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Abstract Lithium–sulfur (Li–S) batteries promise high‐energy‐density potential to exceed the commercialized lithium‐ion batteries but suffer from limited cycling lifespan due to the side reactions between lithium polysulfides (LiPSs) and Li metal anodes. Herein, a three‐way electrolyte with ternary solvents is proposed to enable high‐energy‐density and long‐cycling Li–S pouch cells. Concretely, ternary solvents composed of 1,2‐dimethoxyethane, di‐isopropyl sulfide, and 1,3,5‐trioxane are employed to guarantee smooth cathode kinetics, inhibit the parasitic reactions, and construct a robust solid electrolyte interphase, respectively. The cycling lifespan of Li–S coin cells with 50 µm Li anodes and 4.0 mg cm−2 sulfur cathodes is prolonged from 88 to 222 cycles using the three‐way electrolyte. Nano‐heterogeneous solvation structure of LiPSs and organic‐rich solid electrolyte interphase are identified to improve the cycling stability of Li metal anodes. Consequently, a 3.0 Ah‐level Li–S pouch cell with the three‐way electrolyte realizes a high energy density of 405 Wh kg−1 and undergoes 27 cycles. This work affords a three‐way electrolyte recipe for suppressing the side reactions of LiPSs and inspires rational electrolyte design for practical high‐energy‐density and long‐cycling Li–S batteries.

Lithium–sulfur (Li–S) batteries promise ultrahigh theoretical energy density and attract great attention as next‐generation energy storage devices. However, the sluggish sulfur redox kinetics severely restricts the practical performances of Li–S batteries. Introducing electrocatalysts can accelerate the sulfur redox kinetics and enhance the discharge capacity and rate performances, where advanced electrocatalysts are required for better performance promotion. Herein, a Fe–Co‐based dual‐atom catalyst (DAC) is adopted to accelerate the sulfur redox kinetics and construct high‐performance Li–S batteries. The unique structure of the dual‐atom site allows synergistic effect between the adjacent metal atoms, thus enhancing the interactions with lithium polysulfides and promoting the sulfur redox kinetics over the single‐atom counterparts. As a result, Li–S batteries with DAC afford a high discharge capacity of 1034.6 mAh g−1 at 0.1 C and excellent rate performances of 728.0 mAh g−1 at 4.0 C. The introduction of DAC demonstrates the promising potential of applying advanced materials for constructing high‐performance Li–S batteries.

Lithium–sulfur (Li–S) batteries are considered as one of the most promising next-generation energy storage devices because of their ultrahigh theoretical energy density beyond lithium-ion batteries. The cycling stability of Li metal anode largely determines the prospect of practical applications of Li–S batteries. This review systematically summarizes the current advances of Li anode protection in Li–S batteries regarding both fundamental understanding and regulation methodology. First, the main challenges of Li metal anode instability are introduced with emphasis on the influence from lithium polysulfides. Then, a timeline with 4 stages is presented to afford an overview of the developing history of this field. Following that, 3 Li anode protection strategies are discussed in detail in aspects of guiding uniform Li plating/stripping, reducing polysulfide concentration in anolyte, and reducing polysulfide reaction activity with Li metal. Finally, 3 viewpoints are proposed to inspire future research and development of advanced Li metal anode for practical Li–S batteries.

Abstract The stability of lithium metal anodes essentially dictates the lifespan of high‐energy‐density lithium metal batteries. Lithium nitrate (LiNO3) is widely recognized as an effective additive to stabilize lithium metal anodes by forming LiNxOy‐containing solid electrolyte interphase (SEI). However, its poor solubility in electrolytes, especially ester electrolytes, hinders its applications in lithium metal batteries. Herein, an organic nitrate, isosorbide nitrate (ISDN), is proposed to replace LiNO3. ISDN has a high solubility of 3.3 M in ester electrolytes due to the introduction of organic segments in the molecule. The decomposition of ISDN generates LiNxOy‐rich SEI, enabling uniform lithium deposition. The lifespan of lithium metal batteries with ISDN significantly increases from 80 to 155 cycles under demanding conditions. Furthermore, a lithium metal pouch cell of 439 Wh kg−1 delivers 50 cycles. This work opens a new avenue to develop additives by molecular modifications for practical lithium metal batteries.

Summary: In this protocol, we describe the quantification of electrolytes using nuclear magnetic resonance. We detail the steps involved for battery cycling, sample preparation, instrument operation, and data analysis. The protocol can be used to quantify electrolyte decomposition reactions and the apparent electron transfer numbers of different electrolyte components. The protocol is optimized for lithium-based anode-free batteries but can also be applied to other rechargeable batteries.For complete details on the use and execution of this protocol, please refer to Zhou et al. (2022).1 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.

Lithium–sulfur (Li–S) batteries are considered as a highly promising energy storage system due to their ultrahigh theoretical energy density. However, the sluggish kinetics of the complex multi-electron sulfur redox reactions seriously hinders the actual battery performance especially under practical working conditions. Homogeneous redox mediation, through elaborately designing the additive molecules, is an effective approach to promote the sulfur redox kinetics. Herein a promoter of mixed organodiselenides (mixed-Se) is proposed to comprehensively improve the sulfur redox kinetics following the redox comediation principles. Concretely, diphenyl diselenide promotes the liquid–liquid conversion between polysulfides and the solid–liquid conversion regarding lithium sulfide oxidation to polysulfides, while dimethyl diselenide enhances the liquid–solid conversion regarding lithium sulfide deposition. Consequently, the mixed-Se promoter endows a high discharge capacity of 1002 mAh g−1 with high sulfur loading of 4.0 mg cm−2, a high capacity retention of 81.6% after 200 cycles at 0.5 C, and a high actual energy density of 384 Wh kg−1 at 0.025 C in 1.5 Ah-level Li–S pouch cells. This work affords an effective kinetic promoter to construct high-energy-density Li–S batteries and inspires molecular design of kinetic promoters toward targeted energy-related redox reactions.

Oxygen reduction reaction (ORR) constitutes the core process of many energy storage and conversion devices including metal–air batteries and fuel cells. However, the kinetics of ORR is very sluggish and thus high-performance ORR electrocatalysts are highly regarded. Despite recent progress on minimizing the ORR half-wave potential as the current evaluation indicator, in-depth quantitative kinetic analysis on overall ORR electrocatalytic performance remains insufficiently emphasized. In this paper, a quantitative kinetic analysis method is proposed to afford decoupled kinetic information from linear sweep voltammetry profiles on the basis of the Koutecky–Levich equation. Independent parameters regarding exchange current density, electron transfer number, and electrochemical active surface area can be respectively determined following the proposed method. This quantitative kinetic analysis method is expected to promote understanding of the electrocatalytic effect and point out further optimization direction for ORR electrocatalysis.

Abstract Lithium–sulfur batteries are promising next‐generation energy storage devices due to their ultrahigh theoretical energy density. However, the parasitic reactions between lithium polysulfides and lithium metal anodes render lithium anodes extremely unstable during cycling and result in limited lifespan of working lithium–sulfur batteries. Herein, a Nafion protective layer is fabricated for stabilizing lithium metal anodes in working lithium–sulfur batteries. The Nafion protective layer eliminates the parasitic reactions between lithium polysulfides and lithium metal anodes. Accordingly, the cycling lifespan of lithium–sulfur batteries is doubled to 92 cycles with the Nafion protective layer using high‐sulfur‐loading cathodes and ultrathin lithium metal anodes. This study describes an effective Nafion protective layer for stabilizing lithium metal anodes and provides a possible avenue for further protective layer design for achieving long‐cycling practical lithium–sulfur batteries.

Aqueous zinc–air batteries (ZABs) are highly regarded as a promising electrochemical energy storage device owing to high energy density, low cost, and intrinsic safety. The employment of seawater to replace the currently used deionized water in electrolyte will bring great economic benefits and broaden the application occasions of ZABs. However, ZABs using seawater-based electrolyte remain uninvestigated without an applicable cathode electrocatalyst or a successful battery prototype. Herein, seawater-based electrolyte is successfully employed in ZABs with satisfactory performances. The influence of chloride anions on the cathode electrocatalytic reactivity and battery performance is systemically investigated. Both noble-metal-based and noble-metal-free electrocatalysts are applicable to the chloride-containing alkaline electrolyte. Further evaluation of ZABs with seawater-based electrolyte demonstrates comparable battery performances with the conventional electrolyte in terms of polarization, capacity, and rate performance. This study demonstrates a successful prototype of seawater-based ZABs and enlightens the utilization of natural resources for clean and sustainable energy storage.

Abstract Lithium‐sulfur (Li‐S) batteries are one of the most promising candidates for high energy density rechargeable batteries beyond current Li‐ion batteries. However, severe corrosion of Li metal anode and low Coulombic efficiency (CE) induced by the unremitting shuttle of Li polysulfides immensely hinder the practical applications of Li‐S batteries. Herein, a compact inorganic layer (CIL) formed by ex situ reactions between Li anode and ionic liquid emerged as an effective strategy to block Li polysulfides and suppress shuttle effect. A CE of 96.7% was achieved in Li‐S batteries with CIL protected Li anode in contrast to 82.4% for bare Li anode while no lithium nitrate was employed. Furthermore, the corrosion of Li during cycling was effectively inhibited. While applied to working batteries, 80.6% of the initial capacity after 100 cycles was retained in Li‐S batteries with CIL‐protected ultrathin (33 μm) Li anode compared with 58.5% for bare Li anode, further demonstrating the potential of this strategy for practical applications. This study presents a feasible interfacial regulation strategy to protect Li anode with the presence of Li polysulfides and opens avenues for Li anode protection in Li‐S batteries under practical conditions.

Abstract Lithium–sulfur (Li–S) battery is identified as one of the most promising next‐generation energy storage systems due to its ultra‐high theoretical energy density up to 2600 Wh kg−1. However, Li metal anode suffers from dramatic volume change during cycling, continuous corrosion by polysulfide electrolyte, and dendrite formation, rendering limited cycling lifespan. Considering Li metal anode as a double‐edged sword that contributes to ultrahigh energy density as well as limited cycling lifespan, it is necessary to evaluate Li‐based alloy as anode materials to substitute Li metal for high‐performance Li–S batteries. In this contribution, the authors systematically evaluate the potential and feasibility of using Li metal or Li‐based alloys to construct Li–S batteries with an actual energy density of 500 Wh kg−1. A quantitative analysis method is proposed by evaluating the required amount of electrolyte for a targeted energy density. Based on a three‐level (ideal material level, practical electrode level, and pouch cell level) analysis, highly lithiated lithium–magnesium (Li–Mg) alloy is capable to achieve 500 Wh kg−1 Li–S batteries besides Li metal. Accordingly, research on Li–Mg and other Li‐based alloys are reviewed to inspire a promising pathway to realize high‐energy‐density and long‐cycling Li–S batteries.

Abstract Lithium–sulfur (Li–S) batteries have extremely high theoretical energy density that make them as promising systems toward vast practical applications. Expediting redox kinetics of sulfur species is a decisive task to break the kinetic limitation of insulating lithium sulfide/disulfide precipitation/dissolution. Herein, we proposed a porphyrin‐derived atomic electrocatalyst to exert atomic‐efficient electrocatalytic effects on polysulfide intermediates. Quantifying electrocatalytic efficiency of liquid/solid conversion through a potentiostatic intermittent titration technique measurement presents a kinetic understanding of specific phase evolutions imparted by the atomic electrocatalyst. Benefiting from atomically dispersed “lithiophilic” and “sulfiphilic” sites on conductive substrates, the finely designed atomic electrocatalyst endows Li–S cells with remarkable cycling stablity (cyclic decay rate of 0.10% in 300 cycles), excellent rate capability (1035 mAh g−1 at 2 C), and impressive areal capacity (10.9 mAh cm−2 at a sulfur loading of 11.3 mg cm−2). The present work expands atomic electrocatalysts to the Li–S chemistry, deepens kinetic understanding of sulfur species evolution, and encourages application of emerging electrocatalysis in other multielectron/multiphase reaction energy systems.

Lithium–sulfur (Li–S) batteries are highly considered for next‐generation energy storage due to their ultrahigh theoretical energy density of 2600 Wh kg−1. The conversion reactions between lithium polysulfides (LiPSs) constitute the core process in working Li–S batteries. Electrochemical impedance spectroscopy (EIS) analysis of LiPS symmetric cells is an effective tool to provide detailed information on the LiPS conversion reactions and direct further kinetic promotion. However, reasonable interpretation of the EIS responses is so far insufficiently addressed without a well‐defined equivalent circuit. Herein, a systematic analysis on the EIS responses of LiPS symmetric cells is conducted to provide a comprehensible equivalent circuit. Interfacial contact, surface reaction, and diffusion are decoupled according to their respective characteristic frequency using the distribution of relaxation time analysis method. A well‐defined equivalent circuit is proposed to accurately fit the experimental EIS responses, unambiguously interpret key parameters, and be feasible with a wide range of experimental conditions. This work presents the methodology of understanding the EIS responses of LiPS symmetric cells and inspires analogous analysis on vital electrochemical processes.

Abstract The development of next‐generation high‐energy‐density batteries requires advanced electrode materials. Sulfurized polyacrylonitrile (SPAN) is considered a promising sulfur cathode with the merits of high specific capacity and long cycling stability for high‐performance lithium–sulfur (Li–S) batteries. Nevertheless, the practical performances of SPAN cathodes are severely limited by the unfavorable electron accessibility due to the relatively low intrinsic conductivity and large particle size. Herein, a redox mediation strategy is proposed to accelerate the electron transfer processes in working Li–S batteries with SPAN cathodes. Specifically, a quinone‐based redox mediator is introduced to provide an additional redox pathway with strengthened interfacial kinetics. The redox mediator assisted SPAN cathodes exhibit higher specific capacity, improved rate performance, reduced polarization, and longer cycling lifespan with both ether‐based and carbonate‐based electrolyte. This work demonstrates the feasibility of redox mediation to promote the electron accessibility for high‐performance Li–S batteries with SPAN cathodes.

Electrocatalysts that possess high densities of surface defects show great promise for efficient water oxidation. Here the authors demonstrate that regulating the p-block metal content in perovskite nanodots imparts these materials with abundant surface defects and excellent electrocatalytic activity.

Lithium metal constitutes promising anode materials but suffers from dendrite growth. Lithiophilic host materials are highly considered for achieving uniform lithium deposition. Precise construction of lithiophilic sites with desired structure and homogeneous distribution significantly promotes the lithiophilicity of lithium hosts but remains a great challenge. In this contribution, a framework porphyrin (POF) material with precisely constructed lithiophilic sites in regard to chemical structure and geometric position is employed as the lithium host to address the above issues for dendrite-free lithium metal anodes. The extraordinary lithiophilicity of POF even beyond lithium nuclei validated by DFT simulations and lithium nucleation overpotentials affords a novel mechanism of favorable lithium nucleation to facilitate uniform nucleation and inhibit dendrite growth. Consequently, POF-based anodes demonstrate superior electrochemical performances with high Coulombic efficiency over 98%, reduced average voltage hysteresis, and excellent stability for 300 cycles at 1.0 mA cm−2, 1.0 mAh cm−2 superior to both Cu and graphene anodes. The favorable lithium nucleation mechanism on POF materials inspires further investigation of lithiophilic electrochemistry and development of lithium metal batteries.