Lithium (Li) metal is regarded as the most attractive anode material for high‐energy Li batteries, but it faces unavoidable challenges—uncontrollable dendritic growth of Li and severe volume changes ...during Li plating and stripping. Herein, a porous carbon framework (PCF) derived from a metal–organic framework (MOF) is proposed as a dual‐phase Li storage material that enables efficient and reversible Li storage via lithiation and metallization processes. Li is electrochemically stored in the PCF upon charging to 0 V versus Li/Li+ (lithiation), making the PCF surface more lithiophilic, and then the formation of metallic Li phase can be induced spontaneously in the internal nanopores during further charging below 0 V versus Li/Li+ (metallization). Based on thermodynamic calculations and experimental studies, it is shown that atomically dispersed zinc plays an important role in facilitating Li plating and that the reversibility of Li storage is significantly improved by controlled nanostructural engineering of 3D porous nanoarchitectures to promote the uniform formation of Li. Moreover, the MOF‐derived PCF does not suffer from macroscopic volume changes during cycling. This work demonstrates that the nanostructural engineering of porous carbon structures combined with lithiophilic element coordination would be an effective approach for realizing high‐capacity, reversible Li‐metal anodes.
A porous carbon nanoarchitecture derived from metal–organic frameworks is strategically suggested as a dual‐phase lithium (Li) storage host for Li‐metal batteries. Controlled open pores are highly desired for providing abundant free spaces for metallization of Li and atomically dispersed zinc metal and nitrogen play an important role in enhancing affinity toward Li+ and electrical conductivity during Li plating–stripping without any structural degradation.
A rechargeable lithium–oxygen battery (LOB) operates via the electrochemical formation and decomposition of solid-state Li
2
O
2
on the cathode. The rational design of the cathode nanoarchitectures ...is thus required to realize high-energy-density and long-cycling LOBs. Here, we propose a cathode nanoarchitecture for LOBs, which is composed of mesoporous carbon (MPC) integrated with carbon nanotubes (CNTs). The proposed design has the advantages of the two components. MPC provides sufficient active sites for the electrochemical reactions and free space for Li
2
O
2
storage, while CNT forests serve as conductive pathways for electron and offer additional reaction sites. Results show that the synergistic architecture of MPC and CNTs leads to improvements in the capacity (~ 18,400 mAh g
− 1
), rate capability, and cyclability (~ 200 cycles) of the CNT-integrated MPC cathode in comparison with MPC.
The strategic design of the cathode is a critical feature for high-performance and long-lasting reversibility of an energy storage system. In particular, the round-trip efficiency and cycling ...performance of nonaqueous lithium-oxygen batteries are governed by minimizing the discharge products, such as LÍ2O and LÍ2O2. Recently, a metal-organic framework has been directly pyrolyzed into a carbon frame with controllable pore volume and size. Furthermore, selective metallic catalysts can also be obtained by adjusting metal ions for outstanding electrochemical reactions. In this study, various bimetallic zeolitic imidazolate framework (ZIF)-derived carbons were designed by varying the ratio of Zn to Co ions. Moreover, carbon nanotubes (CNTs) are added to improve the electrical conductivity further, ultimately leading to better electrochemical stability in the cathode. As a result, the optimized bimetallic ZIF-carbon/CNT composite exhibits a high discharge capacity of 16.000 mAh-g-1. with a stable cycling performance of up to 137 cycles. This feature is also beneficial for lowering the overpotential of the cathode during cycling, even at the high current density of 2.000 mA-g-1.
•Metal–organic framework-based interfacial modifier for biphasic solid electrolytes.•The nanoporous metal–organic framework layer homogenizes the Li+ flux.•The interfacial modifier forms stable ...interfaces with intimate solid–solid contact.•The solid electrolyte with the interfacial modifier enables stable cycling.
Solid-state lithium batteries (SSLBs) based on non-flammable inorganic solid electrolytes have been proposed as promising technical solutions to resolve safety issues caused by flammable organic liquid electrolytes of current Li-ion batteries. Biphasic solid electrolytes (BSEs) comprising Li+-conducting oxides and polymers have garnered significant interest for SSLBs because of their mechanical robustness and high Li+ conductivity. However, the non-uniform distribution of oxide particles and polymer species in BSEs may cause inhomogeneous Li+ conduction, thereby resulting in poor interfacial stability with electrodes during repeated charge–discharge cycles. Herein, we report a Li7La3Zr2O12-based BSE with homogeneous Li+ transport pathways achieved by a metal–organic framework (MOF) layer. To regulate and homogenize the Li+ flux across the interface between the BSE and electrode, a free-standing BSE is integrated with the MOF layer. The MOF-integrated BSE forms smooth and uniform interfaces with nanoporous channels in contact with the electrodes, effectively enhancing the interfacial solid–solid contact and facilitating homogeneous Li+ transport. An SSLB with the MOF-BSE membrane shows enhanced cycling stability and rate-capability compared to the battery with bare BSE. This study demonstrates that the proposed electrolyte design provides an effective approach for improving the conducting properties and interfacial stability of BSEs for high-performance and long-cycling SSLBs.
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The crucial issue of wettability in high-energy-density lithium-ion batteries (LIBs) has not been comprehensively addressed to date. To overcome the challenge, state-of-the-art LIBs employing a ...ceramic-coated separator improves the safety- and wettability-related aspects of LIBs. Here, we present a mechanistic study of the effects of a ceramic-coated layer (CCL) on electrode wettability and report the optimal position of the CCL in LIBs. The electrolyte wetting was investigated using the multiphase lattice Boltzmann method and electrochemical impedance spectroscopy for capturing the electrolyte-transport dynamics in porous electrodes and impedance spectra in pouch-type LIBs, respectively. Results indicate that the CCL caused the velocity vector to transport the electrolyte further, resulting in an increase in the wetting rate. Moreover, the location of the CCL considerably affected the wettability of the LIBs. This study provides mechanical insight into the design and fabrication of high-performance LIBs by incorporating CCLs.
•Conflicting roles of conductive additives in all-solid-state batteries are studied.•Conductive additives are effective for enhancing electronic transport.•Conductive additives make the ionic ...transport and interfacial reaction sluggish.•Critical cell degradation factors are identified by impedance decoupling.•The compatibility between the conductive additive and solid electrolyte is crucial.
Sulfide-based all-solid-state batteries (ASSBs) have recently attracted significant attention owing to the high ionic conductivities and mechanical ductilities of sulfide solid electrolytes (SEs). In general, carbon-based conductive additives (CAs) are incorporated into solid composite electrodes to enable facile electronic transport and to enhance active-material (AM) utilization. Herein, we reveal the conflicting roles of the one-dimensional (1D) CA (vapor-grown carbon fibers) in determining the electrochemical performance of composite electrodes with high AM fraction (fAM) (i.e., low SE fraction) based on impedance decoupling analyses. The CA provides a beneficial effect on the performance of the low-fAM electrode (fAM = 72 wt%) by reducing its electronic resistance, whereas the CA-incorporated high-fAM electrode (fAM = 88 wt%) shows inferior rate-capability and severe capacity decay compared to the CA-free electrode. In-depth impedance decoupling analyses indicate that in high-fAM electrodes with high CA-to-SE ratios, the CA makes the ionic pathway tortuous and accelerates the formation of SE-derived resistive phases, thus nullifying the benefits of enhanced electronic transport. In addition to the construction of optimized charge transport pathways, this study highlights the importance of the compatibility between the CA and SE, which is experimentally demonstrated by high-fAM electrodes with halide-type SEs.
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•Metal–organic framework-derived carbon on a Ag-coated substrate for Li anodes.•The lithiophilic Ag layer on the substrate improves the cycling stability.•A strong Li–substrate ...interaction promotes confined Li metal storage in the anode.•Kinetic competition between Li+ transport and the interfacial reaction.•The Li–substrate interaction is a key design factor for porous carbon frameworks.
Li metal suffers from uncontrollable dendrite formation and huge volume changes during cycling, resulting in shortened cycle lifetimes. Porous carbon frameworks have been explored as host materials to store Li metal; however, the low pore utilization and uneven Li plating remain crucial issues. Herein, we demonstrate that a strong interaction between Li and substrate plays a critical role in enhancing pore utilization in the carbon framework electrodes, thus improving their cycle lifetimes. As a model architecture, we examine a Li storage process in a framework electrode consisting of porous carbon derived from metal–organic frameworks (MOFs) and a galvanically displaced Ag layer on a Cu substrate. The MOF-derived carbon framework electrode on the Ag-deposited Cu substrate exhibits significantly better cycling stability (>250 cycles) than the electrode on bare Cu (140 cycles). In-operando synchrotron X-ray diffraction studies combined with microstructural characterizations reveal that the lithiophilic Ag on the substrate preferentially reacts with Li+ to form LixAg during the initial stage of Li plating and promotes confined Li storage in the carbon framework electrode while suppressing top plating. However, the Ag layer is found to lose its effectiveness when the thickness of the electrode exceeds a critical value. Based on simulation studies, the efficacy of lithiophilic layers toward improving pore utilization is discussed in terms of the kinetic competition between Li+ transport through porous channels and the interfacial reaction of Li+ with the substrate, which can provide a guideline for designing porous carbon frameworks with high capacity and long cycle lifetimes.
Li metal has been regarded as a promising anode for rechargeable batteries with high energy densities. However, the growth of Li dendrites and severe volume changes in the Li anode still hinder its ...practical use. Three-dimensional (3D) host structures have recently attracted significant attention as an effective strategy to resolving these problems. Herein, we demonstrate reversible Li metal storage in carbon hosts with strong Li–host interactions derived from metal-organic frameworks (MOFs). The combined experimental and computational modeling studies reveal that galvanically displaced Ag enhances Li–host interactions and the spatial distribution characteristics of Ag play a crucial role in controlling Li storage behavior and reversibility. The atomic Ag clusters trigger the outward growth of Li from the internal pores of the host and enables stable battery cycling, whereas the surface-anchored Ag nanoparticles induce uneven Li plating on the outer surface of the carbon host, resulting in a rapid performance drop. This work provides new insights into the development of advanced host materials for reversible Li anodes by utilizing strong Li–host interactions.
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•Metal-organic framework-derived carbon hosts with galvanically introduced Ag.•Lithiophilic Ag enhances the Li–host interaction, inducing preferential Li plating.•Atomic Ag clusters in the carbon host improve the cycling stability.•Surface-anchored Ag particles cause uneven Li plating and a fast performance drop.•The morphology and distribution of lithiophilic Ag determines Li plating behavior.
Three-dimensional (3D) porous frameworks have attracted considerable interest as lithium-metal electrodes for next-generation rechargeable batteries. The high surface areas and large pore volumes of ...3D frameworks are beneficial for reducing local current densities and suppressing volume changes. However, uneven Li plating on top of the framework electrode (top growth) has yet to be resolved. To enable the bottom-up Li growth while suppressing the top growth, herein, we propose a rational design of 3D framework electrodes with an interfacial activity gradient (IAG) based on a kinetics-based mechanistic analysis. A simulation demonstrates that an IAG design promotes the bottom-up Li growth, which is experimentally proven using model architectures. The IAG-Cu framework shows considerable improvements in morphological stability and reversibility during high-capacity Li storage, compared to the Cu framework with a uniform interfacial activity. This work provides fundamental insight into the design of 3D frameworks to boost the cycling stability of Li-metal batteries.
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•An organic liquid electrolyte-free cathode design is proposed for Li–O2 batteries.•The cathode design involves a duplex-structured Li+-selective solid membrane.•The duplex-structured ...membrane mitigates the degradation of the metallic Li anode.•The Au-decorated carbon nanotube forests serve as catalytically active sites.•The unique cell architecture results in improved stability during cycling.
Ether-based organic liquid electrolytes (OLEs) have been commonly used in lithium–oxygen batteries (LOBs); however, they become unstable and cause rapid performance degradation during LOB operation. To address these problems, in this study we propose an OLE-free cathode architecture based on a Li+-selective solid membrane (LSSM). An LSSM with a seamless duplex (dense/porous) architecture is prepared by a tape casting process combined with co-sintering, and carbon nanotubes (CNTs) decorated with Au nanoparticles (CNT@Au) are directly formed on its porous framework. We show that the duplex-LSSM can effectively protect the metallic Li anode from parasitic reactions with impurity species and improve the cycling stability of Li. Furthermore, an LOB assembled with the duplex-LSSM and CNT@Au components exhibits a discharge capacity as high as 3650mAhg−1 and improved cycling stability (>140 cycles) compared to a conventional OLE-based LOB; this can be explained in terms of the combined advantages provided by the OLE-free cathode and the LSSM-protected Li anode.
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