Recent Advances in Transition-Metal-Based Catalytic Material for Room-Temperature Sodium–Sulfur Batteries

Room-temperature sodium–sulfur (RT Na–S) batteries have emerged as a promising candidate for next-generation scalable energy storage systems, due to their high theoretical energy density, low cost, and natural abundance. However, the practical applications of these batteries are hindered by the notorious shuttle effect of soluble sodium polysulfides (NaPSs) and sluggish reaction kinetics, which result in fast performance loss. To address this issue, recent studies have reported impressive achievements of transition metal nanoparticles/single atoms/cluster/compounds (TM)-based host materials with strong adsorption and catalyzation to NaPSs. These materials can significantly improve the electrochemical performance of RT Na–S batteries. In this review, the recent progress on TM-based host materials for RT Na–S batteries, including iron (Fe)-, cobalt (Co)-, nickel (Ni)-, molybdenum (Mo)-, titanium (Ti)-, vanadium (V)-, manganese (Mn)-, and other TM-based materials are summarized. The design, fabrication, and properties of these host materials are comprehensively summarized and systematically analyzed the underlying chemical inhibition and electrocatalysis mechanism between NaPSs and TM-based catalytic materials. At last, the challenges and prospects for designing efficient TM-based catalytic materials for high-performance RT Na–S batteries are discussed

Constructing LiCl-Rich Solid Electrolyte Interphase by High Amine-Containing 1,2,4,5-Benzenetetramine Tetrahydrochloride Additive

Strategies that aim to achieve highly stable lithium metal batteries (LMBs) are extensively explored. To date, the controlled formation of high-quality inorganic SEI is still quite challenging, which requires a deep understanding and hence the fine-tuning of solvation chemistry by using functional additives in the electrolyte. In this work, a high amine-containing 1,2,4,5-benzenetetramine tetrahydrochloride (BHCL) is developed as a dual-function electrolyte additive for LMBs. The amine group with a high donor number increases the lithium affinity, while the phenyl group with a strong inductive effect prevents the decomposition of solvents, and the free chloride ions replace anions mediating the formation of the rigid inorganic LiCl-rich SEI layer. The experimental results corroborate the theoretical findings. The modified Li||Li symmetric battery is stably cycled for over 2500 h at 1 mA cm−2 current density with an overpotential of ≈45 mV. The performances of the Li||Cu and Li||LFP cells are also significantly enhanced. Therefore, this work provides a promising design principle of multifunctional electrolyte additive.Li symmetric battery is stably cycled for over 2500 h at 1 mA cm−2 current density with an overpotential of ≈45 mV. The performances of the LiCu and LiLFP cells are also significantly enhanced. Therefore, this work provides a promising design principle of multifunctional electrolyte additive

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

Molybdenum-Based Catalytic Materials for Li–S Batteries: Strategies, Mechanisms, and Prospects

Lithium–sulfur (Li–S) batteries are regarded as promising candidates for high-energy storage devices because of their high theoretical energy density (2600 Wh kg−1). However, their practical applications are still hindered by a multitude of key challenges, especially the shuttle effect of soluble lithium polysulfides (LiPSs) and the sluggish sulfur redox kinetics. To address these challenges, varieties of catalytic materials have been exploited to prevent the shuttle effect and accelerate the LiPSs conversion. Recently, molybdenum-based (Mo-based) catalytic materials are widely used as sulfur host materials, modified separators, and interlayers for Li–S batteries. They include the Mo sulfides, diselenides, carbides, nitrides, oxides, phosphides, borides, and metal/single atoms/clusters. Here, recent advances in these Mo-based catalytic materials are comprehensively summarized, and the current challenges and prospects for designing highly efficient Mo-based catalytic materials are highlighted, with the aim to provide a fundamental understanding of the sulfur reaction mechanism, and to guide the rational design of cathode catalysts for high-energy and long-life Li–S batteries

Nitrogen Doping Improves the Immobilization and Catalytic Effects of Co9S8 in Li-S Batteries

Several critical issues, such as the shuttling effect and the sluggish reaction kinetics, exist in the design of high-performance lithium–sulfur (Li-S) batteries. Here, it is reported that nitrogen doping can simultaneously and significantly improve both the immobilization and catalyzation effects of Co9S8 nanoparticles in Li-S batteries. Combining the theoretical calculations with experimental investigations, it is revealed that nitrogen atoms can increase the binding energies between LiPSs and Co9S8, and as well as alleviate the sluggish kinetics of Li-S chemistry in the Li2S6 cathode. The same effects are also observed when adding N-Co9S8 nanoparticles into the commercial Li2S cathode (which has various intrinsic advantages, but unfortunately a high overpotential). A remarkable improvement in the battery performances in both cases is observed. The work brings heteroatom-doped Co9S8 to the attention of designing high-performance Li-S batteries. A fundamental understanding of the inhibition of LiPSs shuttle and the catalytic effect of Li2S in the newly developed system may encourage more effort along this interesting direction. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Tungsten Nanoparticles Accelerate Polysulfides Conversion: A Viable Route toward Stable Room-Temperature Sodium–Sulfur Batteries

Room-temperature sodium–sulfur (RT Na–S) batteries are arousing great interest in recent years. Their practical applications, however, are hindered by several intrinsic problems, such as the sluggish kinetic, shuttle effect, and the incomplete conversion of sodium polysulfides (NaPSs). Here a sulfur host material that is based on tungsten nanoparticles embedded in nitrogen-doped graphene is reported. The incorporation of tungsten nanoparticles significantly accelerates the polysulfides conversion (especially the reduction of Na2S4 to Na2S, which contributes to 75% of the full capacity) and completely suppresses the shuttle effect, en route to a fully reversible reaction of NaPSs. With a host weight ratio of only 9.1% (about 3–6 times lower than that in recent reports), the cathode shows unprecedented electrochemical performances even at high sulfur mass loadings. The experimental findings, which are corroborated by the first-principles calculations, highlight the so far unexplored role of tungsten nanoparticles in sulfur hosts, thus pointing to a viable route toward stable Na–S batteries at room temperatures

Constructing LiCl‐Rich Solid Electrolyte Interphase by High Amine‐Containing 1,2,4,5‐Benzenetetramine Tetrahydrochloride Additive

Abstract Strategies that aim to achieve highly stable lithium metal batteries (LMBs) are extensively explored. To date, the controlled formation of high‐quality inorganic SEI is still quite challenging, which requires a deep understanding and hence the fine‐tuning of solvation chemistry by using functional additives in the electrolyte. In this work, a high amine‐containing 1,2,4,5‐benzenetetramine tetrahydrochloride (BHCL) is developed as a dual‐function electrolyte additive for LMBs. The amine group with a high donor number increases the lithium affinity, while the phenyl group with a strong inductive effect prevents the decomposition of solvents, and the free chloride ions replace anions mediating the formation of the rigid inorganic LiCl‐rich SEI layer. The experimental results corroborate the theoretical findings. The modified Li||Li symmetric battery is stably cycled for over 2500 h at 1 mA cm−2 current density with an overpotential of ≈45 mV. The performances of the Li||Cu and Li||LFP cells are also significantly enhanced. Therefore, this work provides a promising design principle of multifunctional electrolyte additive

Monodisperse Molybdenum Nanoparticles as Highly Efficient Electrocatalysts for Li-S Batteries

Lithium-sulfur (Li-S) batteries have attracted widespread attention due to their high theoretical energy density. However, their practical application is still hindered by the shuttle effect and the sluggish conversion of lithium polysulfides (LiPSs). Herein, monodisperse molybdenum (Mo) nanoparticles embedded onto nitrogen-doped graphene (Mo@N-G) were developed and used as a highly efficient electrocatalyst to enhance LiPS conversion. The weight ratio of the electrocatalyst in the catalyst/sulfur cathode is only 9%. The unfilled d orbitals of oxidized Mo can attract the electrons of LiPS anions and form Mo–S bonds during the electrochemical process, thus facilitating fast conversion of LiPSs. Li-S batteries based on the Mo@N-G/S cathode can exhibit excellent rate performance, large capacity, and superior cycling stability. Moreover, Mo@N-G also plays an important role in room-temperature quasi-solid-state Li-S batteries. These interesting findings suggest the great potential of Mo nanoparticles in building high-performance Li-S batteries