For seeking high enantiopurity, the previously reported thermal asymmetric catalysis is usually carried out at low temperature sometimes with limited yield, that is, the high enantiomeric excess (ee) ...usually at the cost of high yield. Thus, the achieving both high stereoselectivity and yield is an enormous challenge. We report herein two metal nanoparticle (M NP)-loaded and porphyrin-containing homochiral covalent organic framework (CCOF)-based composite catalysts, and their application in the thermally-driven asymmetric one-pot Henry and A
-coupling reactions. All the reactions are conducted at elevated temperatures with both excellent stereoselectivity and yield which resulted from the synergy of CCOF confinement effect and M NP catalytic activation. Notably, the needed thermal energy for the asymmetric reactions herein is derived from the photothermal conversion via porphyrin-based CCOF upon irradiation with visible light. Remarkably, the CCOF confinement effect can be effectively maintained up to 100 °C for the asymmetric one-pot Henry and A
-coupling reactions herein.
Lithium (Li) metal is one of the most promising alternative anode materials of next‐generation high‐energy‐density batteries demanded for advanced energy storage in the coming fourth industrial ...revolution. Nevertheless, disordered Li deposition easily causes short lifespan and safety concerns and thus severely hinders the practical applications of Li metal batteries. Tremendous efforts are devoted to understanding the mechanism for Li deposition, while the final deposition morphology tightly relies on the Li nucleation and early growth. Here, the recent progress in insightful and influential models proposed to understand the process of Li deposition from nucleation to early growth, including the heterogeneous model, surface diffusion model, crystallography model, space charge model, and Li‐SEI model, are highlighted. Inspired by the abovementioned understanding on Li nucleation and early growth, diverse anode‐design strategies, which contribute to better batteries with superior electrochemical performance and dendrite‐free deposition behavior, are also summarized. This work broadens the horizon for practical Li metal batteries and also sheds light on more understanding of other important metal‐based batteries involving the metal deposition process.
Lithium (Li) nucleation and early growth processes significantly determine the final deposition behavior. The recent progress in influential models proposed to understand the process of Li nucleation and early growth is highlighted. Inspired by the abovementioned understanding, diverse anode‐design strategies, which contribute to better batteries with superior electrochemical performance and dendrite‐free deposition behavior, are also summarized.
Solid‐state batteries enabled by solid‐state polymer electrolytes (SPEs) are under active consideration for their promise as cost‐effective platforms that simultaneously support high‐energy and safe ...electrochemical energy storage. The limited oxidative stability and poor interfacial charge transport in conventional polymer electrolytes are well known, but difficult challenges must be addressed if high‐voltage intercalating cathodes are to be used in such batteries. Here, ether‐based electrolytes are in situ polymerized by a ring‐opening reaction in the presence of aluminum fluoride (AlF3) to create SPEs inside LiNi0.6Co0.2 Mn0.2O2 (NCM) || Li batteries that are able to overcome both challenges. AlF3 plays a dual role as a Lewis acid catalyst and for the building of fluoridized cathode–electrolyte interphases, protecting both the electrolyte and aluminum current collector from degradation reactions. The solid‐state NCM || Li metal batteries exhibit enhanced specific capacity of 153 mAh g−1 under high areal capacity of 3.0 mAh cm−2. This work offers an important pathway toward solid‐state polymer electrolytes for high‐voltage solid‐state batteries.
Solid‐state batteries are under active consideration for their promise as cost‐effective platforms that simultaneously support high‐energy and safe electrochemical energy storage. In this work, ether‐based solid‐state polymer electrolytes are created inside a battery using ring‐opening polymerization in the presence of aluminum fluoride (AlF3). The electrolytes are shown to mitigate cathode corrosion and to enable solid‐state LiNi0.6Co0.2 Mn0.2O2 (NCM)||Li batteries with high capacities.
High‐dielectric solvents were explored for enhancing the sulfur utilization in lithium–sulfur (Li−S) batteries, but their applications have been impeded by low stability at the lithium metal anode. ...Now a radical‐directed, lithium‐compatible, and strongly polysulfide‐solvating high‐dielectric electrolyte based on tetramethylurea is presented. Over 200 hours of cycling was realized in Li|Li symmetric cells, showing good compatibility of the tetramethylurea‐based electrolyte with lithium metal. The high solubility of short‐chain polysulfides, as well as the presence of active S3.− radicals, enabled pouch cells to deliver a discharge capacity of 1524 mAh g−1 and an energy density of 324 Wh kg−1. This finding suggests an alternative recipe to ether‐based electrolytes for Li−S batteries.
Li−S batteries: A lithium‐compatible and strongly polysulfide‐solvating high‐dielectric electrolyte based on tetramethylurea was proposed to direct a solvation‐mediated radical reaction pathway. It enables Li−S pouch cells to deliver an energy density of 324 Wh kg−1. Key: red=electrochemical, black=chemical, dashed=diffusion/precipitation.
Solid‐state lithium (Li) metal batteries (SSLMBs) have become a research hotspot in the energy storage field due to the much‐enhanced safety and high energy density. However, the SSLMBs suffer from ...failures including dendrite‐induced short circuits and contact‐loss‐induced high impedance, which are highly related to the Li plating/stripping kinetics and hinder the practical application of SSLMBs. The maximum endurable current density of lithium battery cycling without cell failure in SSLMB is generally defined as critical current density (CCD). Therefore, CCD is an important parameter for the application of SSLMBs, which can help to determine the rate‐determining steps of Li kinetics in solid‐state batteries. Herein, the theoretical and practical meanings for CCD from the fundamental thermodynamic and kinetic principles, failure mechanisms, CCD identifications, and influence factors for improving CCD performances are systematically reviewed. Based on these fundamental understandings, a series of strategies and outlooks for future researches on SSLMB are presented, endeavoring on increasing CCD for practical SSLMBs.
The critical current density (CCD) is an important standard for future solid‐state Li metal batteries (SSLMBs), which is highly related to power density and fast charge capability. The CCD can help to unravel the rate determining factors of Li kinetics including special mass transport and charge transfer at solid–solid interfaces.
Fast charging enables electronic devices to be charged in a very short time, which is essential for next‐generation energy storage systems. However, the increase of safety risks and low coulombic ...efficiency resulting from fast charging severely hamper the practical applications of this technology. This Review summarizes the challenges and recent progress of lithium batteries for fast charging. First, it describes the definition of fast charging and proposes a critical value of ionic and electrical conductivity of electrodes for fast charging in a working battery. Then based on this definition, the requirements and optimization strategies of the electrode, electrolyte, and electrode/electrolyte interface for fast charging are proposed. Finally, a general conclusion and perspectives on the better understanding of lithium batteries with fast charging capability are presented.
The fast charging of rechargeable batteries is reviewed and the critical values of ionic and electrical conductivity of electrodes that are employed in fast charging are also proposed. The requirements of electrode, solid electrolytes, and their interfaces are also presented to meet the practical application in fast charging batteries.
Lithium Bonds in Lithium Batteries Chen, Xiang; Bai, Yun‐Ke; Zhao, Chen‐Zi ...
Angewandte Chemie International Edition,
July 6, 2020, Volume:
59, Issue:
28
Journal Article
Peer reviewed
Lithium bonds are analogous to hydrogen bonds and are therefore expected to exhibit similar characteristics and functions. Additionally, the metallic nature and large atomic radius of Li bestow the ...Li bond with special features. As one of the most important applications of the element, Li batteries afford emerging opportunities for the exploration of Li bond chemistry. Herein, the historical development and concept of the Li bond are reviewed, in addition to the application of Li bonds in Li batteries. In this way, a comprehensive understanding of the Li bond in Li batteries and an outlook on its future developments is presented.
Lithium bonds that are present in lithium batteries are discussed in this Viewpoint, including historical developments, comparisons with hydrogen bonds, and their potential applications. Discourse on the chemistry of the Li bond can provide fruitful insight into the fundamental interactions within Li batteries and thus deliver a deeper understanding of their working mechanism.
In recent years, the rapid development of modern society is calling for advanced energy storage to meet the growing demands of energy supply and generation. As one of the most promising energy ...storage systems, secondary batteries are attracting much attention. The electrolyte is an important part of the secondary battery, and its composition is closely related to the electrochemical performance of the secondary batteries. Lithium‐ion battery electrolyte is mainly composed of solvents, additives, and lithium salts, which are prepared according to specific proportions under certain conditions and according to the needs of characteristics. This review analyzes the advantages and current problems of the liquid electrolytes in lithium‐ion batteries (LIBs) from the mechanism of action and failure mechanism, summarizes the research progress of solvents, lithium salts, and additives, analyzes the future trends and requirements of lithium‐ion battery electrolytes, and points out the emerging opportunities in advanced lithium‐ion battery electrolytes development.
This review analyzes the advantages and current problems of the liquid electrolytes in lithium‐ion batteries from the mechanism of action and failure mechanism, summarizes the research progress of solvents, lithium salts, and additives, analyzes the future trends and requirements of lithium‐ion battery electrolytes, and points out the emerging opportunities in advanced lithium‐ion battery electrolytes development.
Harnessing data to discover the underlying governing laws or equations that describe the behavior of complex physical systems can significantly advance our modeling, simulation and understanding of ...such systems in various science and engineering disciplines. This work introduces a novel approach called physics-informed neural network with sparse regression to discover governing partial differential equations from scarce and noisy data for nonlinear spatiotemporal systems. In particular, this discovery approach seamlessly integrates the strengths of deep neural networks for rich representation learning, physics embedding, automatic differentiation and sparse regression to approximate the solution of system variables, compute essential derivatives, as well as identify the key derivative terms and parameters that form the structure and explicit expression of the equations. The efficacy and robustness of this method are demonstrated, both numerically and experimentally, on discovering a variety of partial differential equation systems with different levels of data scarcity and noise accounting for different initial/boundary conditions. The resulting computational framework shows the potential for closed-form model discovery in practical applications where large and accurate datasets are intractable to capture.
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