Herein, we report the molecular engineering of anion-fluxing polymeric metal phthalocyanines (MTPs) by controlling the types of metal centers and incorporating lithiophilic linkers to achieve ultrastable Li metal batteries. Spectroscopic characterization, cryogenic transmission electron microscopy, and computational simulations demonstrate that the Co-N 4 sites of Co in the incorporated MTP (CoTP) facilitate the local accumulation and directional flux of TFSI anions, inducing the formation of uniform, dense LiF-rich solid electrolyte interphases. As a result of this interfacial chemistry, symmetric cells with CoTP@CC-Li exhibited outstanding cycling stability, exceeding 2500 h at 1 mA cm - 2 and 1 mAh cm -2 . CoTP@CC-Li||LiFePO 4 full cells operated stably for over 600 cycles under fast charge/discharge conditions, with a high-mass-loading cathode of 20 mg cm - 2 . CoTP@CC-Li||LiFePO 4 pouch cells demonstrated stable cyclability under demanding practical conditions, including a low N/P ratio of 2.5, high cathode mass loading (23.53 mg cm - 2 ), and lean electrolyte usage (5 g Ah -1 ). Furthermore, CoTP@CC-enabled anode-free full cells achieved exceptional stability over 500 cycles, even under stringent conditions (NCM811 mass loading of 20 mg cm - 2 and lean electrolyte usage of 3 g Ah -1 ). These results highlight the effectiveness of the anion-flux interfacial engineering strategy for enabling stable and reversible Li deposition under demanding conditions.

The growing demand for energy storage systems (ESS) driven by the expansion of renewable energy calls for aqueous Zn-I2 batteries that offer both safety and cost competitiveness. However, the hydrogen evolution reaction (HER) and Zn anode corrosion, combined with iodine dissolution and polyiodide shuttling at the I2 cathode, form a degradation loop through interelectrode interactions, that impairs battery lifespan and efficiency. This study proposes a dual-interface regulation strategy by introducing the multidentate chelator TPEN as an electrolyte additive. This strategy promotes the formation of Zn2+-TPEN coordination species (TCC) in the electrolyte, which reconfigures the electric double layer of Zn anode into an interfacial environment with reduced water accessibility via interfacial adsorption, suppressing HER and corrosion, and stabilizing local pH fluctuations while promoting uniform nucleation and deposition. Simultaneously, at the I2 cathode, it traps polyiodide to reduce free polyiodide concentration and directs the reaction pathway toward the interface, thereby decreasing shuttling and self-discharge while improving I2 deposition uniformity. As a result, the Zn||Zn symmetric cell operated stably for over 2000 h and achieved a Coulombic efficiency of over 96.2% and a capacity retention of 92.5% after 200 cycles under high-loading I2 (5.5 mAh cm-2) and 0.18 C conditions.

Localized high-concentration electrolytes (LHCEs) are considered as promising electrolyte candidates to resolve technical issues of metal batteries owing to their unique interfacial properties and solvation structures. Herein, we propose a self-assembly chemical strategy into the LCHEs induced by ordered nanostructure of zwitterionic co-solutes for highly efficient and ultrastable zinc (Zn) metal batteries. Through the systematic screening of six zwitterionic compounds, 3-(decyldimethylammonio)propanesulfonate salt (C10) with the decyl chain and zwitterions was determined as an optimum to construct quasi-spherical aggregates with a periodic length of 3.77 nm, as confirmed by comprehensive synchronous small-angle X-ray scattering, Guinier, pair distance distribution function, Porod, and other spectroscopic characterizations and molecular dynamic simulation. In particularly, this self-assembled structure in electrolyte environments was attributed to increasing the proportion of both contact and aggregated ion pairs for the formation of LHCEs as well as to providing fast and selective Zn2+ conducting channels and uniform solid electrolyte interfaces for facilitated charge transfer kinetics. Moreover, the preferential adsorption of the self-assembled C10 on the Zn(002) surface modulated the electrical double layer to suppress hydrogen evolution and corrosion reactions. Consequently, the Zn||Zn symmetric cells in Zn(OTf)2/C10 electrolytes showed long-term plating/stripping behaviors over 2800 h at 1 mA cm-2 and 1 mAh cm-2 as well as over 1200 h even at 5 mA cm-2 and 5 mAh cm-2 with a very high depth of discharge of 42.7%. Furthermore, the Zn||VO2/CNT full cells in Zn(OTf)2/C10 electrolytes delivered a record-high capacity of 8.10 mAh cm-2 at an ultrahigh cathode mass loading of 50 mg cm-2 after 150 cycles.

Aqueous aluminum-ion batteries face significant challenges in achieving stable plating/stripping owing to issues such as hydrogen evolution and corrosion. Although the in situ formation of Zn-Al alloys via Zn anodes and Al3+-based electrolytes enables a suitable operating potential, this approach is hindered by cycling deactivation caused by uneven deposition and side reactions. Herein, we employ an amphiphilic zwitterion (ZI-10) as an electrolyte additive to enhance the stability of Zn-Al alloy anodes. Small-angle X-ray scattering (SAXS) and sum frequency generation (SFG) spectroscopy reveal that the self-assembly of ZI-10 forms ordered aggregates, thereby constructing a dual-layered electric double layer (EDL) that excludes water from the electrode interface while facilitating reversible plating/stripping. The zwitterionic chelation further induces a polarizable Al3+ solvation shell that reduces the energy barrier for charge transfer. Ultimately, Zn-Al||Zn-Al symmetric cells achieve >2500 h of stable operation at 1 mA cm-2 and 1 mAh cm-2, outperforming the recently reported counterparts. Full cells paired with MnVO cathodes sustain stable cycling even under 10 mg cm-2 cathode loading, while Zn-Al||I2 full cells further demonstrate exceptional long-term durability. This work offers insights into the role of amphiphilic zwitterions in tailoring electrolyte nanostructure and interfacial reaction kinetics.

Hydrogel electrolytes for flexible aqueous zinc-ion batteries (ZIBs) are limited by unregulated anion mobility, which triggers concentration polarization, dendrite growth, and parasitic reactions. Herein, a high-Zn2+-transference hydrogel electrolyte (ex-PDADAM) is developed by exchanging Cl- with ClO4 - at quaternary ammonium sites within a poly(diallyldimethylammonium)-polyacrylamide co-network. This single anion-exchange step fulfills three functions simultaneously: (i) electrostatic immobilization of anions suppresses anion migration and promotes high Zn2+ transference, increasing the transference number to 0.86; (ii) multivalent ionic crosslinks between ammonium cations and perchlorate anions reinforce the network toughness to 51.25 MJ m-3; and (iii) restructuring of the hydrogen-bonding network of water within the hydrogel matrix suppresses parasitic reactions and widens the electrochemical stability window to 2.75 V. The ex-PDADAM hydrogel delivers an ionic conductivity of 8.10 mS cm-1 at 25 degrees C, enabling Zn||Zn symmetric cells to cycle stably for over 2000 h at 1 mA cm-2 (35 mV overpotential). Flexible 4 & times; 3 cm2 pouch cells paired with vanadium oxide cathodes deliver similar to 270 mAh g-1 under 0 degrees-360 degrees bending and retain 90.9% capacity after 300 cycles. This work establishes anion-exchange chemistry as a versatile strategy for high-Zn2+-transference hydrogel electrolytes toward mechanically robust flexible ZIBs.

Anode-free lithium metal batteries (AFLMB) can maximize the energy density by eliminating active materials, conductive agents and binders from the anode. However, intrinsic issues of lithium (Li) metal anodes, such as non-uniform Li growth, large volume changes and unstable solid electrolyte interphase (SEI), become much pronounced, rapidly degrading the cyclability of AFLMB. Herein, we present a superior three-dimensional (3D) AFLMB host, which takes advantage of partially decomposed polymeric copper phthalocyanines bridged by dithioether linkers (CuPPc-S) as an ultra-thin surface coating layer. By intensive material characterizations alongside in-situ thermal gravimetric analyses coupled with mass spectrometer, we demonstrate that our controlled pyrolysis results in the formation of partially pyrolyzed CuPPc-S (PP-CuPPc-S), where intrinsic redox active sites of CuPPc-S and newly formed ultra-fine Cu-S inorganic compounds co-exist. The preserved redox active sites can not only improve lithiophilicity, but also facilitate the decomposition of TFSi-, inducing abundant LiF in the SEI, while Cu-S compounds can serve dual roles as active Li nucleation sites and ionically conductive Li2S inducer in the SEI. Benefiting from these components, PP-CuPPc-S coated carbon fiber (PP-CuPPc-S@CF) can form a multifunctional SEI and induce dense Li nucleation, achieving the stable operation of 1000 cycles with a LiFePO4 cathode in AFLMB configuration.

Stereoisomerism, arising from the distinctive spatial arrangements of atoms despite identical molecular formulae, often displays different chemical reactivities. Herein, we demonstrate how geometric isomerism of multifunctional electrolyte additives affects aqueous zinc metal batteries. Inspired by natural bacteria, we compared trans-butenedioic acid (fumaric acid) and its cis-isomer (maleic acid), revealing different hydrogen bonding dynamics and solvation environments, as confirmed by femtosecond transient absorption spectroscopy and computational simulations. The trans-isomer promotes the formation of favorable interfacial structures and ion pathways, improving Zn deposition reversibility and cycling stability. As a result, Zn symmetric cells showed stable plating/stripping for over 6150 h at 1 mA cm-2 and 1 mAh cm-2 and 1500 h at 5 mA cm-2 and 5 mAh cm-2. The Zn-predeposited Cu||MnVO full cells exhibited a capacity retention exceeding 70% after 1000 cycles at 2 A g-1, ultimately achieving over 270 cycles for initially anodeless Cu||zincated MnVO cells at a high current density of 30 mA cm-2. The application of the isomerism concept on the design of new electrolyte materials and associated solvated and interphasial chemistries offers a new pathway to the next generation of batteries.

Aqueous zinc metal batteries (AZBs) have emerged as promising alternatives to lithium‐based energy storage systems owing to their low cost, intrinsic safety, and abundant elemental resources. However, their commercial viability has been severely restricted by critical challenges such as dendrite growth, chemical corrosion, hydrogen evolution reaction, poor temperature adaptability, and cathode dissolution. To address these issues, hybrid electrolyte strategies have been extensively explored, as they can stabilize the Zn metal anode, cathode, and electrode/electrolyte interface, demonstrating significant potential for AZBs. Herein, the recent advance in the design of hybrid electrolytes is comprehensively reviewed. First, the fundamental properties and the classification of hybrid electrolytes are discussed. Then, the challenges and strategies on anode, cathode, and electrolyte are systematically debated. Furthermore, critical considerations, including ionic conductivity, electrolyte stability, voltage window, and side reactions, for the rational design of hybrid electrolytes are addressed, along with the challenges in optimizing battery performance. Additionally, this review addresses bottleneck issues for practical AZBs, such as large‐scale production, cost control, reproducibility, and safety. Finally, the prospects for the advanced hybrid electrolytes are provided, guiding the development of the practical AZBs toward future energy storage technologies.

Aqueous zinc-ion batteries (AZIBs) are emerging as a highly promising alternative to lithium-ion batteries for next-generation energy storage, owing to their intrinsic safety, low cost, and environmental friendliness. In order to overcome these limitations, herein, a representative set of saccharide-based electrolyte additives is systematically screened, aiming to precisely tune the steric hindrance and molecular geometry by varying their glycosidic linkages. Cellobiose (CBS), with its unique beta-1,4-glycosidic bond, is identified as a superior additive. Theoretical and spectroscopic analyses reveal that CBS manipulates the hydrogen-bond network, enhancing low-temperature performance. Its zincophilic nature promotes adsorption, forming a robust hybrid solid electrolyte interphase that orients deposition to the Zn (002) plane and mitigates parasitic side reactions. Consequently, symmetric cells with the CBS additive achieved an exceptional lifespan exceeding 4000 h and stable operation at a high depth of discharge (46.97%). Furthermore, Zn||NH4V4O10 pouch cell delivered 89.21% of capacity retention after 400 cycles with a high cathode mass loading (7.82 g cm-2) and a low N/P ratio (2.9). This work establishes a rational design strategy using a sustainable additive to develop high-performance, wide-temperature AZIBs.

Polyoxometalate (POM) exhibits strong Br & oslash;nsted acidity, making it a promising catalyst; however, its application as an electrocatalyst is limited by a low electrical conductivity and non-uniform dispersion on the support due to bulky and insulating ligands. Here, we demonstrate molecularly dispersed polyoxometalate clusters supported on nitrogen-doped reduced graphene oxide (NG) via a polymeric ionic liquid (PIL) linker forming POM/PIL/NG for flexible zinc-air batteries (ZABs). The molecularly dispersed POM clusters achieved bifunctional and high electrocatalytic activity of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) through a chemical modification with redox-active metal (Co), enlarged redox-active surface area, and fast oxygen transport. Additionally, PIL improved the interfacial stability and ion transfer between POM and NG. Thus, POM/PIL/ NG hybrid electrocatalysts achieved the outstanding catalytic activities, including a high onset and half-wave potential of ORR (Eon = 0.84 V, E1/2 = 0.79 V) and a low OER overpotential (ti10 = 430 mV). Consequently, rechargeable ZABs with POM/PIL/NG delivered a high power density of 100.7 mW cm-2 with stable voltage profiles over 340 cycles. Furthermore, quasi solid-state ZABs confirmed the potential as flexible energy storage devices, delivering a power density of 45.0 mW cm-2 and powering various electronic devices in tandem cell configurations.

Lithium (Li) metal anodes have received significant attention owing to their high theoretical capacity and low redox potential. Herein, a 3D bucky paper-based host is demonstrated, consisting of multi-walled carbon nanotubes (MWCNT) and Ag nanoparticles, for the uniform and dense Li deposition. The as-designed Ag-embedded MWCNT bucky paper (Ag/MCBP) achieves low Li nucleation overpotentials and high coulombic efficiencies (CEs), owing to the high Li affinity of Ag nanoparticles and 3D electronically conductive, porous architecture of MWCNT. Consequently, the optimized sample of Ag/MCBP-10 delivers a high average CE of 99.31% over 150 cycles at 2 mA cm-2 and 4 mAh cm-2 in symmetric cells. The Li metal full batteries are configured pairing Li@Ag/MCBP-10 with lithium iron phosphate (LFP), lithium manganese iron phosphate (LMFP), and nickel-rich LiNi0.8Co0.1Mn0.1O2 (NCM811). The Li@Ag/MCBP-10||LFP full cells retain 95.65% of capacity after 100 cycles at 1C, while the Li@Ag/MCBP-10||LMFP full cells achieve 79.30% of capacity retention after 100 cycles at 0.5C. Moreover, the Li@Ag/MCBP-10||NCM811 full cells, with a high mass loading of NCM811 cathode (22 mg cm-2, 4.4 mAh cm-2) deliver the high specific capacity of 208.74 mAh g-1 at 0.2C rate under harsh condition of approximate to 0.9 neutron-to-proton ratio.

Commercial lithium-ion batteries (LIBs) suffer substantial performance degradation at subzero temperatures due to the increased viscosity of ethylene carbonate (EC)-based electrolytes and a high energy barrier for lithium-ion (Li+) desolvation at the graphite anode interface, posing critical challenges for applications in cold climates and extreme environments. To overcome this, a phosphonium-based ionic liquid, allyl trimethyl phosphonium bis(trifluoromethane)sulfonimide (APT), is introduced as a multifunctional electrolyte additive. APT forms a eutectic mixture with EC, effectively lowering the freezing point and viscosity while enhancing ionic conductivity at low temperatures. Furthermore, APT weakens the Li+-EC interaction, facilitating more efficient Li+ desolvation at the graphite interface, and promotes the formation of a thin, uniform, LiF-rich solid electrolyte interphase on the graphite anode, leading to the fast interfacial Li+ transfer kinetics. Pouch cells with high-mass-loading electrodes (NCM811||graphite, 4.9 mAh cm(-2)) and lean electrolyte (3 g Ah(-1)) containing 1 wt.% of APT retained 87.56% of their capacity after 100 cycles at -20 degrees C, significantly outperforming cells without the additive (64.60% retention). Therefore, this work provides a rational design strategy for multifunctional electrolyte additives that simultaneously optimize bulk transport properties and interfacial stability for reliable LIB operation under subzero conditions.

Aqueous zinc metal batteries (ZMBs) are attractive owing to their intrinsic safety and low cost. However, their practical applications are limited by dendrite growth, hydrogen evolution reactions (HERs), and corrosion. Additionally, the N/P ratio is too high to achieve a large energy density and the current rate is often restricted to <= 4 mA cm-2. Herein, we demonstrate multifunctional additives of imide derivatives for practical aqueous Zn metal full cells. By systematically comparing four imide derivatives to assess the role of relevant functional groups in the reversibility of Zn deposition, succinimide (H-SU) was chosen as a proof-of-concept additive among the molecularly engineered imide derivative additives. The H-SU additive reconstructs the solvation sheath of Zn2+ with imino groups, disrupts the hydrogen bond (HB) network of free water with carbonyl groups, and is adsorbed onto the Zn surface to adjust the inner Helmholtz plane. These combined modifications of solvated and interfacial structures by the multifunctional H-SU additive led to alleviation of the HER and enabled uniform Zn deposition. Consequently, the H-SU additive enabled Zn & Vert;Zn symmetric cells to exhibit long term stability over 2700 h at 1 mA cm-2 and 1 mA h cm-2 and even to achieve a record of 21 000 cycles (or 700 h) at an extremely high current density of 60 mA cm-2. Furthermore, the H-SU additive optimized the battery performance of full cells integrating Zn anodes with three types of cathodes, including polyaniline (PANI), manganese vanadate, and molybdenum oxide@titanium dioxide. Particularly, the Zn & Vert;PANI full cells with a low N/P ratio of 2.2 and an ultrahigh loading of 60 mg cm-2 delivered a high areal capacity of 4.2 mA h cm-2 after 100 cycles. Therefore, this work provides insights into the molecular engineering design of multifunctional imide derivative additives and offers technical breakthroughs for practical Zn metal full cells. The molecularly engineered multifunctional additive of H-SU, which effectively modulates both solvated and interfacial structures, was chosen from a family of imide derivatives for practical aqueous Zn metal full cells.

AbstractThe polymeric gel electrolytes are attractive owing to their higher ionic conductivities than those of dry polymer electrolytes and lowered water activity for enlarged potential window. However, the ionic conductivity and mechanical strength of the Na‐ion conducting polymeric gel electrolytes are limited by below 20 mS cm−1 and 2.2 MPa. Herein, we demonstrate Na‐ion conducting and flexible polymeric hydrogel electrolytes of the chemically coupled poly(diallyldimethylammonium chloride)‐dextrin‐N,N′‐methylene‐bis‐acrylamide film immersed in NaClO4 solution (ex‐DDA‐Dex + NaClO4) for flexible sodium‐ion hybrid capacitors (f‐NIHC). In particular, the anion exchange reaction and synergistic interaction of ex‐DDA‐Dex with the optimum ClO4− enable to greatly improve the ionic conductivity up to 27.63 mS cm−1 at 25°C and electrochemical stability window up to 2.6 V, whereas the double networking structure leads to achieve both the mechanical strength (7.48 MPa) and softness of hydrogel electrolytes. Therefore, the f‐NIHCs with the ex‐DDA‐Dex + NaClO4 achieved high specific and high‐rate capacities of 192.04 F g−1 at 500 mA g−1 and 116.06 F g−1 at 10 000 mA g−1, respectively, delivering a large energy density of 120.03 W h kg−1 at 906 W kg−1 and long cyclability of 70% over 500 cycles as well as demonstrating functional operation under mechanical stresses.

Two-dimensional (2D) materials display a unique set of physical/chemical properties and are considered potential building blocks for the manufacturing of microstructured materials for a number of applications. Prominent applications range from advanced electronics to miniaturized electrochemical energy storage devices (EESDs). Herein, we present a comprehensive and critical review of the recent developments in design and microfabrication of 2D-driven microscale electrodes for three-dimensional (3D)-printed micro-supercapacitors and micro-batteries. Firstly, we systematically discuss the advantages and disadvantages associated with various microfabrication techniques such as stereolithography, fused deposition modeling, inkjet printing, and direct ink writing. Next, key parameters disclosing the relationship between the characteristics of 2D-based materials and extrusion-driven 3D printing process for the development of versatile and sustainable EESDs are highlighted. 2D materials utilized for the construction of microelectrodes for supercapacitors (e.g., electric double layer capacitors (EDLCs), pseudocapacitors, and hybrid capacitors) and batteries (e.g., Li-based systems and next-generation systems, e.g., sodium-ion batteries and zinc-ion batteries) along with their prominent electrochemical contributions in relation to obtained 3D-printed architectures are discussed in detail. To promote the development of 2D materials-driven high-performance microscale EESDs, the relevant challenges and future research opportunities are also addressed.

Metal phthalocyanine (Pc) complexes are considered to be promising functional organic materials owing to their tunable properties and unique π‐electron structure. Despite these advantages, the application of polymeric metal Pc into lithium–sulfur (LiS) batteries has yet to be explored. Herein, this work demonstrates a molecular design of multifunctional polymeric cobalt Pc with triethylene glycol linkers (TCP) that provide a redox mediating capability for the Co ion in the center of the Pc, a strong polar interaction of N atoms with Li, and the lithiophilic sites of crown ether mimicking linkers for highly efficient LiS batteries. As verified by electrochemical and theoretical analyses, the cooperative redox mediating and lithiophilic effects of TCP coated onto multiwalled carbon nanotube (TCP/MC) are attributed to the facilitated conversion reaction kinetics of S cathodes for the high utilization efficiency of S and the inhibition of polysulfide shuttling. Consequently, the S@TCP/MC delivers high discharge capacity of 1392.8 mA h g −1 and high‐rate capacity of 667.9 mA h g −1 at 5.0 C. Moreover, this cathode achieves a high capacity retention of 81.5% over 200 cycles, along with a high areal capacity of 6.83 mA h cm −2 at 0.2 C with a high S loading of 6.6 mg cm −2 .

Herein, we demonstrate an inorganic-organic double network gel electrolyte consisting of a silica particle network and a poly-2-hydroxyethyl methacrylate network in which 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquids are confined. The as-synthesized double network ionogel electrolytes exhibited high ion conductivity of 3.8 to 12.8 mS cm-1 over a wide temperature range of 30 to 150 °C and mechanical integrity with a maximum toughness of 1.8 MJ m-3 at 30 °C. These remarkable properties of the ionogel were associated with the formation of an optimal physical network of the silica nanoparticles in the colloidal dispersion. Accordingly, a flexible supercapacitor using ionogel electrolytes and reduced graphene oxide electrodes delivered energy and power densities of 48 Wh kg-1 and 4 kW kg-1, respectively, even at a high temperature of 120 °C, demonstrating excellent long-term stability that retains 93% of the initial capacitance even over 10,000 charge/discharge cycles at 120 °C.

Hydrogel electrolytes, where water solvents and salts are confined in the porous networks of polymeric or inorganic solids, are attractive because they can resolve technical challenges of liquid electrolytes such as leakage, water decomposition, and mechanical instability. Herein, we demonstrate polyacrylic acid tethered onto the surface of vinyl functionalized silica nanoparticles (PAA-VSNP) hydrogel electrolytes through a sol-gel and radical polymerization process. The synthesis chemistry, the associated chemical structure, and the morphology of PAA-VSNP hydrogel electrolytes were comprehensively characterized analyzing FTIR, XPS and 13C and 29Si solid-state MAS NMR spectroscopies. The resulting PAA-VSNP hydrogel electrolytes were mechanically stable as verified by the stretchability up to 1122.75% of original length as well as ionically conductive as demonstrated by higher ionic conductivity of 20.23 mS cm−1 and lower activation energy of 0.106 eV than those of PVA counterparts. Integrating this PAA-VSNP hydrogel electrolytes with activated carbon and Na3V2(PO4)3/carbon composite and, flexible sodium ion hybrid supercapacitors (AC//PAA-VSNP //NVP@C SHSC SHSC) full cells could be fabricated. The as-fabricated AC//PAA-VSNP//NVP@C SHSC achieved a long-term cyclability over 4000 cycles and flexibility, delivering the larger energy and power densities 86.95 W h kg−1 and 19.94 kW kg−1 than those of AC//PVA//NVP@C and other works using hydrogel electrolytes.

Lithium-sulfur (Li-S) batteries are receiving increasing attention as one of the potential next-generation batteries, owing to their high energy densities and low cost. However, practical Li-S batteries with high energy densities are extremely hindered by the sulfur loss, low Coulombic efficiency, and short cycling life originating from the polysulfide (LiPS) shuttle. In this study, two-dimensional (2D) ZnCo2O4 microsheets fabricated by a facile hydrothermal process are employed to modify the separator, for improving the electrochemical performances of Li-S cells. The resulting 2D ZnCo2O4-coated separator features a coating thickness of approximately 10 mu m, high ionic conductivity of 1.8 mS/cm, and low mass loading of 0.2 mg/cm(2). This 2D ZnCo2O4-coated separator effectively inhibits LiPS shuttle by a strong chemical interaction with LiPS as well as promotes the redox kinetics by ZnCO2O4-coated layers, as determined by X-ray photoelectron spectroscopy analysis, self-discharge, time-dependent permeation test, Li symmetric cell test, and Li2S nucleation analyses. Consequently, the Li-S batteries based on the 2D ZnCo2O4-coated separator exhibit a high initial discharge capacity of 1292.2 mAh/g at 0.1 C. Moreover, they exhibit excellent long cycle stability at 1 and 2 C with capacity retention of 84% and 86% even after 800 cycles, corresponding to a capacity fading rate of 0.020% and 0.016% per cycle, respectively. Effectively, these Li-S cells with a high sulfur loading at 5.3 mg/cm(2) and low electrolyte concentration of 9 mu L/mg deliver a high discharge capacity of 4.99 mAh/cm(2) after 200 cycles at 0.1 C. (C) 2020 Published by ELSEVIER B.V. and Science Press on behalf of Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences.