Lithium–sulfur (Li–S) batteries are one of the most promising next‐generation battery types for their high energy density and low cost. On the other hand, safety issues and poor cyclability strongly ...limit practical application. Solid‐state electrolytes (SSEs) can present as high ionic conductivity as aprotic electrolytes and eventually avoid the shuttle effect, which provides an ultimate solution for safe Li–S batteries with good cyclability. In this review, the recent achievements in all‐solid‐state Li–S batteries based on inorganic SSEs are summarized. Furthermore, the main attentions are paid to the interfaces, including metallic lithium|SSEs, SSEs|SSEs, and composite sulfur cathode|SSEs. The potential approaches to deal with these interfacial issues are proposed as well, such as composite SSEs with an asymmetric structure to enhance their compatibility with lithium anodes and sulfur cathodes, adding Li2O or LiF and increasing the densification to reduce the grain boundary resistance, and nanomaterials used to improve the kinetic process in cathode.
The interfaces in all‐solid‐state Li–S batteries including metallic lithium| solid‐state electrolytes (SSEs), SSEs|SSEs, and composite sulfur cathode|SSEs are surveyed and the corresponding approaches to handle the interface issues are proposed toward better electrochemical performance.
The increasing demand for replacing conventional fossil fuels with clean energy or economical and sustainable energy storage drives better battery research today. Sodium‐ion batteries (SIBs) are ...considered as a promising alternative for grid‐scale storage applications due to their similar “rocking‐chair” sodium storage mechanism to lithium‐ion batteries, the natural abundance, and the low cost of Na resources. Searching for appropriate electrode materials with acceptable electrochemical performance is the key point for development of SIBs. Layered transition metal oxides represent one of the most fascinating electrode materials owing to their superior specific capacity, environmental benignity, and facile synthesis. However, three major challenges (irreversible phase transition, storage instability, and insufficient battery performance) are known for cathodes in SIBs. Herein, a comprehensive review on the latest advances and progresses in the exploration of layered oxides for SIBs is presented, and a detailed and deep understanding of the relationship of phase transition, air stability, and electrochemical performance in layered oxide cathodes is provided in terms of refining the structure–function–property relationship to design improved battery materials. Layered oxides will be a competitive and attractive choice as cathodes for SIBs in next‐generation energy storage devices.
The recent progress in layered oxide cathodes for sodium‐ion batteries is comprehensively reviewed. Some new perspectives concentrating on phase transition, air stability, and electrochemical performance in layered cathodes are provided, in terms of refining the structure–function–property relationship to rationally design better electrode materials.
With the increasing demand for efficient and economic energy storage, Li‐S batteries have become attractive candidates for the next‐generation high‐energy rechargeable Li batteries because of their ...high theoretical energy density and cost effectiveness. Starting from a brief history of Li‐S batteries, this Review introduces the electrochemistry of Li‐S batteries, and discusses issues resulting from the electrochemistry, such as the electroactivity and the polysulfide dissolution. To address these critical issues, recent advances in Li‐S batteries are summarized, including the S cathode, Li anode, electrolyte, and new designs of Li‐S batteries with a metallic Li‐free anode. Constructing S molecules confined in the conductive microporous carbon materials to improve the cyclability of Li‐S batteries serves as a prospective strategy for the industry in the future.
Electrochemical cells with high energy densities are of great importance to satisfy the urgent demand for electronic vehicles and electricity storage. The Li‐S battery is one promising candidate, yet it suffers from the low utilization of active materials and poor cycle stability. The electrochemistry and challenges facing Li‐S batteries is addressed, and recent progress of materials related to Li‐S batteries is summarized.
Electrochemical energy storage devices with a high energy density are an important technology in modern society, especially for electric vehicles. The most effective approach to improve the energy ...density of batteries is to search for high‐capacity electrode materials. According to the concept of energy quality, a high‐voltage battery delivers a highly useful energy, thus providing a new insight to improve energy density. Based on this concept, a novel and successful strategy to increase the energy density and energy quality by increasing the discharge voltage of cathode materials and preserving high capacity is proposed. The proposal is realized in high‐capacity Li‐rich cathode materials. The average discharge voltage is increased from 3.5 to 3.8 V by increasing the nickel content and applying a simple after‐treatment, and the specific energy is improved from 912 to 1033 Wh kg−1. The current work provides an insightful universal principle for developing, designing, and screening electrode materials for high energy density and energy quality.
Li‐ion batteries with high energy quality require a high capacity coupled with high operating voltage. This requires the electrode materials to not only have a high specific capacity but also a high discharge voltage for cathode materials and low charge voltage for anode materials.
A Li3PO4 solid electrolyte interphase (SEI) layer is demonstrated to be stable in the organic electrolyte, even during the Li deposition/dissolution process. Thus, the Li‐conducting Li3PO4 SEI layer ...with a high Young's modulus can effectively reduce side reactions between Li metal and the electrolyte and can restrain Li dendrite growth in lithium‐metal batteries during cycling.
The lithium metal anode has attracted soaring attention as an ideal battery anode. Unfortunately, nonuniform Li nucleation results in uncontrollable growth of dendritic Li, which incurs serious ...safety issues and poor electrochemical performance, hindering its practical applications. Herein, this study shows that uniform Li nucleation/growth can be induced by an ultralight 3D current collector consisting of in situ nitrogen‐doped graphitic carbon foams (NGCFs) to realize suppressing dendritic Li growth at the nucleating stage. The N‐containing functional groups guide homogenous growth of Li nucleus nanoparticles and the initial Li nucleus seed layer regulates the following well‐distributed Li growth. Benefiting from such favorable Li growth behavior, superior electrochemical performance can be achieved as evidenced by the high Coulombic efficiency (≈99.6% for 300 cycles), large capacity (10 mA h cm−2, 3140 mA h g−1NGCF‐Li), and ultralong lifespan (>1200 h) together with low overpotential (<25 mV at 3 mA cm−2); even under a high current density up to 10 mA cm−2, it still displays low overpotential of 62 mV.
Uniform Li nucleation/growth can be induced by an ultralight 3D current collector consisting of in situ nitrogen‐doped graphitic carbon foams for high‐performance lithium‐metal anodes. The N‐containing functional groups guide initial homogeneous formation of Li nanoparticles and the initial nucleus seed layer regulates the even Li growth that follows. Significantly improved electrochemical performance can be achieved.
Employing small sulfur molecules as the active cathode component for room‐temperature Na‐S batteries, reveals a novel mechanism that is verified for the batteries' electrochemistry. The sulfur ...cathode enables a complete two‐electron reaction to form Na2 S, bringing a tripled specific capacity and an increased specific energy compared with traditional high‐temperature Na‐S batteries. At the same time, it offers better cycling stability endowing the batteries with a longer lifespan.
Considering the ever‐growing climatic degeneration, sustainable and renewable energy sources are needed to be effectively integrated into the grid through large‐scale electrochemical energy storage ...and conversion (EESC) technologies. With regard to their competent benefit in cost and sustainable supply of resource, room‐temperature sodium‐ion batteries (SIBs) have shown great promise in EESC, triumphing over other battery systems on the market. As one of the most fascinating cathode materials due to the simple synthesis process, large specific capacity, and high ionic conductivity, Na‐based layered transition metal oxide cathodes commonly suffer from the sluggish kinetics, multiphase evolution, poor air stability, and insufficient comprehensive performance, restricting their commercialization application. Here, this review summarizes the recent advances in layered oxide cathode materials for SIBs through different optimal structure modulation technologies, with an emphasis placed on strategies to boost Na+ kinetics and reduce the irreversible phase transition as well as enhance the store stability. Meanwhile, a thorough and in‐depth systematical investigation of the structure–function–property relationship is also discussed, and the challenges as well as opportunities for practical application electrode materials are sketched. The insights brought forward in this review can be considered as a guide for SIBs in next‐generation EESC.
The recent research progress of structure modulation technology on layered transition metal oxide cathodes for sodium‐ion batteries is summarized, concentrating especially on morphology design, coating technology, phase transition, ordering‐disordering, air stability, and composite structure to boost Na+ kinetics, suppress the irreversible phase transition, enhance the storage stability, improve the overall performance, and further realize sodium‐ion battery commercialization for market applications.
The Li metal anode has long been considered as one of the most ideal anodes due to its high energy density. However, safety concerns, low efficiency, and huge volume change are severe hurdles to the ...practical application of Li metal anodes, especially in the case of high areal capacity. Here it is shown that that graphitized carbon fibers (GCF) electrode can serve as a multifunctional 3D current collector to enhance the Li storage capacity. The GCF electrode can store a huge amount of Li via intercalation and electrodeposition reactions. The as‐obtained anode can deliver an areal capacity as high as 8 mA h cm−2 and exhibits no obvious dendritic formation. In addition, the enlarged surface area and porous framework of the GCF electrode result in lower local current density and mitigate high volume change during cycling. Thus, the Li composite anode displays low voltage hysteresis, high plating/stripping efficiency, and long lifespan. The multifunctional 3D current collector promisingly provides a new strategy for promoting the cycling lifespan of high areal capacity Li anodes.
Graphitized carbon fiber electrode is demonstrated to improve the cycling performance of high‐areal‐capacity Li anodes due to dual reaction types, reduced current density, and confined volume change. This Li anode can deliver a high areal capacity of 8 mA h cm−2 without Li dendrites and displays low voltage hysteresis, high plating/stripping efficiency, and long cycling lifespan.
A sandwich‐like hierarchically porous carbon/graphene (G@HPC) composite is synthesized using a facile ionothermal process. The composite exhibits high specific capacity, remarkable cycling stability, ...and high‐rate capability because of the synergistic effect of low‐graphitized porous carbon with hierarchical structure and highly conductive graphene sandwiched between porous carbons.
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