Search

Lithium (Li) metal, with its unparalleled theoretical capacity and lowest electrochemical potential, is a promising anode material for rechargeable batteries. Yet, challenges such as dendrite formation, severe electrode volume change, and ongoing Li consumption impede its practical adoption. To address these challenges, a novel approach is introduced, harnessing the switchable electrical conductivity of a nanoporous current collector for Li metal anode. A vertically aligned Nickel‐catecholate (VANC) is directly grown on the copper foil as the nanoporous current collector, and the Li intercalation and de‐intercalation of VANC reversibly decrease and increase the electrical conductivity in the direction perpendicular to the electrode, respectively. The switchable conductivity induces uniform deposition and stripping of Li metal without forming dendrite and dead Li during the Li plating/stripping process and thus enables high coulombic efficiency of over 98% even after 200 cycles. This nanoporous structure with switchable conductivity will open up a new path for reliable lithium metal anode for rechargeable battery applications. [ABSTRACT FROM AUTHOR]

Utilization of lithium (Li) metal anode is highly desirable for achieving high energy density batteries. Even so, the unavoidable features of Li dendritic growth and inactive Li are still the main factors that hinder its practical application. During plating and stripping, the solid electrolyte interphase (SEI) layer can provide passivation, playing an important role in preventing direct contact between the electrolyte and the electrode in Li metal batteries. Because of complexities of the electrolyte chemical and electrochemical reactions, the various formation mechanisms for the SEI are still not well understood. What we do know is that a strategic artificial SEI achieved through additives electrolyte can suppress the Li dendrites. Otherwise, the dendrites keep generating an abundance of irreversible Li, resulting in severe capacity loss, internal short‐circuiting, and cell failure. In this minireview, we focus on the phenomenon of dendritic Li‐growth and provide a brief overview of SEI formation. We finally provide some clear insights and perspectives toward practical application of Li metal batteries. [ABSTRACT FROM AUTHOR]

Lithium (Li) metal is regarded as the most attractive anode material for high‐energy Li batteries, but it faces unavoidable challenges—uncontrollable dendritic growth of Li and severe volume changes during Li plating and stripping. Herein, a porous carbon framework (PCF) derived from a metal–organic framework (MOF) is proposed as a dual‐phase Li storage material that enables efficient and reversible Li storage via lithiation and metallization processes. Li is electrochemically stored in the PCF upon charging to 0 V versus Li/Li+ (lithiation), making the PCF surface more lithiophilic, and then the formation of metallic Li phase can be induced spontaneously in the internal nanopores during further charging below 0 V versus Li/Li+ (metallization). Based on thermodynamic calculations and experimental studies, it is shown that atomically dispersed zinc plays an important role in facilitating Li plating and that the reversibility of Li storage is significantly improved by controlled nanostructural engineering of 3D porous nanoarchitectures to promote the uniform formation of Li. Moreover, the MOF‐derived PCF does not suffer from macroscopic volume changes during cycling. This work demonstrates that the nanostructural engineering of porous carbon structures combined with lithiophilic element coordination would be an effective approach for realizing high‐capacity, reversible Li‐metal anodes. [ABSTRACT FROM AUTHOR]

Silicon (Si) is one of the most promising anodes for next-generation lithium (Li)-ion batteries because of its high capacity. However, the commercial uses of Si anodes are hindered by extremely poor cycling stability caused by huge volume expansion during charging and discharging processes as well as by a change in material properties according to Li concentration. Given these reasons, we propose the multiscale analysis of Si nanowire anode using a diffusion-induced stress model with Li concentration effects, such as softening of mechanical modulus and enhancement of Li diffusion. From the geometry context, the diffusion-induced stress model exhibits stress relaxation during the lithiation and optimal condition of the Si nanowire. We then construct an approximated stress criteria equation for the safe operation of Si nanowire of various sizes and shapes. Our multiscale analysis predicts the various types of Si nanowire, including holecaped Si nanowires, which are beneficial to mechanical stability. This study provides insights into the physics of Li-Si compound behaviors and introduces the possibility of developing Si-based anodes with mechanical stability. [ABSTRACT FROM AUTHOR]

This study presents a simple and effective method of reducing amorphous silica (a-SiO2) with Ti metal through high-energy mechanical milling for improving its reactivity when used as an anode material in lithium-ion batteries. Through thermodynamic calculations, it is determined that Ti metal can easily take oxygen atoms from a-SiO2 by forming a thermodynamically stable SiO2− x/TiO x composite, meaning that electrochemically inactive a-SiO2 is partially reduced by the addition of Ti metal powder during milling. This mechanically reduced SiO2− x/TiO x composite anode exhibits a greatly improved electrochemical reactivity, with a reversible capacity of more than 700 mAh g−1 and excellent cycle performance over 100 cycles. Furthermore, an enhancement in the mechanical and thermal stability of the composite during cycling can be mainly attributed to the in situ formation of the SiO2− x/TiO x phase. These findings provide new insight into the rational design of robust, high-capacity, Si-based anode materials, as well as their reaction mechanism. [ABSTRACT FROM AUTHOR]

Keywords: Lithium metal anode; Lithium dendrite growth; Solid-electrolyte interphase (SEI); Electrolyte additives; Anode-free EN Lithium metal anode Lithium dendrite growth Solid-electrolyte interphase (SEI) Electrolyte additives Anode-free 4008 4008 1 12/15/21 20211213 NES 211213 B Lithium metal anode b is highly desirable for high-energy density batteries. Cover Feature: Strategic Approaches to the Dendritic Growth and Interfacial Reaction of Lithium Metal Anode (Chem. Lithium metal anode, Lithium dendrite growth, Solid-electrolyte interphase (SEI), Electrolyte additives, Anode-free. [Extracted from the article]

To meet the growing demand for high-power lithium-ion batteries (LIBs), the development of advanced materials is crucial because they play a central role in energy storage technologies. Although graphite is widely used as the most popular anode material, the rate capability and thermal stability of graphite should be further improved for extending the applications of LIBs into emerging markets like electric vehicles and personal mobility devices. With this in mind, we propose off-stoichiometric TiO 2- x -decorated graphite as a potential anode material for practical use in high-power LIBs. Thanks to the high electrical conductivity and thermal resistance of off-stoichiometric TiO 2- x induced by an in situ carbothermal reduction process, the rate capability and thermal stability of graphite can be notably enhanced. The TiO 2- x -decorated graphite offers a high capacity retention of 76.9% even after 100 cycles at a current density of 1C. We believe that this work can provide more opportunities to explore highly reliable anode materials offering high-energy and high-power characteristics for advanced LIBs. A TiO 2-x -decorated graphite is synthesized via an in situ carbon thermal reduction process and its feasibility is thoroughly examined as a potential anode material for practical use in high-power LIBs. The high electrical conductivity and thermal resistance of off-stoichiometric TiO 2-x decorated on the surface of graphite allow the improvement of rate capability and thermal stability of graphite anode. Image 1 • A TiO 2-x -decorated graphite is synthesized via an in situ carbon thermal reduction process as an anode material for LIBs. • The decoration of TiO 2-x nanoparticles is beneficial for improving the rate capability and thermal stability of graphite. • A TiO 2-x -decorated graphite offers a stable cycle performance up to 100 cycle at a current density of 1C. [ABSTRACT FROM AUTHOR]

[Display omitted] • Defect in graphene-silicon(d-Gr/Si) composites enhances electrochemical performance. • Li adsorption energies in the d-Gr/Si were less than -0.6 eV and 0.25 eV at pristine Gr/Si. • Defected Gr/Si is more thermionically stable than pristine Gr/Si. • Charge transfer on defects improves electrical conduction and mechanical strength at interfaces. • Our analyses elucidate that defect engineering enhances Li capacity and mechanical strength. Carbon-coated silicon materials are considered as promising anode materials in high-capacity lithium-ion batteries (LIBs). Theoretically, using graphene as the anode material in the LIB would afford high electrical conductivity, mechanical stability of Si, and suppression of the unstable solid–electrolyte interface. However, its usage is hindered by its electrochemical characteristic, which is not electrochemically active when combined with lithium. Therefore, research on graphene as the anode and coated material in LIBs has been conducted using defect engineering to enhance the storage capacity of graphene. Although the electrochemical characteristics of various defects in graphene have been studied experimentally and theoretically, graphene-based composite anode materials such as graphene–silicon composite electrodes have rarely been studied from the electrochemical and mechanical perspectives. In this study, lithium adsorptions are conducted on various defected graphene and graphene–silicon composites using density functional theory calculation. The formation energies of Li on the various defected graphene are assessed, and the mechanical strengths of the graphene–silicon composites are analyzed. Our calculations validate that the defects in graphene enhance the electrochemical adsorptions and interfacial mechanical strengths of the graphene and graphene–silicon composites. During lithiation, the defects mediate greater interfacial adhesion of the silicon–graphene composite. Hence, we elucidate that defected graphene increases the electro-chemo mechanical stabilities of silicon composites in high-capacity LIBs. [ABSTRACT FROM AUTHOR]