Suppress Dendrite Formation Research Articles

Argyrodite-Li6PS5Cl/Polymer-based Highly Conductive Composite Electrolyte for All-Solid-State Batteries.

Solid-state batteries (SSBs) that incorporate the argyrodite-Li6PS5Cl (LPSCl) electrolyte hold potential as substitutes for conventional lithium-ion batteries (LIBs). However, the mismatched interface between the LPSCl electrolyte and electrodes leads to increased interfacial resistance and the rapid growth of lithium (Li) dendrites. These factors significantly impede the feasibility of their widespread industrial application. In this study, we developed a composite electrolyte of the LPSCl/polymer to enhance the contact between the electrolyte and electrodes and suppress dendrite formation at the grain boundary of the LPSCl ceramic. The monomer, triethylene glycol dimethacrylate (TEGDMA), is utilized for in situ polymerization through thermal curing to create the argyrodite LPSCl/polymer composite electrolyte. Additionally, the ball-milling technique was employed to modify the morphology and particle size of the LPSCl ceramic. The ball-milled LPSCl/polymer composite electrolyte demonstrates slightly higher ionic conductivity (ca. 2.21 × 10-4 S/cm) compared to the as-received LPSCl/polymer composite electrolyte (ca. 1.65 × 10-4 S/cm) at 25 °C. Furthermore, both composite electrolytes exhibit excellent compatibility with Li-metal and display cycling stability for up to 1000 h (375 cycles), whereas the as-received LPSCl and ball-milled LPSCl electrolytes maintain stability for up to 600 h (225 cycles) at a current density of 0.4 mA/cm2. The SSB with the ball-milled LPSCl/polymer composite electrolyte delivers high specific discharge capacity (138 mA h/g), Coulombic efficiency (99.97%), and better capacity retention at 0.1C, utilizing the battery configuration of coated NMC811//electrolyte//Li-Indium (In) at 25 °C.

Deciphering the effect of nucleation/growth kinetics on the morphology of Li plating/stripping on vertically aligned carbon nanofibers - A low-tortuosity 3-D nanostructured carbon host

Reversible lithium metal anodes (LMAs) are the holy grail for future rechargeable lithium metal batteries. Three-dimensional (3-D) conductive hosts have been extensively explored as an effective approach to suppressing dendrite formation and enabling reversible Li plating/stripping. However, the microscopic morphologies of Li plating and their correlation with the cell performance are not clear. Herein we unravel these issues using the vertically aligned carbon nanofiber (VACNF) array as a model 3-D conductive carbon host which has a well-defined vertical low-tortuosity structure allowing observation of the intrinsic Li morphologies infiltrated into the 3-D host. The VACNF array indeed provides much higher stability and reversibility for Li plating/stripping due to its high surface area and lithiophilic properties. We found that Li plating on both VACNF array and planar Cu electrodes follows the classical nucleation and growth model. Though the low plating current density (≤0.10 mA/cm2) provides better cycling stability consistent with the Sand’s equation, it forms sparse irregular grains stacked with dendrite-like long Li fibers. In contrast, the moderate to high plating current densities (1.0 − 5.0 mA/cm2) produce more uniform Li morphologies consisting of smaller micro-columns or micro-spheres. By decoupling the plating and stripping current densities, we unravel that the more uniform micro-columnar Li infiltrated in the VACNF array obtained at the moderate plating current density (∼1.0 mA/cm2) indeed exhibits the highest cycling performance. This provides new insights into the relationship between macroscopic electrochemical tests and microscopic Li morphologies, aiding in optimizing the performance of LMAs based on 3-D conductive hosts.

Molecular Structure Engineering of Isomeric Additives for Long Lifetime Zn Anodes.

Modulating the solvation structure of hydrated zinc ions using organic additives stands as a pragmatic approach to suppress dendrite formation and corrosion on zinc metal anodes (ZMAs), thereby enhancing the rechargeability of aqueous Zn-ion batteries. However, fundamental screening principles for organic additives with diverse molecular structures remain elusive, especially for isomers with the same molecular formula. This study delves into the impact of three isomeric hexagonal alcohols (mannitol, sorbitol, and galactitol) as additives in adjusting Zn2+ solvation structural behaviors within ZnSO4 baseline electrolytes. Electrical measurements and molecular simulations reveal the specific molecular structure of mannitol, which features interweaving electron clouds between adjacent hydroxyl groups, achieving a high local electron cloud density. This phenomenon significantly enhances desolvation abilities, thus establishing a more stable anode/electrolyte interface chemistry. Even at 5mA cm-2 for 2.5 mAh cm-2 capacity, Zn||Zn symmetric cells with mannitol-regulated electrolyte display an impressive 1170 h lifespan, far exceeding those with other isomer additives and is nearly tenfold longer than that with a pure ZnSO4 electrolyte (120 h). Rather than strictly adhering to focusing on chemical composition, this study with emphasison optimizing molecular structure offers a promising untapped dimension to screen more efficient additives to enhance the reversibility of ZMAs.

Aqueous Zinc Metal Batteries with Anode Stabilized by Plasma Treatment

Aqueous Zn batteries have recently attracted significant attention due to the various benefits offered by Zn metal anodes. However, the formation of dendrites and unwanted side reactions between the Zn anode and the aqueous electrolyte remain challenging problems. Herein, a straightforward plasma treatment that converts the surface of the Zn metal into ZnF2 is proposed. Calculations using density function theory reveal that the diffusion energy barrier for Zn atoms on the ZnF2 surface (0.02 eV) is considerably lower than that on the regular Zn surface (0.25 eV). As a result, the Zn anode treated with plasma (referred to as Plasma‐Zn) exhibits a highly reversible Zn plating/stripping process and significantly suppresses dendrite formation for more than 1300 h. Furthermore, when combined with polyaniline (PANi)‐intercalated V2O5 in a full cell configuration (Plasma‐Zn//PANi‐intercalated V2O5), it demonstrates enhanced rate capability, delivering a discharge capacity of 258 mAh g−1 at 2000 mA g−1, along with improved long‐term stability, retaining 72% of its capacity after 1000 cycles at 1000 mA g−1.

Synergistic Interfacial Optimization for High-Sulfur-Content All-Solid-State Lithium-Sulfur Batteries.

Improving the sulfur content in the cathode is essential for achieving high-energy-density all-solid-state lithium-sulfur batteries (ASSLSBs). However, the complex multiinterfaces, akin to the short wooden planks that consist of the cask, severely limit the performance of ASSLSBs with high sulfur content. Since singular approaches fail to optimize these interfaces simultaneously, we propose a synergistic approach using a dual-doped sulfide solid electrolyte (Y2S3 and LiI) and an SbSn alloy sulfur host in this work. The incorporation of Y2S3 in the solid electrolyte serves to improve the electrolyte-electrolyte interfaces and enhance the ionic conductivity, while the inclusion of LiI helps stabilize the electrolyte-anode interface and suppress dendrite formation. Meanwhile, the SbSn alloy sulfur host facilitates the transfer of Li+ at the electrolyte-cathode interfaces. Consequently, the solid-solid interfaces are significantly improved, leading to impressive specific capacities in ASSLSBs with high sulfur content (>44% in the cathode composite) at room temperature (1163.5 mAh g-1) and at 60 °C (1408.7 mAh g-1) during the 50th cycle at 0.05C. This work presents a promising strategy for achieving practical high-performance ASSLSBs.

Zincophilic Sn sites induced the local ion enrichment for compact and homogenous growth of Zn biscuits in long-life Zn metal batteries

A self-supporting substrate (reduced copper foam with thin Sn decoration layer, R-CF@Sn) is prepared by a pre-oxidation and electroless plating process to achieve uniform Zn deposition and suppress dendrite formation.

Bifunctional interface stabilizer for promoting preferential crystal face adsorption and inducing planar Zn growth

A unique kind of organic small molecules with two zincophilic sites is demonstrated as the bifunctional interface stabilizer (BIS) for promoting uniform Zn deposition and suppressing dendrite formation.

High Zn(002)-preferential orientation enabled by a proton additive for dendrite-free zinc anodes

A zinc anode with high Zn(002)-preferential orientation can be achieved using a universal proton additive, which has been shown to effectively suppress dendrite formation in aqueous zinc batteries.

Ab Initio Molecular Dynamics Study on Self-Healing Solid Polymer Electrolyte for Lithium Metal Batteries

Lithium metal batteries (LMBs) have generally become potential candidates for energy storage devices because of their high energy density. However, the practical applications of LMBs have been limited due to the low safety of liquid electrolytes. Compared to liquid electrolytes, solid-state polymer electrolytes (SPEs) have excellent mechanical strength. However, there is room for improvement because traditional PEO-based SPEs need more mechanical properties and electrode contacts for flexible energy device applications. Self-healing solid polymer electrolytes (SHSPEs) have excellent flexibility and healing ability and can also suppress dendrite formation to increase the safety of LMBs. In this study, a novel SHSPE is designed by a combination of the zwitterionic copolymer, SBMA ([2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide)-co-BA (Butyl Acrylate), and a lithium salt, LiTFSI. We explored their solvation structures and reactivity on the Li metal anode using Density functional theory (DFT) and ab initio molecular dynamics (AIMD) methods. Besides, we also studied the reactivity of the considered SHSPE on the Cu (100) surface to explore the SEI formation mechanisms. The cationic NR4 + and anionic SO3 - groups of SBMA interact electrostatically and form cross-linked network structures within the electrolyte framework, providing the designed SHSPE with prominent self-healing capacity. The decomposition reactions of SHSPE on the Li metal anode are explored, and the resultant decomposition products that contribute to the formation of the solid electrolyte interphase (SEI) are identified. Furthermore, AIMD results indicate that highly concentrated SO3 - groups in the SHSPE promote Li ion diffusion, which increases Li ionic conductivity. The present findings provide design criteria for developing highly conductive self-healing SPEs.

Surface Modification of Li Metal Anodes Using Ag Nanoparticles and PVDF: An EC-AFM Investigation

Lithium metal has captured interest as an attractive anode material for next-generation batteries due to its extremely large theoretical specific capacity (approximately 3800 mAh/g) and low reduction potential. However, challenges related to uncontrolled lithium plating and stripping, unwanted side reactions, and uneven lithium growth on the surface (top growth) contribute to safety concerns and poor cycling performance, hindering the widespread application of lithium metal batteries [1]. In this study, we conducted electrochemical atomic force microscopy (EC-AFM) to investigate the lithium deposition behavior of silver nanoparticles (Ag NPs) on lithium metal substrate surfaces. Kelvin probe force microscopy (KPFM) revealed that Ag NPs possess a lower surface potential than the lithium substrate surface, providing reaction sites for lithium deposition during the plating process. This leads to the formation of a lithium-silver (LiAg) solid solution instead of pure lithium metal, effectively mitigating the issues associated with uncontrolled Li plating. The LiAg alloy phase exhibited improved reversibility compared to bare lithium metal, resulting in improved cycling performance [2]. Additionally, we found that coating the lithium metal surface with a layer of polyvinylidene fluoride (PVDF) promotes bottom-up lithium deposition while physically suppressing dendrite formation. As an ionically conductive but electronically resistant polymer, PVDF allows Li+ transport while suppressing lithium deposition on the top surface [3], reducing safety issues associated with dendrite formation during lithium deposition. Our EC-AFM results reveal the morphological evolution of Ag NPs and PVDF on lithium metal during the plating and stripping process, offering preliminary insights into the underlying mechanisms. Based on our investigations, we propose that the combination of Ag NPs and PVDF could potentially be an effective choice for modifying lithium metal surfaces. This approach aims to enable controlled lithium plating and stripping, as well as bottom-up lithium deposition, with the goal of improving safety and cycling performance for anodes in the next generation of high-energy-density lithium metal batteries, focusing on improving safety and achieving long life cycle.[1] H. Park et al, Adv. Energy Mater. 2021, 11, 2003039.[2] S. Jin et al, J. Am. Chem. Soc. 2020, 19, 8818.[3] J. Yun et al, ACS Energy Lett. 2020, 5, 3108.

Diagnosing the Electrostatic Shielding Mechanism for Dendrite Suppression in Aqueous Zinc Batteries.

Aqueous zinc electrolytes offer the potential for cheaper rechargeable batteries due to their safe compatibility with the high capacity metal anode; yet, they are stymied by irregular zinc deposition and consequent dendrite growth. Suppressing dendrite formation by tailoring the electrolyte is a proven approach from lithium batteries; yet, the underlying mechanistic understanding that guides such tailoring does not necessarily directly translate from one system to the other. Here, it is shown that the electrostatic shielding mechanism, a fundamental concept in electrolyte engineering for stable metal anodes, has different consequences for the plating morphology in aqueous zinc batteries. Operando electrochemical transmission electron microscopy is used to directly observe the zinc nucleation and growth under different electrolyte compositions and reveal that electrostatic shielding additive suppresses dendrites by inhibiting secondary zinc nucleation along the (100) edges of existing primary deposits and encouraging preferential deposition on the (002) faces, leading to a dense and block-like zinc morphology. The strong influence of the crystallography of Zn on the electrostatic shielding mechanism is further confirmed with Zn||Ti cells and density functional theory modeling. This work demonstrates the importance of considering the unique aspects of the aqueous zinc battery system when using concepts from other battery chemistries.

Recent developments in three‐dimensional Zn metal anodes for battery applications

AbstractAqueous zinc (Zn) ion batteries (AZIBs) are regarded as one of the promising candidates for next‐generation electrochemical energy storage systems due to their low cost, high safety, and environmental friendliness. However, the commercialization of AZIBs has been severely restricted by the growth of dendrite at the Zn metal anode. Tailoring the planar‐structured Zn anodes into three‐dimensional (3D) structures has proven to be an effective way to modulate the plating/stripping behavior of Zn anodes, resulting in the suppression of dendrite formation. This review provides an up‐to‐date review of 3D structured Zn metal anodes, including working principles, design, current status, and future prospects. We aim to give the readers a comprehensive understanding of 3D‐structured Zn anodes and their effective usage to enhance AZIB performance.

High dielectric filler for all-solid-state lithium metal battery

Lithium metal with its high theoretical capacity and low negative potential is considered one of the most important candidates to raise the energy density of all-solid-state batteries. However, lithium filament growth and its induced solid electrolyte decomposition pose severe challenges to realize a long cycle life. Here, dendrite growth in solid-state Li metal batteries is alleviated by introducing a high dielectric material, barium titanate, as a filler that removes the electric field gradients that catalyze dendrite formation. In symmetrical Li-metal cells, this results in a very small over-potential of only 48 mV at a relatively high current density of 1 mA cm−2, when cycling a capacity of 2 mA h cm−2 during 1700 h. The high dielectric filler improves the Coulombic efficiency and cycle life of full cells and suppresses electrolyte decomposition as indicated by solid-state nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) measurements. This indicates that the high dielectric filler can suppress dendrite formation, thereby reducing solid electrolyte decomposition reactions, resulting in the observed low overpotentials and improved cycling efficiency.

In Vitro Study of the Effects of Five Chemically Modified Tetracycline (CMT) Analogs on Human Epidermal Melanogenesis: Potential as Novel Anti-Melanogenic Agents

Treatment of hyperpigmented skin disorders by novel drug candidates without side effects remains an ongoing area of research. Chemically modified tetracyclines (CMTs) are a group of nonantimicrobial tetracycline drugs that have been shown to possess multiple pharmacological activities. We have previously documented the anti-melanogenic effects of CMT-3 and its 9-amino derivative, CMT-308. Herein, we have extended our analysis to evaluate other CMT analogs, namely CMT-1, CMT-4, CMT-5, CMT-6, and CMT-8, for their impact on melanogenesis using primary human epidermal melanocytes (HEMn-DP cells). CMT analogs were screened using a tetrazolium-based assay to identify nontoxic concentration ranges that were further used to analyze the effects of CMTs on cellular melanin content and morphology (via quantitation of dendricity). Cellular tyrosinase (TYR) activity and levels of melanogenesis proteins, TYR, and microphthalmia transcription factor (MITF) were also evaluated to elucidate the mechanisms underlying their effects on melanogenesis. The findings demonstrated that exposure to CMT-8 resulted in notable cytotoxic effects at concentrations >10 µM; hence, all five analogs were further evaluated and compared at 10 µM. None of the five CMT analogs exhibited any impact on intracellular melanin in HEMn-DP cells at the concentration of 10 µM. However, CMT-1, CMT-4, and CMT-8 robustly suppressed dendricity parameters in HEMn-DP cells, while CMT-5 and CMT-6 showed no effect, suggesting that only a subset of CMT analogs can attenuate melanocyte dendricity. Moreover, the analog CMT-5, which has β-diketone blocked, was ineffective, thus confirming the role of this moiety in suppressing dendrite formation. CMT-1 and CMT-8 did not affect cellular tyrosinase activity, while CMT-4 suppressed TYR activity at 10 µM. The capacity of CMT-4 and CMT-8 to suppress dendricity was partly associated with their ability to downregulate MITF protein levels, while CMT-1 had no effect on MITF but suppressed TYR protein levels. The results of this study indicate that CMT-1, CMT-4, and CMT-8 merit further investigation using in vivo studies as potential drug candidates for the treatment of hyperpigmentation disorders.

An ultrathin natural cellulose based hydrogel membrane for the high-performance quasi-solid-state zinc-ion batteries

Aqueous zinc-ion batteries (ZIBs) are regarded as promising candidates for next-generation energy storage systems due to their high capacity, inherent safety, and cost-effectiveness. However, the practical application of ZIBs is currently hindered by the insufficient stability of the zinc metal electrode and the spontaneous growth of dendrites during operation. Furthermore, the use of petroleum-based materials in batteries raises environmental concerns that must be addressed. This study proposes a natural cellulose-based biodegradable hydrogel membrane with an ultrathin and non-porous structure. Paper scraps are utilized as raw materials, and DMAc/LiCl serves as the dissolution system. The quasi-solid cellulose membrane demonstrates a high liquid absorption ability, favorable mechanical properties (39.5 MPa), excellent ion conductivity (0.643 mS cm−1), a wide electrochemical window (1.6 V), and a low activation energy for Zn2+ conduction (3.195 kJ mol−1). The Zn//Zn symmetric battery, assembled with the cellulose membrane, exhibits prolonged reversible Zn2+ stripping/plating behavior (up to 1800 h at 1 mA cm−2), highlighting its superior capability to suppress dendrite formation. Additionally, the corresponding Zn//V2O5 battery shows enhanced electrochemical stability, long cycle life, and high capacity. This research provides valuable insights for the development of polymer electrolytes that enable the realization of safe, lightweight, and environmentally friendly aqueous ZIBs.

Bifunctional K3PW12O40/Graphene Oxide-Modified Separator for Inhibiting Polysulfide Diffusion and Stabilizing Lithium Anode.

Lithium-sulfur (Li-S) batteries are considered as promising candidates for next-generation batteries due to their high theoretical energy density. However, the practical application of Li-S batteries is still hindered by several challenges, such as the polysulfide shuttle and the growth of lithium dendrites. Herein, we introduce a bifunctional K3PW12O40/graphene oxide-modified polypropylene separator (KPW/GO/PP) as a highly effective solution for mitigating polysulfide diffusion and protecting the lithium anode in Li-S batteries. By incorporating KPW into a densely stacked nanostructured graphene oxide (GO) barrier membrane, we synergistically capture and rapidly convert lithium polysulfides (LiPSs) electrochemically, thus effectively suppressing the shuttling effect. Moreover, the KPW/GO/PP separator can stabilize the lithium metal anode during cycling, suppress dendrite formation, and ensure a smooth and dense lithium metal surface, owing to regulated Li+ flux and uniform Li nucleation. Consequently, the constructed KPW/GO/PP separator delivered a favorable initial specific capacity (1006 mAh g-1) and remarkable cycling performance at 1.0 C (626 mAh g-1 for up to 500 cycles with a decay rate of 0.075% per cycle).

Encapsulating lithium at the microscale: selective deposition in carbon-doped graphitic carbon nitride spheres.

For stable lithium deposition without dendrites, three-dimensional (3D) porous structure has been intensively investigated. Here, we report the use of carbon-doped graphitic carbon nitride (C-doped g-C3N4) microspheres as a 3D host for lithium to suppress dendrite formation, which is crucial for stable lithium deposition. The C-doped g-C3N4 microspheres have a high surface area and porosity, allowing for efficient lithium accommodation with high accessibility. The carbon-doping of the g-C3N4 microspheres confers lithiophilic properties, which facilitate the regulation of Li+ flux and dense filling of cavities with nucleated lithium, thereby preventing volume expansion and promoting dendrite-free Li deposition. The electrochemical performance was improved with cyclic stability and high Coulombic efficiency over 260 cycles at 1.0 mA cm-2 for 1.0 mA h cm-2, and even over 70 cycles at 5.0 mA cm-2 for 3.0 mA h cm-2. The use of C-doped g-C3N4 microspheres as a 3D Li host shows promising results for stable lithium deposition without dendrite formation.&#xD.

Regulating Zinc Deposition via Zincophilic 2D‐Cu2Te as the Current Collector to Suppress Dendrite Formation toward High Performance Aqueous Zinc‐Ion Batteries

AbstractInvited for this month's cover is the group of Nano Horizons Lab hosted by Prof. Yu‐Ze Chen. The cover picture shows the lateral deposition of Zn guided by zincophilic Cu2Te flakes, resulting in the suppression of dendrite growth. Read the full text of the Research Article at 10.1002/batt.202300107.

Polyolefin‐Based Separator with Interfacial Chemistry Regulation for Robust Potassium Metal Batteries

AbstractPotassium metal batteries (KMBs) are ideal choices for high energy density storage system owing to the low electrochemical potential and low cost of K. However, the practical KMB applications suffer from intrinsically active K anode, which would bring serious safety concerns due to easier generation of dendrites. Herein, to explore a facile approach to tackle this issue, we propose to regulate K plating/stripping via interfacial chemistry engineering of commercial polyolefin‐based separator using multiple functional units integrated in tailored metal organic framework. As a case study, the functional units of MIL‐101(Cr) offer high elastic modulus, facilitate the dissociation of potassium salt, improve the K+ transfer number and homogenize the K+ flux at the electrode/electrolyte interface. Benefiting from these favorable features, uniform and stable K plating/stripping is realized with the regulated separator. Full battery assembled with the regulated separator showed ∼19.9 % higher discharge capacity than that with glass fiber separator at 20 mA g−1 and much better cycling stability at high rates. The generality of our approach is validated with KMBs using different cathodes and electrolytes. We envision that the strategy to suppress dendrite formation by commercial separator surface engineering using tailor‐designed functional units can be extended to other metal/metal ion batteries.

A Gradient Lithiophilic Structure for Stable Lithium Metal Anodes with Ultrahigh Rate and Ultradeep Capacity.

Using three-dimensional current collectors (3DCC) as frameworks for lithium metal anodes (LMAs) is a promising approach to inhibit dendrite growth. However, the intrinsically accumulated current density on the top surface and limited Li-ion transfer in the interior of 3DCC still lead to the formation of lithium dendrites, which can pose safety risks. In this study, it reports that gradient lithiophilic structures can induce uniform lithium deposition within the interior of the 3DCC, greatly suppressing dendrite formation, as confirmed by COMSOL simulations and experimental results. With this concept, a gradient-structured zinc oxide-loaded copper foam (GSZO-CF) is synthesized via an easy solution-combustion method at low cost. The resulting Li@GSZO-CF symmetric cells demonstrate stable cycling performance for over 800 cycles, with an ultra-deep capacity of 10 mAh cm-2 even under an ultra-high current density of 50mA cm-2 , the top results reported in the literature. Moreover, when combined with a LiFePO4 (LFP) cathode under a low negative/positive (N/P) capacity ratio of 2.9, the Li@GSZO-CF||LFP full cells exhibit stable performance for 200 cycles, with a discharge capacity of 130 mAh g-1 and retention of 85.5% at a charging/discharging rate of 1C. These findings suggest a promising strategy for the development of new-generation LMAs.