cycle at a current density of 1C.
State‐of‐the‐art LiFePO4 technology has now opened the door for lithium ion batteries to take their place in large‐scale applications such as plug‐in hybrid vehicles. A high level of safety, ...significant cost reduction, and huge power generation are on the verge of being guaranteed for the most advanced energy storage system. The room‐temperature phase diagram is essential to understand the facile electrode reaction of LixFePO4 (0 < x < 1), but it has not been fully understood. Here, intermediate solid solution phases close to x = 0 and x = 1 have been isolated at room temperature. Size‐dependent modification of the phase diagram, as well as the systematic variation of lattice parameters inside the solid‐solution compositional domain closely related to the electrochemical redox potential, are demonstrated. These experimental results reveal that the excess capacity that has been observed above and below the two‐phase equilibrium potential is largely due to the bulk solid solution, and thus support the size‐dependent miscibility gap model.
Solid solution phases in LixFePO4 close to x = 0 and x = 1 are successfully isolated at room temperature. Investigation of the isolation processes and isolated phases for various mean particle sizes leads to the verification of the size‐dependent miscibility gap model. Coupled inspections of the equilibrium open‐circuit potential and the lattice dimensions show that the bulk miscibility dominates the electrochemical behavior of LixFePO4.
