Stabilizing Lithium into Cross‐Stacked Nanotube Sheets with an Ultra‐High Specific Capacity for Lithium Oxygen Batteries

Although lithium–oxygen batteries possess a high theoretical energy density and are considered as promising candidates for next‐generation power systems, the enhancement of safety and cycling efficiency of the lithium anodes while maintaining the high energy storage capability remains difficult. Here, we overcome this challenge by cross‐stacking aligned carbon nanotubes into porous networks for ultrahigh‐capacity lithium anodes to achieve high‐performance lithium–oxygen batteries. The novel anode shows a reversible specific capacity of 3656 mAh g^?1, approaching the theoretical capacity of 3861 mAh g^?1 of pure lithium. When this anode is employed in lithium–oxygen full batteries, the cycling stability is significantly enhanced, owing to the dendrite‐free morphology and stabilized solid–electrolyte interface. This work presents a new pathway to high performance lithium–oxygen batteries towards practical applications by designing cross‐stacked and aligned structures for one‐dimensional conducting nanomaterials.     

The Three‐Dimensional Dendrite‐Free Zinc Anode on a Copper Mesh with a Zinc‐Oriented Polyacrylamide Electrolyte Additive

Rechargeable aqueous zinc‐ion batteries have been considered as a promising candidate for next‐generation batteries. However, the formation of zinc dendrites are the most severe problems limiting their practical applications. To develop stable zinc metal anodes, a synergistic method is presented that combines the Cu‐Zn solid solution interface on a copper mesh skeleton with good zinc affinity and a polyacrylamide electrolyte additive to modify the zinc anode, which can greatly reduce the overpotential of the zinc nucleation and increase the stability of zinc deposition. The as‐prepared zinc anodes show a dendrite‐free plating/stripping behavior over a wide range of current densities. The symmetric cell using this dendrite‐free anode can be cycled for more than 280 h with a very low voltage hysteresis (93.1 mV) at a discharge depth of 80 %. The high capacity retention and low polarization are also realized in Zn/MnO₂ full cells.     

Columnar Lithium Metal Anodes

The rechargeable lithium metal anode is of utmost importance for high‐energy‐density batteries. Regulating the deposition/dissolution characteristics of Li metal is critical in both fundamental researches and practical applications. In contrast to gray Li deposits featured with dendritic and mossy morphologies, columnar and uniform Li is herein plated on lithium‐fluoride (LiF)‐protected copper (Cu) current collectors. The electrochemical properties strongly depended on the microscale morphologies of deposited Li, which were further embodied as macroscale colors. The as‐obtained ultrathin and columnar Li anodes contributed to stable cycling in working batteries with a dendrite‐free feature. This work deepens the fundamental understanding of the role of LiF in the nucleation/growth of Li and provides emerging approaches to stabilize rechargeable Li metal anodes.     

Columnar Lithium Metal Anodes

The rechargeable lithium metal anode is of utmost importance for high‐energy‐density batteries. Regulating the deposition/dissolution characteristics of Li metal is critical in both fundamental researches and practical applications. In contrast to gray Li deposits featured with dendritic and mossy morphologies, columnar and uniform Li is herein plated on lithium‐fluoride (LiF)‐protected copper (Cu) current collectors. The electrochemical properties strongly depended on the microscale morphologies of deposited Li, which were further embodied as macroscale colors. The as‐obtained ultrathin and columnar Li anodes contributed to stable cycling in working batteries with a dendrite‐free feature. This work deepens the fundamental understanding of the role of LiF in the nucleation/growth of Li and provides emerging approaches to stabilize rechargeable Li metal anodes.     

Electrolyte Chemistry Enables Simultaneous Stabilization of Potassium Metal and Alloying Anode for Potassium‐Ion Batteries

Alloying anodes are promising high‐capacity electrode materials for K‐ion batteries (KIBs). However, KIBs based on alloying anodes suffer from rapid capacity decay due to the instability of K metal and large volume expansion of alloying anodes. Herein, the effects of salts and solvents on the cycling stability of KIBs based on a typical alloying anode such as amorphous red phosphorus (RP) are investigated, and the potassium bis(fluorosulfonyl)imide (KFSI) salt‐based carbonate electrolyte is versatile to achieve simultaneous stabilization of K metal and RP electrodes for highly stable KIBs. This salt‐solvent complex with a moderate solvation energy can alleviate side reactions between K metal and the electrolyte and facilitate K⁺ ion diffusion/desolvation. Moreover, robust SEI layers that form on K metal and RP electrodes can suppress K dendrite growth and resist RP volume change. This strategy of electrolyte regulation can be applicable to other alloying anodes for high‐performance KIBs.     

Selective nitrogen doping on carbon cloth to enhance the performance of zinc anode

Metallic zinc is attractive anode material of rechargeable aqueous Zn-based batteries due to its ambient stability,high volumetric capacity,and abundant reserves.Nonetheless,Zn anodes suffer from issues such as low coulombic efficiency(CE),large polarization and dendrite formation.Herein,uniform Zn electrodeposition is reported on carbon substrates by selective nitrogen doping.Combined experimental and theoretical investigations demonstrate that pyrrolic and pyridinic nitrogen doped in carbon play beneficial effect as zinc-philic sites to direct nucleation and growth of metallic Zn,while negligible effect is observed for graphite nitrogen in Zn plating.The carbon cloth with modified amount of doped pyrrolic and pyridinic nitrogen stabilizes Zn plating/stripping with 99.3% CE after 300 cycles and significantly increases the deliverable capacity at high depth of charge and discharge compared to undoped carbon substrate and Zn foil.This work provides a better understanding of heteroatom doping effect in design and preparation of stable 3 D carbon-supported zinc anode.     

Temperature‐Dependent Nucleation and Growth of Dendrite‐Free Lithium Metal Anodes

It is essential to develop a facile and effective method to enhance the electrochemical performance of lithium metal anodes for building high‐energy‐density Li‐metal based batteries. Herein, we explored the temperature‐dependent Li nucleation and growth behavior and constructed a dendrite‐free Li metal anode by elevating temperature from room temperature (20 °C) to 60 °C. A series of ex situ and in situ microscopy investigations demonstrate that increasing Li deposition temperature results in large nuclei size, low nucleation density, and compact growth of Li metal. We reveal that the enhanced lithiophilicity and the increased Li‐ion diffusion coefficient in aprotic electrolytes at high temperature are essential factors contributing to the dendrite‐free Li growth behavior. As anodes in both half cells and full cells, the compact deposited Li with minimized specific surface area delivered high Coulombic efficiencies and long cycling stability at 60 °C.     

Recent Progress in Aqueous Zinc-Ion Batteries: From FundamentalScience to Structure Design

Rechargeable aqueous zinc-ion batteries (ZIB) sparked a considerable surge of research attention in energy storage systems due to its environment benignity and superior electrochemical performance. Up to now, less efforts to delve into mechanisms of zinc metal anode and their electrochemical performance. Zn metal anodes sustain thorny issues with Zn dendrite growth, hydrogen evolution reaction, and Zn corrosion irreversible byproduct formation, which results in low coulomb efficiency (CE) and poor cycle ability of the battery. Herein, we reveal the fundamental understanding of the above issue, outline four step, including mass transfer, desolvation process, charge transfer and Zn cluster formation. It can be clearly seen from reported strategies to promote Zn anode stability that deals with one or more steps, thereby boosting the understanding of the issues of Zn anodes and benefiting the rational design to surmount the issue. We also sum up advanced materials and structure design such as the design of the anode surface and internal structure, electrolyte strategies, and multifunctional separators. Finally, possible tactics and future innovation direction for Zn-based batteries are proposed to achieve high performance aqueous Zinc-ion batteries.     

A Bio-Inspired Trehalose Additive for Reversible Zinc Anodes with Improved Stability and Kinetics

The moderate reversibility of Zn anodes, as a long-standing challenge in aqueous zinc-ion batteries, promotes the exploration of suitable electrolyte additives continuously. It is crucial to establish the absolute predominance of smooth deposition within multiple interfacial reactions for stable zinc anodes, including suppressing side parasitic reactions and facilitating Zn plating process. Trehalose catches our attention due to the reported mechanisms in sustaining biological stabilization. In this work, the inter-disciplinary application of trehalose is reported in the electrolyte modification for the first time. The pivotal roles of trehalose in suppressed hydrogen evolution and accelerated Zn deposition have been investigated based on the principles of thermodynamics as well as reaction kinetics. The electrodeposit changes from random accumulation of flakes to dense bulk with (002)-plane exposure due to the unlocked crystal-face oriented deposition with trehalose addition. As a result, the highly reversible Zn anode is obtained, exhibiting a high average CE of 99.8 % in the Zn/Cu cell and stable cycling over 1500 h under 9.0 % depth of discharge in the Zn symmetric cell. The designing principles and mechanism analysis in this study could serve as a source of inspiration in exploring novel additives for advanced Zn anodes.     

In situ Implanting 3D Carbon Network Reinforced Zinc Composite by Powder Metallurgy for Highly Reversible Zn-based Battery Anodes

Aqueous Zn-based batteries have emerged as compelling candidates for grid-scale energy storage, owing to their intrinsic safety, remarkable theoretical energy density and cost-effectiveness. Nonetheless, the dendrite formation, side reactions, and corrosion on anode have overshadowed their practical applications. Herein, we present an in situ grown carbon network reinforcing Zn matrix anode prepared by powder metallurgy. This carbon network provides an uninterrupted internal electron transport pathway and optimize the surface electric field distribution, thereby enabling highly reversible Zn deposition. Consequently, symmetrical cells demonstrate impressive stability, running for over 880 h with a low voltage hysteresis (≈32 mV). Furthermore, this Zn matrix composite anode exhibits enhanced performance in both the aqueous Zn-ion and the Zn-air batteries. Notably, Zn//MnO₂ cells display superior rate capabilities, while Zn-air batteries deliver high power density and impressive Zn utilization rate (84.9 %). This work provides a new idea of powder metallurgy method for modified Zn anodes, showcasing potential for large-scale production.     

A Two‐Dimensional Mesoporous Polypyrrole–Graphene Oxide Heterostructure as a Dual‐Functional Ion Redistributor for Dendrite‐Free Lithium Metal Anodes

Guiding the lithium ion (Li‐ion) transport for homogeneous, dispersive distribution is crucial for dendrite‐free Li anodes with high current density and long‐term cyclability, but remains challenging for the unavailable well‐designed nanostructures. Herein, we propose a two‐dimensional (2D) heterostructure composed of defective graphene oxide (GO) clipped on mesoporous polypyrrole (mPPy) as a dual‐functional Li‐ion redistributor to regulate the stepwise Li‐ion distribution and Li deposition for extremely stable, dendrite‐free Li anodes. Owing to the synergy between the Li‐ion transport nanochannels of mPPy and the Li‐ion nanosieves of defective GO, the 2D mPPy‐GO heterostructure achieves ultralong cycling stability (1000 cycles), even tests at 0 and 50 °C, and an ultralow overpotential of 70 mV at a high current density of 10.0 mA cm^?2, outperforming most reported Li anodes. Furthermore, mPPy‐GO‐Li/LiCoO₂ full batteries demonstrate remarkably enhanced performance with a capacity retention of >90 % after 450 cycles. Therefore, this work opens many opportunities for creating 2D heterostructures for high‐energy‐density Li metal batteries.     

Electrolyte Regulation towards Stable Lithium‐Metal Anodes in Lithium–Sulfur Batteries with Sulfurized Polyacrylonitrile Cathodes

Lithium–sulfur (Li–S) batteries are highly regarded as the next‐generation energy‐storage devices because of their ultrahigh theoretical energy density of 2600 Wh kg^?1. Sulfurized polyacrylonitrile (SPAN) is considered a promising sulfur cathode to substitute carbon/sulfur (C/S) composites to afford higher Coulombic efficiency, improved cycling stability, and potential high‐energy‐density Li–SPAN batteries. However, the instability of the Li‐metal anode threatens the performances of Li–SPAN batteries bringing limited lifespan and safety hazards. Li‐metal can react with most kinds of electrolyte to generate a protective solid electrolyte interphase (SEI), electrolyte regulation is a widely accepted strategy to protect Li‐metal anodes in rechargeable batteries. Herein, the basic principles and current challenges of Li–SPAN batteries are addressed. Recent advances on electrolyte regulation towards stable Li‐metal anodes in Li–SPAN batteries are summarized to suggest design strategies of solvents, lithium salts, additives, and gel electrolyte. Finally, prospects for future electrolyte design and Li anode protection in Li–SPAN batteries are discussed.     

Self‐Stabilized and Strongly Adhesive Supramolecular Polymer Protective Layer Enables Ultrahigh‐Rate and Large‐Capacity Lithium‐Metal Anode

Constructing a solid electrolyte interface (SEI) is a highly effective approach to overcome the poor reversibility of lithium (Li) metal anodes. Herein, an adhesive and self‐healable supramolecular copolymer, comprising of pendant poly(ethylene oxide) (PEO) segments and ureido‐pyrimidinone (UPy) quadruple‐hydrogen‐bonding moieties, is developed as a protection layer of Li anode by a simple drop‐coating. The protection performance of in‐situ‐formed LiPEO–UPy SEI layer is significantly enhanced owing to the strong binding and improved stability arising from a spontaneous reaction between UPy groups and Li metal. An ultrathin (approximately 70 nm) LiPEO–UPy layer can contribute to stable and dendrite‐free cycling at a high areal capacity of 10 mAh cm^?2 at 5 mA cm^?2 for 1000 h. This coating together with the promising electrochemical performance offers a new strategy for the development of dendrite‐free metal anodes.     

Flexible Amalgam Film Enables Stable Lithium Metal Anodes with High Capacities

Dendrite formation is a critical challenge for the applications of lithium (Li) metal anodes. In this work a new strategy is demonstrated to address this issue by fabricating an Li amalgam film on its surface. This protective film serves as a flexible buffer that affords repeated Li plating/stripping. In symmetric cells, the protected Li electrodes exhibit stable cycling over 750 hours at a high plating current and capacity of 8 mA cm^?2 and 8 mAh cm^?2, respectively. Coupled with high‐loading cathodes (ca. 12 mg cm^?2) such as LiFePO₄ and LiNi_0.6Co_0.2Mn_0.2O₂, the protected hybrid anodes demonstrate significantly improved cell stability, indicating its reliability for practical development of Li metal batteries. Interfacial analyses reveal a unique plating‐alloying synergistic function of the protective film, where Li beneath the film is actively involved in the electrode reactions upon cycling. Lithium amalgams enrich the alloy anode family and provide new perspectives for the rational design of dendrite‐free anodes.     

Electrical-Conductive/Insulating Bi-Functional Layers for Stable Zn Metal Anode

Zinc-ion batteries are regarded as an extremely promising candidate for large-scale energy storage equipment due to the inexpensive ingredients and high safety. However, dendrite growth and side reactions occur in the Zn anode, which lead to exceedingly low coulombic efficiency (CE) and poor cycling stability. In this work, we propose a strategy of a conductive/insulating bi-functional coating layer (CIBL) for stable Zn metal anodes. Porous Ag nanowires (NWs) coating as a conductive layer effectively reduces the nuclear barrier and contains Zn²⁺ deposition in a certain space. Polyimide (PI) coatings as insulating layer implement a shunting effect on Zn²⁺, which could reduce the differential concentration on the Zn surface and induce uniform deposition of Zn²⁺. Therefore, the CIBL−Zn//CIBL−Zn battery achieves stable plating/stripping of over 1300 h at 1 mA cm⁻². The CE of CIBL−Zn//CIBL−Zn battery maintains at 99.2 % even after 1000 cycles. Moreover, the CIBL−Zn//V₂O₅ battery exhibits a capacity of nearly 289.2 mA h g⁻¹ at 5 A g⁻¹ after 3000 cycles and no sign of capacity degradation is found, which further demonstrate the feasibility of this strategy in practical application.     

担载纳米硅的锂-碳复合微球作为锂二次电池负极

金属锂由于其极高的理论比容量(3860mAh·g~(-1),2061mAh·cm~(-3))和低的还原电势(相对于标准氢电极(SHE)为-3.04 V)等特点,成为了高能量密度锂电池负极材料的极佳选择之一。从上个世纪七十年代开始,科研工作者便开始了金属锂负极的研究,然而,由于金属锂与电解液反应严重,镀锂过程体积膨胀大,且在循环中易生成枝晶,以金属锂为负极的电池循环稳定性差,而且容易短路从而带来安全隐患。因此金属锂做为锂电池负极的商业化推广最终没有成功。在本工作中,我们在前期设计的锂-碳纳米管复合微球(Li-CNT)中引入了纳米硅颗粒制备了硅颗粒担载的锂-碳复合球(LiCNT-Si)。实验发现,纳米硅颗粒的加入不仅提高了锂-碳复合微球的载锂量(10%(质量百分含量)的硅添加量使得比容量从2000 mAh·g~(-1)提高到2600 mAh·g~(-1)),降低了锂的沉积/溶解过电势,有利于引导锂离子回到复合微球内部沉积,大大提高了材料的循环稳定性。同时,担载了纳米硅颗粒的锂-碳复合球也继承了锂-碳复合微球循环过程中体积膨胀小,不长枝晶的优点。而且添加的纳米硅颗粒还填充了Li-CNT微球中的孔隙,减少了电解液渗入复合微球内部腐蚀里面的金属锂,进一步提高了材料的库仑效率。以添加10%硅的锂碳复合材料作为负极,与商用磷酸铁锂正极组成全电池,在常规酯类电解液中1C (0.7 mA·cm~(-2))条件下能稳定循环900圈以上,库仑效率为96.7%,大大高于同样条件下测得的Li-CNT复合材料(90.1%)和金属锂片(79.3%)的库仑效率。因此,这种通过简单的熔融浸渍法即可制备的,具有高的比容量和长的循环稳定性的锂硅-碳复合材料具有较大的潜能成为高能量密度电池的负极材料,尤其适用于锂硫、锂氧这种正极不含锂源的电池体系。     

Anode optimization strategies for aqueous zinc-ion batteries

Zinc-ion batteries (ZIBs) have received much research attention due to their advantages of safety, non-toxicity, simple manufacture, and element abundance. Nevertheless, serious problems still remain for their anodes, such as dendrite development, corrosion, passivation, and the parasitic hydrogen evolution reaction due to their unique aqueous electrolyte system constituting the main issues that must be addressed, which are blocking the further advancement of anodes for Zn-ion batteries. Herein, we conduct an in-depth analysis of the problems that exist for the zinc anode, summarize the main failure types and mechanisms of the zinc anode, and review the main modification strategies for the anode from the three aspects of the electrolyte, anode surface, and anode host. Furthermore, we also shed light on further modification and optimization strategies for the zinc anode, which provide directions for the future development of anodes for zinc-ion batteries.

This review provides a comprehensive summary of the research progress of Zn anodes, including the main challenges of Zn metal anodes, the corresponding optimization strategies, and the perspectives for practical aqueous Zn-ion batteries.     

Dendrite‐Free Nanocrystalline Zinc Electrodeposition from an Ionic Liquid Containing Nickel Triflate for Rechargeable Zn‐Based Batteries

Metallic zinc is a promising anode material for rechargeable Zn‐based batteries. However, the dendritic growth of zinc has prevented practical applications. Herein it is demonstrated that dendrite‐free zinc deposits with a nanocrystalline structure can be obtained by using nickel triflate as an additive in a zinc triflate containing ionic liquid. The formation of a thin layer of Zn–Ni alloy (η‐ and γ‐phases) on the surface and in the initial stages of deposition along with the formation of an interfacial layer on the electrode strongly affect the nucleation and growth of zinc. A well‐defined and uniform nanocrystalline zinc deposit with particle sizes of about 25 nm was obtained in the presence of Ni^II. Further, it is shown that the nanocrystalline Zn exhibits a high cycling stability even after 50 deposition/stripping cycles. This strategy of introducing an inorganic metal salt in ionic liquid electrolytes can be considered as an efficient way to obtain dendrite‐free zinc.     

A Sodiophilic Interphase‐Mediated,Dendrite‐Free Anode with Ultrahigh Specific Capacity for Sodium‐Metal Batteries

Despite efforts to stabilize sodium metal anodes and prevent dendrite formation, achieving long cycle life with high areal capacities remains difficult owing to a combination of complex failure modes that involve retardant uneven sodium nucleation and subsequent dendrite formation. Now, a sodiophilic interphase based on oxygen‐functionalized carbon nanotube networks is presented, which concurrently facilitates a homogeneous sodium nucleation and a dendrite‐free, lateral growth behavior upon recurring sodium plating/stripping processes. This sodiophilic interphase renders sodium anodes with an ultrahigh capacity of 1078 mAh g^?1 (areal capacity of 10 mAh cm^?2), approaching the theoretical capacity of 1166 mAh g^?1 of pure sodium, as well as a long cycle life up to 3000 cycles. Implementation of this anode allows for the construction of a sodium–air battery with largely enhanced cycling performance owing to the oxygen functionalization‐mediated, dendrite‐free sodium morphology.     

A Sodiophilic Interphase‐Mediated,Dendrite‐Free Anode with Ultrahigh Specific Capacity for Sodium‐Metal Batteries

Despite efforts to stabilize sodium metal anodes and prevent dendrite formation, achieving long cycle life with high areal capacities remains difficult owing to a combination of complex failure modes that involve retardant uneven sodium nucleation and subsequent dendrite formation. Now, a sodiophilic interphase based on oxygen‐functionalized carbon nanotube networks is presented, which concurrently facilitates a homogeneous sodium nucleation and a dendrite‐free, lateral growth behavior upon recurring sodium plating/stripping processes. This sodiophilic interphase renders sodium anodes with an ultrahigh capacity of 1078 mAh g^?1 (areal capacity of 10 mAh cm^?2), approaching the theoretical capacity of 1166 mAh g^?1 of pure sodium, as well as a long cycle life up to 3000 cycles. Implementation of this anode allows for the construction of a sodium–air battery with largely enhanced cycling performance owing to the oxygen functionalization‐mediated, dendrite‐free sodium morphology.