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A stable anode‐free lithium metal battery (AFLMB) is accomplished by the adoption of a facile fabricated amorphous antimony (Sb)‐coated separator (SbSC). The large specific surface area of the separator elevates lithium (Li)‐Sb alloy kinetic, improving Li wetting ability on pristine copper current collector (Cu). When tested with LiNi0.8Mn0.1Co0.1O2 (NMC811) as cathode, the full cell with SbSC demonstrates low nucleation overpotential with compact, dendrite‐free and homogeneous Li plating, and exhibits a notable lithium inventory retention rate (LIRR) of 99.8 % with capacity retention of 93.6 % after 60 cycles at 0.5 C‐rate. Conversely, full cells containing pristine separator/Cu (i. e., SC) and pristine separator/Sb‐coated current collector (i. e., SSbC) display poor cycling performances with low LIRRs. Density functional theory corroborates the nucleation behaviours observed during in‐situ half‐cell Li deposition. Functionalizing polymeric separator by metallic coating in AFLMB is a novel approach in improving the cycle life of an AFLMB by promoting homogeneous Li plating behavior. This innovative approach exemplifies a promising applicability for uniform Li‐plating behavior to achieve a longer cycle life in AFLMB. [ABSTRACT FROM AUTHOR]

The catalytic performance of metal–organic frameworks (MOFs) in Li‐S batteries is significantly hindered by unsuitable pore size, low conductivity, and large steric contact hindrance between the catalytic site and lithium polysulfide (LPSs). Herein, the smallest π‐conjugated hexaaminobenzene (HAB) as linker and Ni(II) ions as skeletal node are in situ assembled into high crystallinity Ni‐HAB 2D conductive MOFs with dense Ni‐N4 units via dsp2 hybridization on the surface of carbon nanotube (CNT), fabricating Ni‐HAB@CNT as separator modified layer in Li‐S batteries. As‐obtained unique π‐d conjugated Ni‐HAB nanostructure features ordered micropores with suitable pore size (≈8 Å) induced by HAB ligands, which can cooperate with dense Ni‐N4 chemisorption sites to effectively suppress the shuttle effect. Meanwhile, the conversion kinetics of LPSs is significantly accelerated owing to the small steric contact hindrance and increased delocalized electron density endued by the planar tetracoordinate structure. Consequently, the Li‐S battery with Ni‐HAB@CNT modified separator achieves an areal capacity of 6.29 mAh cm−2 at high sulfur loading of 6.5 mg cm−2 under electrolyte/sulfur ratio of 5 µL mg−1. Moreover, Li‐S single‐electrode pouch cells with modified separators deliver a high reversible capacity of 791 mAh g−1 after 50 cycles at 0.1 C with electrolyte/sulfur ratio of 6 µL mg−1. [ABSTRACT FROM AUTHOR]

Abstract The catalytic performance of metal–organic frameworks (MOFs) in Li‐S batteries is significantly hindered by unsuitable pore size, low conductivity, and large steric contact hindrance between the catalytic site and lithium polysulfide (LPSs). Herein, the smallest π‐conjugated hexaaminobenzene (HAB) as linker and Ni(II) ions as skeletal node are in situ assembled into high crystallinity Ni‐HAB 2D conductive MOFs with dense Ni‐N4 units via dsp2 hybridization on the surface of carbon nanotube (CNT), fabricating Ni‐HAB@CNT as separator modified layer in Li‐S batteries. As‐obtained unique π‐d conjugated Ni‐HAB nanostructure features ordered micropores with suitable pore size (≈8 Å) induced by HAB ligands, which can cooperate with dense Ni‐N4 chemisorption sites to effectively suppress the shuttle effect. Meanwhile, the conversion kinetics of LPSs is significantly accelerated owing to the small steric contact hindrance and increased delocalized electron density endued by the planar tetracoordinate structure. Consequently, the Li‐S battery with Ni‐HAB@CNT modified separator achieves an areal capacity of 6.29 mAh cm−2 at high sulfur loading of 6.5 mg cm−2 under electrolyte/sulfur ratio of 5 µL mg−1. Moreover, Li‐S single‐electrode pouch cells with modified separators deliver a high reversible capacity of 791 mAh g−1 after 50 cycles at 0.1 C with electrolyte/sulfur ratio of 6 µL mg−1.

Lithium (Li) metal anodes have received intensive attention owing to its high specific capacity and low redox potential. However, chronic issues related to dendritic Li growth have hindered the pragmatic use of Li-metal batteries (LMBs). As one of feasible approaches, depositing a functional material on the separator is an efficient strategy for improving the electrochemical stability of LMBs. In this paper, we report a functionalized separator, comprising a nitrided niobium dioxide (named as n-NbO2) and a polypropylene (PP) separator. It is identified that niobium oxide interact with metallic Li, resulting in redistributing the localized Li ion. The n-NbO2-coated separator with enhanced electrical conductivity promotes Li plating/stripping process, reinforcing the Li ion redistribution effect. Due to these properties, Li-Cu cells with the n-NbO2-coated separator show the most outstanding cycle stability with high Coulombic efficiency (CE) over 200 cycles.

Lithium metal batteries (LMBs) have attracted wide attentions because of their high theoretical specific capacity and low electrochemical potential. However, the growth of lithium dendrites seriously affects the practical application of LMBs. Thus, the lithium‐philic carbonyl and carboxy dual‐group‐modified covalent organic framework (COF‐COOH) is designed to coat the polypropylene (PP) separator (COF‐COOH@PP separator), realizing the regulation of ion transport and uniform lithium deposition. The plentiful and negative charge sites in the COF‐COOH can suppress the diffusion of the freely movable lithium salt anion by the electrostatic interaction. Density functional theory (DFT) calculations demonstrate that the COF‐COOH possesses the function of anchoring anion and desolvation. Consequently, the Li+ transference number (0.7), ion conductivity (0.64 mS cm−1), and desolvating of Li+ are obviously improved by using the COF‐COOH@PP separator. The modified Li‐Li symmetric battery delivers stable cycle for more than 1000 h and lower voltage hysteresis (0.02 V). This dendrite‐free deposition strategy holds great promise for practical application of Li metal anodes. [ABSTRACT FROM AUTHOR]

• The Co-O-P bond is confirmed from the surface Co(PO 3) 2 by molybdenum blue analysis. • The induced P vacancy from CoP enhances the electrical conductivity of OCoP/CNT. • In-situ Raman indicates the reversible conversion of amorphous Co(PO 3) 2 accompanying the strong anchoring towards LiPSs. Electrocatalysts is maturely explored to strengthen the conversion kinetics for lithium polysulfides (LiPSs) and avoid the shuttle effect. However, the perspicuous role of surface oxidation species electrocatalysts on LiPSs conversion kinetics is still confused and needs to be uncovered. Here, we prepared progressively surface oxidized CoP/CNT (O CoP/CNT) and confirmed the formation of surface amorphous Co(PO 3) 2. The generation of surface Co(PO 3) 2 induces the phosphorous vacancy synergistically improving the catalytic conversion kinetics of O CoP/CNT functionalized separator towards LiPSs. Furthermore, the In-situ Raman spectra is adopted to disclose the key catalytic role of Co(PO 3) on O CoP/CNT. With an E/S ratio of 15 µL mg−1, the lithium sulfur (Li-S) battery with O CoP/CNT functionalized separator showcases amazing and satisfying high-rate performance, especially at 2C and 3C. This study would get across the full comprehension of the catalytic role of the surface oxidation species and guide the new approach for the metal-based electrocatalyst of Li-S battery. [ABSTRACT FROM AUTHOR]

• New insights on the reaction mechanism of Cu 2 Se with carbon-modified separator. • Altering the reaction mechanism of Cu 2 Se from bulk diffusion to surface capacitive. • The Cu 2 Se with carbon-modified separator delivers 95 mAh g −1 over 5000 cycles. • A promising strategy for the practical application of Cu 2 Se in aluminum batteries. Transition metal selenides (TMSs) become one of the most promising cathode materials for rechargeable aluminum batteries (RABs) due to the advantages of high specific capacity, low cost, and simple preparation process. However, TMSs are soluble in the acidic chloroaluminate ionic liquid electrolyte during cycling, leading to undesirable electrochemical performance. Herein, rechargeable Al-Cu 2 Se batteries are fabricated with acetylene black modified separator (AB/GF/A) showing excellent electrochemical performance with capacity retention of 95 mAh g−1 after 5000 cycles at 0.5 A g−1 and 166.1 mAh g−1 at 1.0 A g−1. By combining electrochemical tests and ex situ spectroscopy and electronic microscope characterizations, it is revealed that the dissolved Cu and Se species adsorbed on the surface of AB/GF/A still remain electroactivity, which transforms the diffusion-controlled mechanism of Cu 2 Se to surface pseudocapacitance-controlled behavior, thus suppressing the shuttle effects and boosting the reaction kinetics. The in-depth understanding of the functionalized separator in energy storage mechanism of TMSs could provide reference for further progress of RABs in the future work. Adopting carbon-modified separator in rechargeable aluminum batteries suppresses shuttle effect and alters the reaction mechanism of Cu 2 Se from bulk diffusion to surface capacitive, enabling long cycling life and fast reaction kinetics. [Display omitted] [ABSTRACT FROM AUTHOR]

The development of lithium (Li) metal batteries (LMBs) has been limited by problems, such as severe dendrite growth, drastic interfacial reactions, and large volume change. Herein, an LMB (8AP@LiB) combining agraphene oxide-poly(ethylene oxide) (PEO) functionalized polypropylene separator (8AP) with a lithium-boron (LiB) anode is designed to overcome these problems. Raman results demonstrate that the PEO chain on 8AP can influence the Li + solvation structure in the electrolyte, resulting in Li + homogeneous diffusion and Li + deposition barrier reduction. 8AP exhibits good ionic conductivity (4.9 × 10 -4 S cm -1 ), a high Li + migration number (0.88), and a significant electrolyte uptake (293%). The 3D LiB skeleton can significantly reduce the anode volume changes and local current density during the charging/discharging process. Therefore, 8AP@LiB effectively regulates the Li + flux and promotes the uniform Li deposition without dendrites. The Li||Li symmetrical cells of 8AP@LiB exhibit a high electrochemical stability of up to 1000 h at 1 mA cm -2 and 5 mAh cm -2 . Importantly, the Li||LiFePO 4 full cells of 8AP@LiB achieve an impressive 2000 cycles at 2C, while maintaining a high-capacity retention of 86%. The synergistic effect of the functionalized separator and LiB anode might provide a direction for the development of high-performance LMBs.

Since the so-called ‘shuttle effect’ is the key obstacle for the practical development of lithium-sulfur batteries, the present attempt is to make the separator less permeable for polysulfides. For this purpose, we synthesized Ni-based metal-organic framework (Ni-MOF) particles and coated them with multi-walled carbon nanotubes (MWCNTs) onto the polyethylene (PE) separator. The Ni-MOF particles on separator effectively blocked the migration of lithium polysulfides toward the anode side owing to the strong interaction between Ni-MOFs and lithium polysulfides. The highly conductive MWCNTs in the coating layer allowed reutilization of the trapped reaction intermediates during the subsequent cycles. Due to these beneficial effects of coating materials, the lithium-sulfur cell assembled with Ni-MOF/MWCNT-coated PE separator initially delivered a high discharge capacity of 1358 mAh g −1 with good cycling stability and high-rate performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A niobium oxide is employed as a separator coating material against Li metal. • The niobium oxide coated separator can redistribute the localized Li ion. • Nitridation was performed on niobium dioxide to improve the electrical conductivity. • A nitrided niobium dioxide coated separator leads to the high cycle stability in LMB. Lithium (Li) metal anodes have received intensive attention owing to its high specific capacity and low redox potential. However, chronic issues related to dendritic Li growth have hindered the pragmatic use of Li-metal batteries (LMBs). As one of feasible approaches, depositing a functional material on the separator is an efficient strategy for improving the electrochemical stability of LMBs. In this paper, we report a functionalized separator, comprising a nitrided niobium dioxide (named as n-NbO 2) and a polypropylene (PP) separator. It is identified that niobium oxide interact with metallic Li, resulting in redistributing the localized Li ion. The n-NbO 2 -coated separator with enhanced electrical conductivity promotes Li plating/stripping process, reinforcing the Li ion redistribution effect. Due to these properties, Li-Cu cells with the n-NbO 2 -coated separator show the most outstanding cycle stability with high Coulombic efficiency (CE) over 200 cycles. [ABSTRACT FROM AUTHOR]

In this work, the lightweight and scalable organic macromolecule graphitic carbon nitride (g-C3N4) with enriched polysulfide adsorption sites of pyridinic-N was introduced to achieve the effective functionalization of separator at the molecular level. This simple method overcomes the difficulty of low doping content as well as the existence of an uncontrolled form of nitrogen heteroatom in the final product. Besides the conventional pyridinic-N-Li bond formed in the vacancies of g-C3N4, the C-S bond was interestingly observed between g-C3N4 and Li2S, which endowed g-C3N4 with an inherent adsorption capacity for polysulfides. In addition, the microsized g-C3N4 provided the coating layer with good mechanical strength to guarantee its restriction function for polysulfides during long cycling. As a result, an excellent reversible capacity of 840 mA h g(-1) was retained at 0.5 C after 400 cycles for a pure sulfur electrode, much better than that of the cell with an innocent carbon-coated separator. Even at a current density of 1 C, the cell still delivered a stable capacity of 732.7 mA h g(-1) after 500 cycles. Moreover, when further increasing the sulfur loading to 5 mg cm(-2), an excellent specific capacity of 1134.7 mA h g(-1) was acquired with the stable cycle stability, ensuring a high areal capacity of 5.11 mA h cm(-2). Besides the intrinsic adsorption ability for polysulfides, g-C3N4 is nontoxic and mass produced. Therefore, a scalable separator decorated with g-C3N4 and a commercial sulfur cathode promises high energy density for the practical application of Li-S batteries.