Unveiling the In Situ Evolution of Li2O-Rich Solid Electrolyte Interface on CoOx Embedded Carbon Fibers as Li Anode Host.

Modification of three-dimensional (3D) carbon hosts with metal oxides has been considered as advantageous for the formation of Li2O-rich solid electrolyte interface (SEI), which can show fast Li+ diffusion, and meanwhile alleviate dendrite problems caused by fragility and nonuniformity of native SEIs. However, the lack of convincing experimental evidence has made it difficult to unveil the true origin of oxygen in Li2O-rich SEIs until now. Herein, CoOx embedded carbon nanofibers (CNF-CoOx) are successfully prepared as high-performance Li anode hosts. By employing 18O isotope labeling, the role of CoOx during SEI evolution is elucidated, revealing that CoOx contributes significantly to Li2O formation by delivering oxygen. Benefiting from the rich Li2O content, the as-formed SEIs greatly improve the Li+ migration kinetics, and therefore, the CNF-CoOx@Li anode can exhibit excellent cycling stability in half, symmetrical, and full cells.

Capacity Degradation of Zero-Excess All-Solid-State Li Metal Batteries Using a Poly(ethylene oxide) Based Solid Electrolyte.

Solid-state polymer electrolytes (SPEs), such as poly(ethylene oxide) (PEO), have good flexibility when compared to ceramic-type solid electrolytes. Therefore, it could be an ideal solid electrolyte for zero-excess all-solid-state Li metal battery (ZESSLB), also known as anode-free all-solid-state Li battery, development by offering better contact to the Cu current collector. However, the low Coulombic efficiencies observed from polymer type solid-state Li batteries (SSLBs) raise the concern that PEO may consume the limited amount of Li in ZESSLB to fail the system. Here, we designed ZESSLBs by using all-ceramic half-cells and an extra PEO electrolyte interlayer to study the reactivity between PEO and freshly deposited Li under a real battery operating conduction. By shuttling active Li back from the anode to the cathode, the PEO SPEs can be separated from the ZESSLBs for experimental studies without the influence from cathode materials or possible contamination from the usage of Li foil as the anode. Electrochemical cycling of ZESSLBs shows that the capacities of ZESSLBs with solvent-free and solvent-casted PEO SPEs significantly degraded compared to the ones with Li metal as the anode for the all-solid-state Li batteries. The fast capacity degradation of ZESSLBs using different types of PEO SPEs is evidenced to be associated with Li reacting with PEO, residual solvent, and water in PEO and dead Li formation upon the presence or absence of residual solvent. The results suggest that avoiding direct contact between the PEO electrolyte and deposited lithium is necessary when there is only a limited amount of Li available in ZESSLBs.

Dual-Component Interlayer Enables Uniform Lithium Deposition and Dendrite Suppression for Solid-State Batteries.

ß-Lithium thiophosphate (LPS) exhibits high Li+ conductivity and has been identified as a promising ceramic electrolyte for safe and high-energy-density all-solid-state batteries. Integrating LPS into solid-state lithium (Li) batteries would enable the use of a Li electrode with the highest deliverable capacity. However, LPS-based batteries operate at a limited current density before short-circuiting, posing a major challenge for the development of application-relevant batteries. In this work, we designed a dual-component interfacial protective layer called LiSn-LiN that forms in situ between the Li electrode and LPS electrolyte. The LiSn component, Li22Sn5, exhibits enhanced Li diffusivity compared with the metallic lithium and facilitates a more uniform lithium deposition across the electrode surface, thus eliminating Li dendrite formation. Meanwhile, the LiN component, Li3N, shows enhanced mechanical stiffness compared with LPS and functions to suppress dendrite penetration. This chemically robust LiSn-LiN interlayer provides a more than doubled deliverable critical current density compared to systems without interfacial protection. Through combined XPS and XAFS analyses, we determined the local structure and the formation kinetics of the key functional Li22Sn5 phase formed via the electrochemical reduction of a Sn3N4 precursor. This work demonstrates an example of the structural-specific design of a protective interlayer with a desired function - dendrite suppression. The structure of a functional protective layer for a given solid-state battery should be tailored based on the given battery configuration and its unique interfacial chemistry.

An Amino Acid-Enabled Separator for Effective Stabilization of Li Anodes.

Fundamentally suppressing Li dendrite growth is known to be critical for realizing the potential high energy density for Li-metal batteries (LMBs). Inspired by the ionic transport function of proteins, we previously discovered that utilizing natural proteins was able to stabilize the Li anode but have not demonstrated how a specific amino acid of the protein enabled the function. In this study, we decorate the separator with Leucine (Leu) amino acid assisted by poly(acrylic acid) (PAA) for effectively stabilizing the Li-metal anode, so as to dramatically improve the cycling performance of LMBs. The decorated separator improves electrolyte wettability and effectively suppresses Li dendrite growth. As a result, the amino acid-enabled separator prolongs the cycle life of the symmetrical Li|Li cells, exhibits higher Coulombic efficiency in the Li|Cu cells, and improves the cycling performance in LMBs with the LiFePO4 cathode. This work is an initial study on applying a specific amino acid of proteins to enhance the performance of batteries, providing a new strategy on guiding Li+ deposition, and laying an important foundation for functional separator design of high-energy-density batteries.

Halogenated Functional Electrolyte Additive for Li-CO2 Batteries.

In recent years, functional electrolyte additives have been widely studied during the CO2 evolution reaction (CO2ER) and CO2 reduction reaction (CO2RR) processes for Li-CO2 batteries. Owing to different concerns, functions of these additives are also multiple and limited. In this work, the multiple impacts of functional electrolyte additives for Li-CO2 batteries are discussed. N-phenylpyrrolidine (PPD) and 1-(3-bromophenyl) pyrrole (Br-PPD) are investigated as additives successively. First, the corresponding charging potential during the CO2ER process can be reduced to 3.65 V with PPD; then the Li||Li symmetric cells with Br-PPD possess a superior long-term cycling of 800 h benefited from a stable solid electrolyte interphase (SEI) on the surface of a Li metal by using a Li anode protected with bromine functional groups. In Br-PPD-based Li-CO2 cells, the charging potential can be maintained at 3.70 V for 120 cycles even with a Super P cathode. In this work, the relationship between the structural properties of organic molecules and their electrochemical applications is discussed and investigated. This is essential for the targeted design and preparation of additives in rechargeable batteries.

Recent Progress on Natural Clay Minerals for Lithium-Sulfur Batteries.

Li-S batteries with high energy density have the potential to become a viable alternative to Li-ion batteries. However, Li-S batteries still face several challenges, including the shuttle effect, low conversion kinetics, and Li dendrite growth. Natural clay minerals with porous structures, abundant Lewis-acid sites, high mechanical modulus, and versatile structural regulation show great potential for improving the performance of Li-S batteries. However, so far, relevant reviews focusing on the applications of natural clay minerals in Li-S batteries are still missing. To fill the gap, this review first presents an overview of the crystal structures of several natural clay minerals, including 1D (halloysites, attapulgites, and sepiolite), 2D (montmorillonite and vermiculite), and 3D (diatomite) structures, providing a theoretical basis for the application of natural clay minerals in Li-S batteries. Subsequently, research advancements in the natural clay-based energy materials in Li-S batteries have been comprehensively reviewed. Finally, the perspectives concerning the development of natural clay minerals and their applications in Li-S batteries are provided. We hope this review can provide timely and comprehensive information on the correlation between the structure and function of natural clay minerals in Li-S batteries and offer guidance for material selection and structure optimization of natural clay-based energy materials.

Dual-Functional Lithiophilic/Sulfiphilic Binary-Metal Selenide Quantum Dots Toward High-Performance Li-S Full Batteries.

The commercial viability of lithium-sulfur batteries is still challenged by the notorious lithium polysulfides (LiPSs) shuttle effect on the sulfur cathode and uncontrollable Li dendrites growth on the Li anode. Herein, a bi-service host with Co-Fe binary-metal selenide quantum dots embedded in three-dimensional inverse opal structured nitrogen-doped carbon skeleton (3DIO FCSe-QDs@NC) is elaborately designed for both sulfur cathode and Li metal anode. The highly dispersed FCSe-QDs with superb adsorptive-catalytic properties can effectively immobilize the soluble LiPSs and improve diffusion-conversion kinetics to mitigate the polysulfide-shutting behaviors. Simultaneously, the 3D-ordered porous networks integrated with abundant lithophilic sites can accomplish uniform Li deposition and homogeneous Li-ion flux for suppressing the growth of dendrites. Taking advantage of these merits, the assembled Li-S full batteries with 3DIO FCSe-QDs@NC host exhibit excellent rate performance and stable cycling ability (a low decay rate of 0.014% over 2,000 cycles at 2C). Remarkably, a promising areal capacity of 8.41 mAh cm-2 can be achieved at the sulfur loading up to 8.50 mg cm-2 with an ultra-low electrolyte/sulfur ratio of 4.1 µL mg-1. This work paves the bi-serve host design from systematic experimental and theoretical analysis, which provides a viable avenue to solve the challenges of both sulfur and Li electrodes for practical Li-S full batteries.

Hexachloro-1,3-butadiene as a Functional Additive for Constructing an Efficient Solid Electrolyte Interface Layer for Long-Life Stable Li Anodes.

Lithium (Li) metal is considered as one of the attractive anodes for next-generation high-energy-density batteries due to its ultrahigh theoretical specific capacity and low potential. However, many great challenges including uncontrolled dendrite growth and undesired side reactions during repeated cycling still seriously hinder its practical application in Li metal secondary batteries. Herein, we report the hexachloro-1,3-butadiene (HCBD) molecule as a functional additive to stabilize the Li anode by forming a stable solid electrolyte interface (SEI) layer with high Li ion conductivity via in situ surface and electrochemical reactions. Density functional theory calculations demonstrate that HCBD can preferentially react with the Li anode, which generates an ionic conducting species (LiCl) into an SEI layer. The LiCl-rich SEI layer effectively regulates Li+ deposition/stripping kinetics and then induces uniform nucleation of Li+ and reduces the side reactions between the Li anode and electrolyte. With an optimal amount of HCBD in an ether-based electrolyte, an excellent cycling lifespan (7000 h) was achieved with a low hysteresis voltage of ∼10 mV at 1.0 mA cm-2 in a Li||Li symmetrical cell. Furthermore, the LiFePO4-based cell with the additive-functionalized Li anode displays obviously improved cycling stability (with a high specific capacity of 141.1 mAh g-1 after 350 cycles at 1 C).

In Situ Constructing a Stable Solid Electrolyte Interface by Multifunctional Electrolyte Additive to Stabilize Lithium Metal Anodes for Li-S Batteries.

Lithium (Li) metal is considered to be the most promising anode due to the ultrahigh capacity and extremely low electrochemical potential. The tricky thing is that the growth of dendritic Li brings huge safety hazards to Li metal batteries. Herein, we demonstrate cerium nitrate as a multifunctional electrolyte additive to form a stable solid electrolyte interface on the metallic Li anode surface for durable Li-S batteries. The presence of Ce3+ helps to modulate the electroplating/stripping of Li and inhibits the growth of dendritic Li. An excellent cycle life exceeding 1400 h at the current density of 1 mA cm-2 can be realized in symmetric Li||Li cells. In addition, the in situ formed robust solid-electrolyte interface (SEI) layer containing cerium sulfide on the Li anode surface conduces to weaken the reducibility of Li and regulate the electrochemical dissolution/deposition reaction on the Li anode. Surprisingly, by virtue of cerium nitrate additive with a low concentration of 0.03 M, the Li-S batteries can afford a capacity of 553 mA h g-1 at 5 C and a long cycle life at 1 C with a high capacity retention of 70.4%. Therefore, this study provides a novel idea to realize a uniform and dendrite-free Li anode for practical Li-S batteries.

Facile, Atom-Economic, Chemical Thinning Strategy for Ultrathin Lithium Foils.

Metallic lithium is considered as the ultimate anode material for lithium-based batteries due to its highest energy density. However, as an anode, commercial Li metal foils are too thick, with a large amount of trouble to balance its exorbitant areal capacity with common cathodes in full cells. Here, a new chemical thinning strategy is proposed via a simple surface dissolving reaction between lithium and naphthalene, which enables scalable, continuous, and roll-to-roll preparation of ultrathin Li foil. A Li foil less than 15 µm with a clean surface can be successfully obtained within 20 min. The thinning rate and thickness of the lithium foil can be easily adjusted by changing the concentration, temperature, and operation mode. The produced Li-Naph solution after thinning can also be used as a multifunctional reagent of great value, and the Li ions in the final waste solution can be further extracted in the form of Li2CO3, showing superior lithium atom economy of our strategy.

Double-Protected Layers with Solid-Liquid Hybrid Electrolytes for Long-Cycle-Life Lithium Batteries.

Lithium-ion batteries (LIBs) with liquid electrolytes (LEs) have problems such as electrolyte leakage, low safety profiles, and low energy density, which limit their further development. However, LIBs with solid electrolytes are safer with better energy and high-temperature performance. Thus, solid electrolyte system batteries have attracted widespread attention. However, due to the inherent rigidity of the LATP solid electrolyte, there is a high interface impedance at the LATP/electrode. In addition, the Ti element in LATP easily reacts with the Li metal. Here, we dripped an LE at the LATP/electrode interface (solid-liquid hybrid electrolytes) to reduce its interface impedance. A composite polymer electrolyte (CPE) protective film (containing PVDF, SN, and LiTFSI) was then cured in situ at the LATP/Li interface to avoid side reactions of LATP. The discharge specific capacity of the LiFePO4/LATP-12% LE-CPE/Li system is up to 150 mAh g-1, and the capacity retention rate is still 96% after 250 cycles. In addition, the NCM622/PVDF-LATP-12% LE/Li system has an initial reversible capacity of 170 mAh g-1. This study reports an approach that can protect solid electrolytes from lithium metal instability.

Construction of a High-Stability and Low-Nucleation-Barrier Cu3Sn Alloy Layer on Carbon Paper for Dendrite-Free Li Metal Deposition.

The construction of three-dimensional lithiophilic hosts is one of the most effective approaches for achieving the uniform nucleation and alleviating the volume changes of the Li metal. Unfortunately, some lithiophilic materials suffer from severe mechanical degradation resulting from the large volume expansion during lithiation, which causes a heterogeneous Li deposition. Herein, a low-nucleation-barrier Cu3Sn alloy layer on a carbon paper (Cu3Sn/CP) is constructed by a facile co-electrodeposition method for the Li anode framework. Density functional theory calculations show that the Cu3Sn alloy has a higher binding energy (-2.31 eV) than pure Sn (-1.97 eV) due to the electron-deficient state of Sn in the alloy phase, which enables the lithiophilic Sn to have increased affinity for Li. Additionally, the uniformly distributed Cu particles can evenly disperse the electric field on the surface of the carbon fiber and act as a "metal barrier" to inhibit the volume expansion of the Sn particles during lithiation, thereby enhancing the electrochemical stability of the alloy modification layer. As a result, the Cu3Sn/CP anode framework exhibits an exceptionally low nucleation overpotential (∼10 mV), a high and steady Coulombic efficiency (>98.5% for more than 200 cycles), and a long lifespan up to 1150 h. The full cells with LiFePO4 as a cathode show favorable cycling performance at 1 C with a capacity retention rate of 95.2%. The construction of the Cu3Sn alloy layer in this work sheds light on the design of a high-stability lithiophilic host for the dendrite-free Li metal anode.

Two Birds with One Stone: Interfacial Engineering of Multifunctional Janus Separator for Lithium-Sulfur Batteries.

Li-dendrite growth and unsatisfactory sulfur cathode performance are two core problems that restrict the practical applications of lithium-sulfur batteries (LSBs). Here, an all-in-one design concept for a Janus separator, enabled by the interfacial engineering strategy, is proposed to improve the performance of LSBs. At the interface of the anode/separator, the thin functionalized composite layer contains high-elastic-modulus and high-thermal-conductivity boron nitride nanosheets and oxygen-group-grafted cellulose nanofibers (BNNs@CNFs), by which the formation of "hot spots" can be effectively avoid, the Li-ion flux homogenized, and dendrite growth suppressed. Meanwhile, at the interface between the separator and the cathode, the homogenously exposed single-atom Ru on the surface of reduced graphene oxide (rGO@Ru SAs) can "trap" polysulfides and reduce the activation energy to boost their conversion kinetics. Consequently, the LSBs show a high capacity of 460 mAh g-1 at 5C and ultrastable cycling performance with an ultralow capacity decay rate of 0.046% per cycle over 800 cycles. To further demonstrate the practical prospect of the Janus separator, a lithium-sulfur pouch cell using the Janus separator delivers a cell-level energy density of 310.2 Wh kg-1 . This study provides a promising strategy to simultaneously tackle the challenges facing the Li anode and the sulfur cathode in LSBs.

Effect of Organic Electrolyte on the Performance of Solid Electrolyte for Solid-Liquid Hybrid Lithium Batteries.

The interface problem caused by the contact between the electrodes and the solid electrolyte was the main factor hindering the development of solid-state batteries. To enhance the electrode|solid electrolyte interface property, we designed a hybrid electrolyte, the combination of x vol % Li1.3Al0.3Ti1.7(PO4)3 (LATP) inorganic solid electrolyte and 1 - x vol % liquid organic electrolyte (LE). In this work, the 1 - x vol % LE was dropped between the electrode and the solid electrolyte, and it is found that the electrochemical performance of the LiFePO4|Li solid-liquid hybrid battery is significantly improved. At the current density of 0.1 and 0.5 C, the LATP with 15% liquid organic electrolyte could deliver a specific capacity of 160.5 and 124.3 mAh g-1, respectively; moreover, the specific discharge capacity remained as high as 111 mAh g-1 at 0.5 C after 100 cycles, indicating that the larger interface impedance was eliminated. The LE may have three functions: (1) forming a solid-liquid electrolyte interphase on the surface of the LATP particles to prevent further reduction of LATP, (2) wetting the electrode and solid electrolyte to reduce the interface resistance, and (3) improving interfacial Li-ion transport.

High-Capacity, Dendrite-Free, and Ultrahigh-Rate Lithium-Metal Anodes Based on Monodisperse N-Doped Hollow Carbon Nanospheres.

To unlock the great potential of lithium metal anodes for high-performance batteries, a number of critical challenges must be addressed. The uncontrolled dendrite growth and volume changes during cycling (especially, at high rates) will lead to short lifespan, low Coulombic efficiency (CE), and security risks of the batteries. Here it is reported that Li metal anodes, employing the monodisperse, lithiophilic, robust, and large-cavity N-doped hollow carbon nanospheres (NHCNSs) as the host, show remarkable performances-high areal capacity (10 mAh cm-2), high CE (up to 99.25% over 500 cycles), complete suppression of dendrite growth, dense packing of Li anode, and an extremely smooth electrode surface during repeated Li plating/stripping. In symmetric cells, a highly stable voltage hysteresis over a long cycling life >1200 h is achieved, and a low and stable voltage hysteresis can be realized even at an ultrahigh current density of 64 mA cm-2. Furthermore, the NHCNSs-based anodes, when paired with a LiFePO4 (LFP) cathode in full cells, give rise to highly improved rate capability (104 mAh g-1 at 10 C) and cycling stability (91.4% capacity retention for 200 cycles), enabling a promising candidate for the next-generation high energy/power density batteries.

High-Performance Three-Dimensional Li Anode Scaffold Enabled by Homogeneous Zn Nanoclusters.

The large-scale implementation of lithium metal batteries (LMBs) has long been plagued by the uncontrollable Li deposition triggered safety issues. Herein, a lithiophilic three-dimensional Li anode scaffold, which is prepared by molten Li infusion aided by confined growth of low-cost Zn clusters, is rationally constructed for high-performance LMBs. Owing to the synergy of the carbon host and the effective regulation from the Zn nanoclusters, the large volumetric change of Li metal is well mitigated and shows a smooth and dendrite-free behavior. The Li anode scaffold can deliver much improved Coulombic efficiency, superior rate performance, and long cycle lifespan with much lower voltage polarization. Furthermore, the half cells of Li anode scaffold paired with LiFePO4 /LiCoO2 /sulfur can achieve a higher specific capacity and longer stable cycling life than those with conventional Li foil. The Li|LFP cells can achieve a stable cycling over 250 cycles at 1C with a higher capacity retention of ≈90.8%, and a higher initial discharge capacity of 924.6 mAh g-1 with a high capacity retention over 300 cycles can also be obtained in Li|S cells at 1C. This work demonstrates a cost-effective and scalable strategy for stable Li metal anode toward next-generation and high-performance LMBs.

Toward High-Performance Li Metal Anode via Difunctional Protecting Layer.

Li-metal batteries are the preferred candidates for the next-generation energy storage, due to the lowest electrode potential and high capacity of Li anode. However, the dangerous Li dendrites and serious interface reaction hinder its practical application. In this work, we construct a difunctional protecting layer on the surface of the Li anode (the AgNO3-modified Li anode, AMLA) for Li-S batteries. This stable protecting layer can hinder the corrosion reaction with intermediate polysulfides (Li2Sx, 4 ≤ x ≤ 8) and suppress the Li dendrites by regulating Li metal nucleation and depositing Li under the layer uniformly. The AMLA can cycle more than 50 h at 5 mA cm-2 with the steady overpotential of lower than 0.2 V and show high capacity of 666.7 mAh g-1 even after 500 cycles at 0.8375 mA cm-2 in Li-S cell. This work makes great contribution to the protection of the Li anode and further promotes the practical application.

High Current Enabled Stable Lithium Anode for Ultralong Cycling Life of Lithium-Oxygen Batteries.

Rechargeable lithium-oxygen (Li-O2) batteries (LOBs) with extremely high theoretical energy density have been regarded as a promising next-generation energy storage technology. However, the limited cycle life, undesirable corrosion, and safety hazards are seriously limiting the practical application of the lithium metal anode in LOBs. Here, we demonstrate a rational design of the Li-Al alloy (LiAlx) anode that successfully achieves ultralong cycling life of LOBs with stable Li cycling. Through in situ high-current pretreatment technology, Al atoms accumulates, and a stable Al2O3-containing solid electrolyte interphase protective film formed on the LiAlx anode surface to suppress side reactions and O2 crossover. The cycling life of LOB with the protected LiAlx anode increases to 667 cycles under a fixed capacity of 1000 mA h g-1, as compared to 17 cycles without pretreatment. We believe that this in situ high-current pretreatment strategy presents a new vision to protect the lithium-containing alloy anodes, such as Li-Al, Li-Mg, Li-Sn, and Li-In alloys for stable and safe lithium metal batteries (Li-O2 and Li-S batteries).

Refining Interfaces between Electrolyte and Both Electrodes with Carbon Nanotube Paper for High-Loading Lithium-Sulfur Batteries.

Lithium sulfur (Li-S) batteries are appealing energy storage technologies because of their high theoretical energy density and low cost. However, Li-S batteries suffer from poor practical energy density due to serious polysulfide dissolution and shuttle, as well as lithium anode corrosion. Herein, we provide a dual-protection strategy for the high-energy-density Li-S cell by inserting two nanotube paper (CNTp) interlayers on both electrodes. The CNTp interlayers can provide stable interfaces for both the cathode and anode, facilitating the formation of uniform charge transfer and ion flue. As a result, the Li-S cell exhibits stable cycling performance and great rate ability up to a high rate of 5 C (5 C = 25 mA cm-2). Even at an ultrahigh sulfur load of 12.1 mg cm-2, a high areal capacity of 12.6 mAh cm-2 is still achieved, which can remain at 11.1 mAh cm-2 after 30 cycles (corresponding to 917 mAh g-1). The refined interfaces between the electrolyte and both electrodes are further confirmed by the micro-zone current distribution and COMSOL simulation. Our approach provides an effective and universal strategy to improve the electrochemical stability of the Li-S cell at high sulfur load, opening a new platform for designing advanced metal cell systems.

Bioinspired Polysulfiphobic Artificial Interphase Layer on Lithium Metal Anodes for Lithium Sulfur Batteries.

The application of Li-S batteries suffers from many issues, polysulfide dissolution in particular. The fresh Li metal reacts with polysulfide continuously, which aggravates irregular Li plating/stripping behavior and decomposition of organic electrolyte resulting in short cycle life and low Coulombic efficiency. Nature has provided a lot of inspiration for human to realize structural construction and functional integration, as it does to battery design. In this report, learning from the hydrophobic property of natural species, a scaly polysulfiphobic artificial interphase layer are constructed on lithium metal anodes that can repel LiPS through the functional decylphosphonate groups that are proved by in operando XPS with Ar ion sputtering. Moreover, the obtained artificial interphase layer keeps dendrite-free morphology and restrains side reactions during cycling effectively. In situ XRD measurements are employed to demonstrate the inhibiting effect for decomposition of organic electrolyte. The as-obtained LDP-Li anodes exhibit outstanding electrochemical performance with the specific capacity of ∼1000 mAh g-1 corresponding to Coulombic efficiency of nearly 99%, which shows great promise for the application of Li-S batteries.