Flexible Host Research Articles

Multipocket Cage Enables the Binding of High-Order Bulky and Drug Guests Uncovered by MS Methodology.

Achieving high guest loading and multiguest-binding capacity holds crucial significance for advancement in separation, catalysis, and drug delivery with synthetic receptors; however, it remains a challenging bottleneck in characterization of high-stoichiometry guest-binding events. Herein, we describe a large-sized coordination cage (MOC-70-Zn8Pd6) possessing 12 peripheral pockets capable of accommodating multiple guests and a high-resolution electrospray ionization mass spectrometry (HR-ESI-MS)-based method to understand the solution host-guest chemistry. A diverse range of bulky guests, varying from drug molecules to rigid fullerenes as well as flexible host molecules of crown ethers and calixarenes, could be loaded into open pockets with high capacities. Notably, these hollow cage pockets provide multisites to capture different guests, showing heteroguest coloading behavior to capture binary, ternary, or even quaternary guests. Moreover, a pair of commercially applied drugs for the combination therapy of chronic lymphocytic leukemia (CLL) has been tested, highlighting its potential in multidrug delivery for combined treatment.

Unfolding the Challenges To Prepare Single Crystalline Complex Oxide Membranes by Solution Processing.

The ability to prepare single crystalline complex oxide freestanding membranes has opened a new playground to access new phases and functionalities not available when they are epitaxially bound to the substrates. The water-soluble Sr3Al2O6 (SAO) sacrificial layer approach has proven to be one of the most promising pathways to prepare a wide variety of single crystalline complex oxide membranes, typically by high vacuum deposition techniques. Here, we present solution processing, also named chemical solution deposition (CSD), as a cost-effective alternative deposition technique to prepare freestanding membranes identifying the main processing challenges and how to overcome them. In particular, we compare three different strategies based on interface and cation engineering to prepare CSD (00l)-oriented BiFeO3 (BFO) membranes. First, BFO is deposited directly on SAO but forms a nanocomposite of Sr-Al-O rich nanoparticles embedded in an epitaxial BFO matrix because the Sr-O bonds react with the solvents of the BFO precursor solution. Second, the incorporation of a pulsed laser deposited La0.7Sr0.3MnO3 (LSMO) buffer layer on SAO prior to the BFO deposition prevents the massive interface reaction and subsequent formation of a nanocomposite but migration of cations from the upper layers to SAO occurs, making the sacrificial layer insoluble in water and withholding the membrane release. Finally, in the third scenario, a combination of LSMO with a more robust sacrificial layer composition, SrCa2Al2O6 (SC2AO), offers an ideal building block to obtain (001)-oriented BFO/LSMO bilayer membranes with a high-quality interface that can be successfully transferred to both flexible and rigid host substrates. Ferroelectric fingerprints are identified in the BFO film prior and after membrane release. These results show the feasibility to use CSD as alternative deposition technique to prepare single crystalline complex oxide membranes widening the range of available phases and functionalities for next-generation electronic devices.

Asymmetric Zn-N4 atomic sites embedded hollow fibers as stable Zn anode for high-performance Zn-ion hybrid capacitor

Zn based electrochemical energy storage systems (EES) have attracted tremendous interests owing to their low cost and high intrinsic safety. Nevertheless, the uncontrolled growth of Zn dendrites and the side reactions of Zn metal anodes (ZMAs) severely restrict their applications. To address these issues, we design the asymmetric Zn-N4 atomic sites embedded hollow fibers (AS-IHF) as the flexible host for stable ZMAs. Through introducing different nitrogen resources in the synthesis, two kinds of coordination, i. e. Zn-N (pyridinic) and Zn-N (pyrrolic), are introduced in the Zn-N4 atomic module synchronously. The asymmetric Zn-N4 module with regulated micro-environment facilitates the superior zincophilic features and promotes the Zn adsorption. Meanwhile, the highly porous structure of the hollow fiber effectively reduces local current density, homogenize Zn ion flux, and alleviate structure stress. All the advantages endow the high efficiency and good stability for Zn plating/stripping. Both theoretical and experimental results demonstrate the high reversibility, low nucleation overpotential, and dendrite-free behavior of the AS-IHF@Zn anode, which afford the high stability in high-rate and long-term cycling. Moreover, the solid-state Zn-ion hybrid capacitor (ZIHC) based on AS-IHF@Zn anode shows the high flexibility, reliability, and superior long-term cycling capability in a wide-range of temperatures (−20–25 °C). Therefore, the present work not only gives a new strategy for modulating local environments of single atomic sites, but also propels the development of flexible power sources for diverse electronics.

Somatic mouse models of gastric cancer reveal genotype-specific features of metastatic disease.

Metastatic gastric carcinoma is a highly lethal cancer that responds poorly to conventional and molecularly targeted therapies. Despite its clinical relevance, the mechanisms underlying the behavior and therapeutic response of this disease are poorly understood owing, in part, to a paucity of tractable models. Here we developed methods to somatically introduce different oncogenic lesions directly into the murine gastric epithelium. Genotypic configurations observed in patients produced metastatic gastric cancers that recapitulated the histological, molecular and clinical features of all nonviral molecular subtypes of the human disease. Applying this platform to both wild-type and immunodeficient mice revealed previously unappreciated links between the genotype, organotropism and immune surveillance of metastatic cells, which produced distinct patterns of metastasis that were mirrored in patients. Our results establish a highly portable platform for generating autochthonous cancer models with flexible genotypes and host backgrounds, which can unravel mechanisms of gastric tumorigenesis or test new therapeutic concepts.

Modulating photophysical properties in a flexible porous host by regulating guest-assisted charge transfer interactions.

The 1D array of electron donor-acceptor chromophoric organic molecules is of paramount importance for photovoltaic, catalytic and optoelectronic applications. Herein, we report coordination driven 1D arrays of an electron-donor guest (fluorene, carbazole, dibenzofuran, and dibenzothiophene) and o-phen chelator as an acceptor in a Zn-based porous coordination polymer, {[Zn(o-phen)(ndc)]·DMF} (PCP-1). All the guest-encapsulated PCPs were characterized by performing single-crystal structure determinations and showed emission driven by charge transfer. Exciton binding energies were calculated and correlated with electron-donating capabiliities of the guest molecules.

The effect of host size on binding in host-guest complexes of cyclodextrins and polyoxometalates.

Harnessing flexible host cavities opens opportunities for the design of novel supramolecular architectures that accommodate nanosized guests. This research examines unprecedented gas-phase structures of Keggin-type polyoxometalate PW12O40 3- (WPOM) and cyclodextrins (X-CD, X = α, β, γ, δ, ε, ζ) including previously unexplored large, flexible CDs. Using ion mobility spectrometry coupled to mass spectrometry (IM-MS) in conjunction with molecular dynamics (MD) simulations, we provide first insights into the binding modes between WPOM and larger CD hosts as isolated structures. Notably, γ-CD forms two distinct structures with WPOM through binding to its primary and secondary faces. We also demonstrate that ε-CD forms a deep inclusion complex, which encapsulates WPOM within its annular inner cavity. In contrast, ζ-CD adopts a saddle-like conformation in its complex with WPOM, which resembles its free form in solution. More intriguingly, the gas-phase CD-WPOM structures are highly correlated with their counterparts in solution as characterized by nuclear magnetic resonance (NMR) spectroscopy. The strong correlation between the gas- and solution phase structures of CD-WPOM complexes highlight the power of gas-phase IM-MS for the structural characterization of supramolecular complexes with nanosized guests, which may be difficult to examine using conventional approaches.

Flexible self-supporting interconnected cobalt sulfide nanosheets enable high-loading and long-cycling Li-S batteries with high areal capacity

Lithium-sulfur batteries (LSB) with high theoretical specific capacity/energy density still face some practical challenges, for instance shuttle effect and sluggish redox kinetics, which leads to rapid capacity decay. To overcome these challenges, herein, a porous and flexible sulfur host composed of interconnected Co9S8 nanosheets grown on carbon cloth was constructed. The interconnected carbon fiber skeleton and porous conductive Co9S8 nanosheets can not only provide abundant electron/ion-transport channels, but also offer adequate void to accommodate volume expansion of sulfur, thus ensuring high sulfur utilization and remarkable cycle stability of electrode. Meanwhile, the abundant adsorption and catalytic sites provided by Co9S8 nanosheets can effectively inhibit dissolution of polysulfides and improve conversion kinetics of polysulfides, effectively suppressing “shuttle effect”. The Co9S8-CC/Li2S6 electrode achieves high discharge capacity (1315.1 mAh g−1, 0.1C), excellent rate capability (872.4 mAh g−1, 2C) and outstanding cyclic stability (decay of 0.02 %/cycle over 1500 cycles, 2C).

Porous Carbon Textile Decorated with VC/V2O3-X Hybrid Nanoparticles: Dual-Functional Host for Flexible Li-S Full Batteries

The polysulfide shuttling at the cathode and lithium dendrite formation at the anode remain as major obstacles to overcome for the realization of high-performance lithium-sulfur (Li-S) batteries. Here, via a facile one-pot synthesis using carbothermic reduction, we prepared a porous and flexible carbon textile uniformly decorated with VC/V2O3-x hybrid nanoparticles, which was used as a robust and flexible host material for both sulfur cathode and Li metal anode. We observed that the defective V2O3-x part traps polysulfides and the conductive VC part catalytically enhances the fragmentation of the polysulfides. Moreover, it was found that the well-distributed VC/V2O3-x nanoparticles act as lithiophilic sites to lead uniform lithium nucleation for a dendrite-free lithium metal anode. The full battery delivered superb rate performance (882 mAh g − 1 at 5 C) and an ultralow decay rate of 0.02% per cycle during 1000 cycles at 1 C. Even with a large sulfur loading of 7.0 mg cm−2, a high areal capacity of 6.29 mAh cm−2 at 0.2 C was obtained. This work provides an effective remedy to simultaneously resolve problems regarding the shuttle effect and the Li dendrite formation for the realization of high-performance flexible Li-S full batteries.

Semi-Embedded Structured Bi Nanospheres for Boosted Self-Heating-Induced Healing of Li-Dendrites.

It is reported that self-heating-induced healing on lithium metal anodes (LMAs) provides a mitigation strategy for suppressing Li dendrites. However, how to boost the self-heating-induced healing of Li-dendrites and incorporate it into Li-hostdesign remains an imminent problem that needs to be solved. Herein, a new bismuth nanosphere semi-buried carbon cloth (Bi-NS-CC) material with a 3D flexible host structure is proposed. The ultrasmall Bi nanospheres are uniformly and densely distributed on carbon fiber, providing active sites to form uniform Li3 Bi alloy with molten lithium, thereby guiding the injection of molten metallic lithium into the 3D structure to form a self-supporting composite LMAs. The ingenious semi-embedded structure with strong interfacial C─Bi ensures superior mechanical properties. Interestingly, when the current density reaches up to 10mAcm-2 , the lithium dendrites undergo self-heating. Carbon cloth as a host can quickly and uniformly transfer heat, which induces the uniform migration of Li on anodes. The semi-embedded structure with strong C─Bi ensures Bi nanospheres guide the formation of smooth morphology even under these harsh conditions (high-temperature, high-rate, etc.). Consequently, at 10mAcm-2 /10mAhcm-2 , the Li/Li3 Bi-NS-CC realizes ultra-long cycles of 1500h and ultra-low overpotential of 15mV in a symmetric cell.

PTFE nanofiber cross-linked acetylene black: A flexible self-supporting semi-confined architecture for ultra-high sulfur loading and areal capacity

Lithium-sulfur batteries attract great interest due to their high energy density, sulfur abundance and environment friendly. However, the shuttle effect of lithium polysulfide and serious capacity fading especially at high sulfur loading remains a challenge for their commercial applications. In this work, we propose a scalable and feasible strategy to construct a flexible host for sulfur and catalyst carrier, in which polytetrafluoroethylene is employed as a precursor and in-situ polymerized into nanofibers to link acetylene black (PTFE NF/AB) through a blend and low temperature (∼ 180 °C) treatment process. The PTFE NF/AB exhibits semi-confined architecture for sulfur accommodation, electrolyte infiltration and electron transformation. Impressively, the electrode achieves a high areal capacity of 14.6 mAh cm−2 at the current density of 4.82 mA cm−2 with a sulfur loading of 20.6 mg cm−2. Moreover, the PTFE NF/AB architecture can be employed as the catalyst supports. The capacity can be further enhanced to 17.4 mAh cm−2 when MoS2 fabricated into the PTFE NF/AB using a ball mill approach. Assembled into a pouch cell, the PTFE NF/AB architecture delivers a high capacity of 825.4 mAh g−1 in the folded state, showing its excellent potential in the high-energy flexible territory.

Commensal protists in reptiles display flexible host range and adaptation to ectothermic hosts.

Environmental factors like climate change and captive breeding can impact the gut microbiota and host health. Therefore, conservation efforts for threatened species may benefit from understanding how these factors influence animal microbiomes. Parabasalid protists are members of the mammalian microbiota that can modulate the immune system and impact susceptibility to infections. However, little is known about parabasalids in reptiles. Here, we profile reptile-associated parabasalids in wild and captive reptiles and find that captivity has minimal impact on parabasalid prevalence or diversity. However, because reptiles are cold-blooded (ectothermic), their microbiotas experience wider temperature fluctuation than microbes in warm-blooded animals. To investigate whether extreme weather patterns affect parabasalid-host interactions, we analyzed the gene expression in reptile-associated parabasalids and found that temperature differences significantly alter genes associated with host health. These results expand our understanding of parabasalids in this vulnerable vertebrate group and highlight important factors to be taken into consideration for conservation efforts.

Binding Thermodynamics of Ferrocenyl Ammoniums by Sulfonated Calix[4]arenes

AbstractThe binding constants (Ka), standard molar enthalpy changes (ΔH°), and entropy changes (TΔS°) between two sulfonated calix[4]arene hosts including rigid p‐sulfonatocalix[4]arene (SC4A) and flexible p‐sulfonatothiacalix[4]arene (STC4A), and three ferrocenyl ammonium guests modified by different aliphatic chains were determined in aqueous solution (pH 7.0 and pH 2.0) by isothermal titration microcalorimetry (ITC). The gained data indicated that for the flexible host STC4A, the host‐guest binding affinities increased with the increase of length of the aliphatic chain of guests whereas the rigid host SC4A behaved almost oppositely. Compared with those at pH 2.0, the binding affinities between the hosts and the guests were much stronger at pH 7.0. This should be attributed to the higher π‐electron density and the extra negative charge of calixarene cavities owing to one of the phenolic hydroxyl groups is deprotonated at pH 7.0, thus affording stronger π⋯π, C−H⋯π and electrostatic interactions. Job plot and ITC confirmed that the molecular binding were stoichiometric 1 : 1 between hosts and guests. NMR experiments showed that the signals of the guest protons with addition of hosts underwent pronounced upfield shifts suggesting the effective binding between hosts and guests. In addition, the molecular selective binding behavior was discussed from the perspective of thermodynamics.

Three-Dimensional Zinc-Seeded Carbon Nanofiber Architectures as Lightweight and Flexible Hosts for a Highly Reversible Zinc Metal Anode.

Uneven zinc (Zn) deposition typically leads to uncontrollable dendrite growth, which renders an unsatisfactory cycling stability and Coulombic efficiency (CE) of aqueous zinc ion batteries (ZIBs), restricting their practical application. In this work, a lightweight and flexible three-dimensional (3D) carbon nanofiber architecture with uniform Zn seeds (CNF-Zn) is prepared from bacterial cellulose (BC), a kind of biomass with low cost, environmental friendliness, and abundance, as a host for highly reversible Zn plating/stripping and construction of high-performance aqueous ZIBs. The as-prepared 3D CNF-Zn with a porous interconnected network significantly decreases the local current density, and the functional Zn seeds provide uniform nuclei to guide the uniform Zn deposition. Benefiting from the synergistic effect of Zn seeds and the 3D porous framework in the flexible CNF-Zn host, the electrochemical performance of the as-constructed ZIBs is significantly improved. This flexible 3D CNF-Zn host delivers a high and stable CE of 99.5% over 450 cycles, ensuring outstanding rate performance and a long cycle life of over 500 cycles at 4 A g-1 in the CNF-Zn@Zn//NaV3O8·1.5H2O full battery. More importantly, owing to the flexibility of the 3D CNF-Zn host, the as-assembled pouch cell shows outstanding mechanical flexibility and excellent energy storage performance. This strategy of producing readily accessible carbon from biomass can be employed to develop advanced functional nanomaterials for next-generation flexible energy storage devices.

Metal–Organic Framework-Derived NiO@C as a Host for MnO2 Cathode of Stable Zinc-Ion Batteries

MnO2 has been regarded as one of the most promising cathode materials for safe and inexpensive aqueous Zn-ion batteries (AZIBs). However, the severe Mn dissolution upon cycling is a major challenge for their practical application. Herein, we prepared a flexible and carbonaceous host for the MnO2 cathode in the form of metal–organic framework-derived nanoporous carbon decorated with NiO nanoparticles. The NiO nanoparticle-encapsulated carbon as a helpful additive led to a synergistic effect with MnO2. The MnO2 hosted on the flexible support allowed the construction of AZIB with a high capacity (330 mAh/g after 250 cycles at 0.625 A/g) and good cyclic performance (74.4% retention after 1500 cycles at 3.75 A/g). It is believed that the structural transformation of β-MnO2 (MnO2 → Mn2+ → birnessite MnOx) and the reversible (de)insertion of Zn2+ into NiO (NiO ↔ ZnxNiO) play a key role in the high capacity and cyclic stability of the prepared AZIBs. Our approach holds great promise to design various hosts for MnO2-based cathodes of AZIBs.

Tuning the structure characteristic of the flexible covalent organic framework (COF) meets a high performance for lithium-sulfur batteries

Rigid-based covalent organic frameworks (COFs) are always employed as sulfur-redox/confined host for adapting its varied states upon cycling of highly effective Li-S batteries. Restricted by the unalterable structure frameworks of rigid COFs, flexible COFs are considered to reserve greater capability in coping with active sulfur to meet higher energy demands, while no flexible COF host has been employed currently. In this work, flexible-based COFs with triazine-ring organic macromolecule blocks (COF-TPT(OH) and COF-TPT) are designed and developed as the host materials of Li-S batteries. The structural diversity of flexible-based COF could provoke the phenomenon of capacity increase, which endows the COF-TPT(OH)@S electrode with a high reversible capacity of 1100 mAh g-1 after 80 cycles at 0.1 C. Even after 1000 cycles at 0.5 C, it can still deliver 732 mAh g−1 with a low decay rate of 0.045 % per cycle. Moreover, the introduction of hydroxyl groups (-OH) equips COF-TPT(OH) with the characteristics of both rigid- and flexible- COFs, contributing to the enhanced abilities of the polysulfides conversion and limitation. Our findings will provide a new idea for the selection of host materials for Li-S batteries.

Carbonized Bacterial Cellulose-Derived Binder-Free, Flexible, and Free-Standing Cathode Host for High-Performance Stable Potassium–Sulfur Batteries

In search of improved advanced energy storage systems to meet our fast-growing energy demands for large-scale applications, potassium–sulfur batteries (KSBs) provide an essential alternative due to their high specific capacity apart from the low cost and abundance of potassium and sulfur. However, the insulating nature of sulfur, volume changes, and shuttle effect impede the development of these batteries. Further, the binder, carbon additives, and current collector used in the assembly of cells in a conventional approach decrease the energy density of cells. To overcome these challenges, we propose a binder-free and free-standing carbonized bacterial cellulose (CBC) as a cathode host that not only provides a conducting pathway but also has a porous network that is resilient to volume change. To ensure the uniform loading of sulfur, CBC was dipped into the sulfur/carbon disulfide solution, followed by melt diffusion at 160 °C to prepare a sulfur-infused CBC (S-CBC) cathode. This S-CBC cathode with an interconnected fiber network delivers a significantly high reversible capacity of 1311 mA h g–1 at a current density of 50 mA g–1. While connected for long-term cycling, the potassium sulfur cell delivers an initial reversible capacity of 475 mA h g–1 at 100 mA g–1. Once the cell is stabilized after 80 cycles, it maintains a capacity of 123 mA h g–1 with a capacity retention of 86% after 500 cycles. This enhanced electrochemical performance of flexible and free-standing S-CBC cathode is further analyzed using first-principles calculations. Moreover, the efficacy of the S-CBC cathode is also tested under high sulfur loading (1.6 and 2.4 mg cm–2, respectively) for the practical development of KSBs.

Corralarenes: A Family of Conjugated Tubular Hosts.

Despite the advances in host-guest chemistry, macrocyclic hosts with deep cavities are far from abundant among the large number of wholly synthetic hosts described in the literature. Herein, we describe the design and synthesis of two new tubular hosts, namely, corral[4]arene and corral[5]arene. The former has been isolated and characterized as two conformational diastereoisomers, one is centrosymmetric and the other asymmetric. The latter, a fivefold symmetrical and flexible host, has also been investigated in detail. It is composed of five 4,4'-dimethoxybiphenyl units bridged by ethynylene linkers at their 2,2'-positions and adopts a pentagonal conformation with a tubular-shaped cavity in the presence of guests. This structure endows corral[5]arene not only with a conjugated backbone, capable of bright fluorescent emission (quantum yield, 56%), but also a deep π-electron-rich aromatic cavity with remarkable conformational flexibility. The adaptive cavity of corral[5]arene allows it to accommodate a wide range of neutral and positively charged electron-deficient guests with different molecular sizes and shapes. Binding constants between this host and these guests in three different nonpolar organic solvents lie in the range of 103 to 107 M-1. Moreover, corral[5]arene exhibits dynamic chirality on account of the axes of chirality associated with each of the five biphenyl units and displays first-order transformation as exhibited by circular dichroism in response to the addition of chiral guests. All these stereochemical features render corral[5]arene an attractive host for a variety of supramolecular and nanotechnological applications.

Stabilizing Li metal anode by constructing lithiophilic N-doped carbon nanotubes on flexible carbon felt host

The Li metal anode is regarded as the most ideal anode material for the next-generation high-energy-density rechargeable Li batteries. Unfortunately, infinite volume change, “dead” Li formation, and continuous dendrite growth, severely hamper its commercial applications. Constructing 3D hosts has been widely developed to address these issues. Herein, nitrogen-doped carbon nanotubes (NCNTs) are grown in the carbon felt (CF) as the host material for Li metal anode via economic chemical vapor deposition was developed. Carbon felt provides a fast and uniform ion/electron pathway and alleviates the volume expansion during the charge/discharge process. With the introduction of NCNTs, lithiophilic functional groups like pyridine and pyrrole distributed uniformly on the surface of carbon felt, providing adequate lithiophilic sites to guide Li nucleation, ensuring the smooth Li deposition with dendrite-free morphology. As a result, excellent cycling stability is realized in symmetric cells with low overpotential and long lifespan. In addition, when the composite Li electrode is paired with the sulfur cathode (8.7 mg cm−2), the full cell displays a steady cycle life in coulombic efficiency retention of 93 % and a high specific capacity of 3.32 mAh cm−2 after 270 cycles at 0.2C.

Multi-functional bilayer carbon structures with micrometer-level physical encapsulation as a flexible cathode host for high-performance lithium-sulfur batteries

With the exceptional merits of high energy density, low cost, and environmental friendliness, lithium-sulfur batteries are considered to be one of the most promising next-generation flexible rechargeable batteries. However, the notorious “shuttle effect” has seriously hindered their practical applications. Herein, a strategy for designing multi-functional bilayer carbon structures is proposed, specifically, by employing a micrometer-thick graphene nanoflowers (GF) layer to encapsulate a micrometer-scale hybrid network skeleton composed of metallic Co and carbon nanotubes (CNT) as a flexible sulfur cathode host (Co/CNT@GF). Beneficial from the merits of chemical adsorption, electrocatalysis and volume expansion mitigation from the internal skeleton as well as the micrometer-level physical domain confinement by the external GF layer, the developed host could chemically trap, electrochemically catalyze, physically block and storage the lithium polysulfides. Due to the synergistic effect of these functions, the Co/CNT@GF-S delivers a superior discharge capacity of 799 mAh g−1 with a decay rate as low as 0.08 % per cycle after 400 cycles at 1 C. Even at a high sulfur loading of 8.16 mg cm−2, the average discharge capacity is as high as 5.05 mAh cm−2 in 100 cycles. This work does not only contribute to the rational design of multi-functional bilayer structures but also offers a novel design method for the commercialization of flexible lithium-sulfur batteries with high-energy–density.

Amorphous hollow carbon film as a flexible host for liquid Na-K alloy anode

Compared with solid alkali metal anodes (Li, Na, K), liquid metal anodes (LMAs) could enable high-energy batteries due to their unique advantages, such as self-healing property and no dendrites. Among LMAs, liquid Na-K alloy anode has become a hotspot due to its high theoretical capacity, low redox potential and formation at room temperature (RT). However, it is challenging to utilize liquid Na-K alloy directly and independently as an electrode; and the high surface tension makes it more difficult to immerse into porous current collectors at RT. Herein, an amorphous hollow carbon film (AHCF) consisting of hollow spheres with significant surface defects has been designed to quickly infiltrate Na-K liquid alloy into the hollow carbon film at RT, forming a composite electrode (Na-K@AHCF). The symmetric cell with Na-K@AHCF could exhibit a cycle lifespan up to 400 h at 0.1 mA/cm2 and achieve stable stripping/deposition even at 5 mA/cm2. When matching with cathode material of sulfurized polyacrylonitrile (SPAN), the obtained K-S full cell exhibits good cycle stability and rate performance.