Stable Cycle Life Research Articles

Enhanced Electrochemical Performance of Dual-Ion Batteries with T-Nb2O5/Nitrogen-Doped Three-Dimensional Porous Carbon Composites

Niobium pentoxide (T-Nb2O5) is a promising anode material for dual-ion batteries due to its high lithium capacity and fast ion storage and release mechanism. However, T-Nb2O5 suffers from the disadvantages of poor electrical conductivity and fast cycling capacity decay. Herein, a nitrogen-doped three-dimensional porous carbon (RMF) was prepared for loading niobium pentoxide to construct a composite system with excellent electrochemical performance. The obtained T-Nb2O5/RMF composites have a well-developed pore structure and a high specific surface area of 1568.5 m2 g−1, which could effectively increase the contact area between the material and electrolyte, improving the electrode reaction and lithium-ion transfer diffusion. Nitrogen doping increased surface polarity, creating more active sites and accelerating the electrode reaction rate. The introduction of T-Nb2O5 imparted high power density and excellent cycling stability to the battery. The composites exhibited good electrochemical performance when used as dual-ion battery anode, with a stable cycle life of 207.2 mA h g−1 at 1 A g−1 current density after 650 cycles and great rate performance of 181.5 mA h g−1 at 5A g−1 was also obtained. This work provides the possibility for applying T-Nb2O5/RMF as an anode for a high-performance dual-ion battery.

Regulating Zn deposition via an ion-sieving, nanoporous cellulose separator for high performance aqueous zinc-ion batteries.

Aqueous zinc-ion batteries (AZIBs), one of the most promising renewable energy storage devices, are largely impeded by the disreputable cycling stability in its large-scale application as a result of the undesirable Zn dendrites growth and the side reactions. In this context, a carboxylate (-COO-) anionic group functionalized cellulose nanofibrils separator (A-CNF) with nanoporous structure and ion-sieving effect is developed to realize a stable Zn anode without dendrites and by-products. An increased Zn2+ transference number and uniform Zn deposition can be achieved through the electrostatic adsorption between -COO- and Zn2+. More importantly, the synergistic effect between -COO- and hydroxyl group (-OH) in the cellulose nanofibrils separator inhibits the occurrence of side reactions caused by SO42- and free water molecules. As a result, the nanoporous separator consisting of carboxylated cellulose nanofibrils enables Zn anode with high stability and utilization, exhibiting a stable cycling life for 950 h in Zn//Zn cell and an admirable coulombic efficiency of 98.9 % after 300 cycles in Zn//Cu cell. The assembled Zn//MnO2 full cell with the nanoporous cellulose nanofibrils-based separator shows exceptional cyclability and capacity retention after 1000 cycles. This work provides a valuable and practical separator for high performance AZIBs, which might spur its practical application.

Effective Electrolyte Combination Composed of 1,1‐Diethoxyethane and Lithium Bis(fluorosulfonyl)imide for Dendrite‐suppressible Li Metal Anodes

AbstractAlthough Li metal is considered the most promising anode material owing to its high theoretical capacity, there are numerous restrictions on expanding its application because of undesired surface reactions occurring at the Li anode. To solve this, an effective electrolyte combination consisting of 1,1‐diethoxyethane (DEE) and lithium bis(fluorosulfonyl)imide (LiFSI) is used in this work, which can provide an organic/inorganic‐hybridized solid‐electrolyte interphase (SEI) at the Li anode. The DEE solvent affords flexible carbon‐abundant components, whereas LiFSI offers mechanically rigid lithium fluoride‐type components; these undergo electrochemical reduction to form SEI layers that are balanced in terms of organic and inorganic components. Systematic analysis results exhibit that when the SEI layer integrated with DEE and LiFSI is embedded in the lithium anode, electrolyte decomposition, and dendritic lithium growth are suppressed in Li/Li cells, thereby improving surface stability. Similarly, it provides stable cycle life characteristics even at 150 cycles in Li/S cells (72.0% vs 52.6%).

Probing the Influence of Steric Hindrance in Nonfluorinated Ether Electrolytes for Lithium Metal Batteries

Abstract Lithium metal batteries (LMBs), especially anode free LMBs, promise much higher energy density than current lithium-ion batteries but suffer from poor capacity retention. While novel electrolytes have been designed to extend cycle life in anode free LMBs, most of them contain a high fraction of fluorinated solvents or diluents that can cause environmental concerns. Herein, we report the design and synthesis of a group of nonfluorinated ether solvents (termed xME solvents). By substituting the methyl terminal group of 1,2-dimethoxy ethane (DME) with different alkyl groups, the solvation power of xME solvents was tuned to be weaker, leading to more ion pairing in electrolyte solvation structure. In anode free type Cu/LiFePO4 (Cu/LFP) cells, xME electrolytes in general show better capacity retention than DME electrolyte. Some xME electrolytes also show better oxidative stability than DME against aluminum and LiNi0.1Mn0.1Co0.8O2 (NMC811) electrodes. While the general improvement in LMB cycle life and oxidative stability can be attributed to more ion pairing, the local variation within xME electrolytes indicates other factors are also important. Our work proposes a molecular design strategy to fine-tune ion solvation structure of nonfluorinated ether electrolytes for LMBs.

Highly Stable Anode-Free Lithium Metal Batteries Via Effective SEI Layer Formation with Lithiophilic Silver Nanoparticle

Lithium metal batteries (LMBs) have garnered attention due to their high specific capacity and low reduction potential. On the other hand, their practical application is limited by persistent safety issues related to Li dendrite growth. Thus LMBs are developing into an anode-free configuration to achieve suppression of dendrite formation and much higher volumetric energy density. However, the intrinsic lithiophobicity of current collectors in anode-free batteries causes to non-uniform Li plating, which still results in unfavorable Li dendritic growth during the charge/discharge cycles. Herein, we have modified the current collector by attaching a bi-functional ligand 2,3,5,6-Tetrafluoro-4-mercaptobenzoic acid (F-MB) to deposit lithiophilic silver nanoparticles (Ag NPs) for the uniform Li nucleation and growth. Therefore, we synthesized fluorine-functionalized lithiophilic Ag-F-MB to form the stable solid-electrolyte interface (SEI) layer. Consequently, Ag-F-MB@Cu||Li half-cell demonstrates a more stable reversibility of coulombic efficiency (~94%) and a longer cycle stability over 1000 hours, attributed to enhanced reversible Li plating/stripping. Additionally, the prelithiated Ag-F-MB@Li||LiFePO4 full-cell exhibits a high initial specific capacity of 162.9 mAh/g, stable cycle life over 1000 hours, and high coulombic efficiency at 1 C. This approach provides a promising method to achieve high-performance LMBs via simple modification of the Cu current collector.

Insights into Crystallography and Electrochemical Performance of Doped Li-Rich Layered Oxides for Lithium-Ion Batteries

The development of new materials is imperative to meet the growing demand for systems delivering higher capacity, energy density, cycle life stability, and safety. Lithium-Rich Layered Oxides (LRLOs) are at the forefront of enabling high-capacity and high energy density positive electrodes for Lithium-Ion Batteries, addressing the challenges of green and safe transportation and sustainable stationary energy storage from renewable sources [1]. LRLOs, with the general formula Li1+xTM1-xO2 (where TM represents a blend of transition metals such as Mn, Co, Ni...), belong to the layered material family but their crystal structure remains elusive [2]. On the other hand, they exhibit excellent reversible performance in aprotic lithium-metal and lithium-ion batteries over numerous charge/discharge cycles. Their higher specific capacity compared to commercial cathodes can be attributed to cumulative cationic and anionic redox processes, wherein anionic redox reactions involve lattice oxygen, balancing lithium extraction with the activation of the O2-/O- redox couple. However, inadequate cycle life stability and capacity retention hinder their commercial adoption, owing to structural rearrangements and phase transitions upon cycling. Moreover, reducing costs and toxicity of raw materials such as cobalt is crucial for large-scale production [3].In this communication, we elucidate the significant influence of extensive defectivity on the description of LRLOs crystal structure. Specifically, we illustrate how the utilization of supercells or defects (antisite defects, stacking faults ...) contribute to a more accurate structural description. Additionally, doping strategies were used to enhance the electrochemical behavior and mitigate the structural rearrangements. Our findings showcase optimized layered materials boasting exceptional electrochemical performance, enhanced environmental compatibility, and reduced manufacturing costs relative to the current state-of-the-art.

Study on Doping Strategies to Improve the Stability of Ni-Rich Layered Cathodes for Electric Vehicles

Lithium-ion batteries (LIBs) with layered-type cathodes, particularly Li[NixCoyMn(1-x-y)]O2 (NCM) and Li[NixCoyAl(1-x-y)]O2 (NCA), are considered frontrunners for powering next-generation electric vehicles (EVs) due to their high energy density potential. However, a critical challenge lies in achieving this potential – increasing the nickel (Ni) content (x>6) in these cathodes leads to decreased cycling lifetimes and lower thermal stabilities, hindering their widespread use. Researchers are actively exploring the strategy of doping transition metals (Al, Mg, Ti, W, etc.) into Ni-rich layered cathodes to enhance their stability [1]. These efforts can be broadly categorized based on the stage at which the dopant is introduced: Dopant addition during precursor co-precipitation. This approach involves incorporating the dopant element alongside the precursor cathode active material during the initial synthesis step. Here, the dopant ions are believed to integrate into the crystal lattice, potentially modifying the material's structure and influencing its electrochemical performance.Dopant addition during calcination step. In this method, the dopant is introduced after the precursor is formed, typically during the high-temperature calcination process. The dopant may coat the cathode secondary particle surface or interact with the lattice at grain boundaries, potentially improving structural stability and mitigating performance degradation. By comprehensively investigating these two primary doping strategies, we aim to optimize the stability of Ni-rich layered cathodes, paving the way for their successful application in high-performance EV batteries. Herein we determine the optimal doping path to achieve the best balance between energy density, cycling life, and thermal stability for next-generation EVs. Acknowledgements This research was funded by the project АР13068160 “Development of the high energy cathode materials for Electric Vehicle application using domestic raw materials from local silicate nickel ore” from the Ministry of Science and Higher Education of the Republic of Kazakhstan.

Correlation between Lithium Titanate Powder Morphology and High Rate Performance in Lithium-Ion Batteries

Among the various intercalation and insertion materials, lithium titanium oxide (Li4Ti5O12, LTO) is considered a safe, “zero-strain” compound, since its volume changes are less than 1% during the lithium insertion/extraction processes [1]. This results in better cycle life and higher structural stability than graphite and other materials that suffer from much higher volume changes [2-5].The major disadvantage of lithium titanium oxide is its poor electrical conductivity (<10−13 S cm−1) [6]. Several attempts have been made to further improve the performance of Li4Ti5O12, including doping, coating, particle engineering, or the modification of synthesis procedures. Some of these approaches produce materials with improved capacity retention at high C-rates; however, many are expensive or relatively slow, and thus unfavorable for commercial application.The primary objective of this study was to shed light on the essential factor responsible for the superior performance of LTO powders in lithium-ion batteries at high rates.[7] The study presents a comprehensive analysis of the structural and morphological properties of various Li4Ti5O12, materials and their correlation with electrochemical performance. The results of the analysis revealed that there was a correlation between high capacity retention at 10 C and the specific surface area. In other words, the greater the specific surface area, the better the high-rate performance of Li4Ti5O12, materials. This study also discusses that other electrochemical and structural factors, including the crystal size, were not correlated with 10 C performance. The study also found that any increase in the specific surface area of Li4Ti5O12, beyond 15 m2 g−1 did not improve the high rate capacity retention or the specific discharge capacity at high current rates. This suggests that an optimal specific surface area of Li4Ti5O12 is essential for high-rate performance. Furthermore, the study showed that lithium titanium oxide powders synthesized via sol-gel retained similar or higher discharge specific capacities than materials synthesized via more complex routes.This work was supported by The National Centre for Research and Development through the research grant “Efficient and light photo-rechargeable electric energy storage systems based on solar cell—lithium-ion battery or solar cell-supercapacitor structures for special applications”, grant No. TECHMATSTRATEG1/347431/14/NCBR/2018. Ohzuku, T.; Ueda, A.; Yamamoto, N. Zero-Strain Insertion Material of Li[Li1/3Ti5/3]O4 for Rechargeable Lithium Cells. Electrochem. Soc. 1995, 142, 1431–1435.Panero, S.; Reale, P.; Ronci, F.; Scrosati, B.; Perfetti, P.; Rossi Albertini, V. Refined, in-Situ EDXD Structural Analysis of the Li[Li1/3Ti5/3]O4 Electrode under Lithium Insertion-Extraction. Chem. Chem. Phys. 2001, 3, 845–847.Young, D.; Ransil, A.; Amin, R.; Li, Z.; Chiang, Y.M. Electronic Conductivity in the Li4/3Ti5/3O4-Li7/3Ti5/3O4 System and Variation with State-of-Charge as a Li Battery Anode. Energy Mater. 2013, 3, 1125–1129.Prosini, P.P.; Mancini, R.; Petrucci, L.; Contini, V.; Villano, P. Li4Ti5O12 as Anode in All-Solid-State, Plastic, Lithium-Ion Batteries for Low-Power Applications. Solid State Ion. 2001, 144, 185–192.Sethuraman, V.A.; Hardwick, L.J.; Srinivasan, V.; Kostecki, R. Surface Structural Disordering in Graphite upon Lithium Intercalation/Deintercalation. Power Sources 2010, 195, 3655–3660.Yuan, T.; Tan, Z.; Ma, C.; Yang, J.; Ma, Z.F.; Zheng, S. Challenges of Spinel Li4Ti5O12 for Lithium-Ion Battery Industrial Applications. Energy Mater. 2017, 7.Llaín-Jiménez, H.A.; Buchberger, D.A.; Winkowska-Struzik, M.; Ratyński, M.; Krajewski, M.; Boczar, M.; Hamankiewicz, B.; Czerwiński, A. Correlation between Lithium Titanium Oxide Powder Morphology and High Rate Performance in Lithium-Ion Batteries. Batteries 2022, 8, 168. Figure 1

Identification of the Limiting Factors to Improve the Cycling Stability of Sulfide-Based ASSBs

All-Solid-State Batteries (ASSBs) have emerged as a highly promising post-lithium-ion battery technology, offering notable advancements in safety and energy density. However, an intrinsic disadvantage arises from the usually higher density of inorganic solid electrolyte materials compared to their liquid counterparts, constituting a drawback that hinders gains in overall energy density. To overcome this limitation, the imperative is to transition towards higher specific capacity materials, thereby unlocking the full potential for enhancing the energy density of ASSBs. On the cathode front, research predominantly centers around layered transition metal oxide materials like NMC, already widely employed in traditional lithium-ion batteries (LIBs). Simultaneously, on the anode side, there is a progressive shift from conventional graphite to silicon, which boasts an almost tenfold higher specific capacity, offering a compelling avenue to elevate the overall performance of ASSBs. Contemplating the potential upscaling of ASSBs, the most mature technology currently revolves around sulfide-based materials. Despite the considerable progress in research, only a limited number of studies have explored the cycling stability of ASSB full-cells at this stage.[1,2,3,4,5] This critical evaluation is essential, as it serves as the foundational evidence for the viability of a potentially commercial application.In this work, we studied the cycling stability of full-cell ASSBs, composed of an Li6PS5Cl solid electrolyte separator sheet, and NMC622-Li6PS5Cl composite cathode, and a microcrystalline-silicon-rich (>94 wt. %) anode. Emphasizing the foundational role of uniaxial pressure during both assembly and operation, we aimed to elucidate its crucial impact on cell performance. It became evident that, beyond just the magnitude, the in-plane distribution of pressure plays a pivotal role in achieving and sustaining effective contacts across multiple solid-solid interfaces. Significantly elevated pressures, reaching up to 500 MPa, proved necessary for the complete densification of the composite cathode and for establishing optimal contact within the 2D area between the anode and the separator. Furthermore, maintaining a homogeneous operational pressure of at least 20 MPa emerged as a key factor in ensuring a stable cycle-life at a C/3 current rate for over 400 cycles until 20% capacity loss, as exemplary showed in Figure 1. This promising cycle life was observed for cells with an areal capacity of 2.9 mAh/cm², highlighting the critical interplay between pressure and overall cycling performance in full-cell ASSBs.The second part of our investigation focused on determining the primary factors that contribute to the capacity fading observed in the here-examined ASSB full-cells. We endeavored to categorize these factors into two main groups, related to either increasing kinetic overpotentials or to active material losses. Within the first group, kinetic limitations could originate from either the anode or the cathode side, potentially due to ineffective/unstable solid electrolyte interphases at the anode (SEI) and/or at the cathode (CEI). These interphases are known to conduct ions less effectively than the Li6PS5Cl itself. Additionally, contact resistance arising from void formation and diffusion resistance due to a more tortuous lithium diffusion pathway in the active material, possibly caused by cracking, were identified as potential contributors to kinetic overpotential. In the material losses group, scenarios were explored where the active material could undergo chemical inactivity, such as the NMC crystalline transformation from a layered to a rock-salt structure at high potential. Mechanical inactivity might also occur when a portion of the active material becomes ionically and/or electrically disconnected from the rest of the cell stack. Finally, a critical focus was placed on lithium inventory loss, a phenomenon where lithium undergoes electrochemical consumption in parasitic reactions like the reduction of Li6PS5Cl to LiCl, Li3P, and Li2S during SEI growth.Upon thorough examination, it became evident that a homogeneously applied compressive force is able to render the kinetic overpotential negligible during cycling by maintaining the contact between the several components of the cells. Therefore, the lithium inventory loss emerged as the predominant factor contributing to the observed capacity fading in the studied ASSB full-cells.

Enhancing Efficiency, Stability, and Cycle Life of Lithium Metal Electrodeposition in Dry Solid-State Polymer Electrolytes.

Dry solid polymer electrolytes (SPEs), particularly those based on poly(ethylene oxide) (PEO), hold significant potential for advancing solid-state Li-metal battery (LMB) technology. Despite extensive research over the years, a comprehensive evaluation of Coulombic efficiency (CE), deposit stability, and cycle life for reversible Li metal electrodeposition in SPE-based cells is still lacking. In this study, we systematically assess the effect of cycling conditions on the CE of Li|SPE|Cu half cells and provide a thorough examination of different electrolyte chemistries, highlighting and explaining their performance across various parameters. While the efficiency of the PEO-based SPEs still falls short of the efficiency benchmark set by liquid and gel electrolytes, we demonstrated >95% CE with Lithium bis(fluorosulfonyl)imide (LiFSI)-based SPEs, surpassing previous reports for dry SPEs in a Li|SPE|Cu cells, this result marks a significant breakthrough. Furthermore, our findings highlight the critical impact of the Li-SPE interphase on these performance metrics. The LiFSI-based SPE forms a Li-rich, high-conductivity interphase, which not only enhances efficiency but also improves cycle life and Li deposit stability. These results underscore the importance of selecting the right polymer electrolyte chemistry and concentration to enhance SPE performance.

Functional separator inhibits dissolution of active materials to achieve stable cycling of alkaline batteries

Alkaline zinc-manganese batteries have attracted significant attention due to their low cost, high theoretical capacity, safety and stability. However, the notorious problem of manganese dissolution aggravates its irreversible capacity degradation, leading to an inferior cycle life. In this work, we functionalized a non-woven (NW) separator, exhibiting great ionic conductivity, mechanical strength, and high temperature resistance. Additionally, the abundant groups (-OH) on the functionalized separator are able to inhibit the migration of Mn(OH)63−. Following the Le Chatelier principle, it makes the dissolution-precipitation reaction of the active materials to proceed in the direction of precipitation, thereby significantly suppressing the dissolution problem of the active materials. The Zn//MnO2 full battery with the modified separator (Agar: GPTMs = 1) exhibits the discharge specific capacity of 120.8 mAh g−1 after 400 cycles at a current density of 0.2 A g−1, with a capacity retention rate of 83.1 %. This work provides a new idea to improve the cycle life and cycle stability of alkaline zinc-manganese batteries.

Engineering Electrolytes with Transition Metal Ions for the Rapid Sulfur Redox and In Situ Solidification of Polysulfides in Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries have been pursued due to their high theoretical energy density and superb cost-effectiveness. However, the dissolution-conversion mechanism of sulfur inevitably leads to shuttle effects and interface passivation issues, which impede Li-S battery practical application. Herein, the approach of adopting transition metal salts (CoI2) to engineering the electrolyte is proposed. Different from anchored transition metal catalysts in the cathode, soluble cobalt ions can chemically reduce and solidify polysulfides, alleviating the dependence of sulfur conversion on the conductive interface while suppressing the shuttle effect. Importantly, all elements in CoI2 are in the lowest valence state and solid complexes are formed after the redox reaction, which prevents the migration of high valent Co3+ to the anode, thus overcoming the poor compatibility between redox mediator and Li anode. Notably, I3- has the function of eliminating dead sulfur and dead lithium, which we apply to Li-S batteries. After activating I3- at a certain frequency, Li-S batteries indeed achieve a longer and more stable cycle life. By combining the regulatory behavior of anions and cations, the electrolyte is engineered for Li-S batteries with high capacity, long lifespan, and excellent rate performance.

Achieving the dendrite-free zinc anode by constructing a Sn-C interfacial layer with zincophilic and conductive network

Under the basic national policy of sustainable green development, high-performance and low-cost energy storage devices are urgently needed for intermittent generation of clean energy and storage of electrical energy. Zn metal with high capacity, abundant reserves and excellent plasticity, but the inevitable side reactions of the Zn metal anode itself have severely limited the development of aqueous Zn ion batteries (AZIBs) in the market. In this study, an artificial protective layer of polymer-derived carbon material combined with Sn is prepared to inhibit hydrogen precipitation and corrosion and prolong the lifetime of AZIBs. With these advantages, the Zn@Sn@N doped carbon (Zn@CNS) symmetric cell could achieve a stable cycle life of 1000 h at 2 mA cm−2 and low overpotential. The excellent stripping life of over 400 h is achieved in half-cells assembled with Cu foils. Furthermore, the α-MnO2//Zn@CNS full battery shows superior stability in rate capability and long-term capacity retention compared to the α-MnO2//Zn battery, indicating that the CNS coating provides excellent performance and practical value.

Robust polymer electrolytes with fast ion-transport nanochannels constructed by carbon dots for long lifespan Li metal batteries

As an anode material in energy storage systems, Li metal has exceptional merits, including high specific capacity, low density, and low redox potential. However, challenges such as lithium dendrites and unstable solid electrolyte interphase (SEI) hinder the practical application of lithium metal batteries (LMBs). Solid polymer electrolytes (SPEs), notably PVDF-HFP, are expected to overcome the above problems because of their mechanical merits and safe features, but their limited ion transportation behaviors result in insufficient ionic conductivity at room temperature. Herein, we invent an approach to prepare high performance electrolytes composed by porous PVDF-HFP and functionalized carbon dots (CDs). Such porous PVDF-HFP polymer membranes are created by a subtle phase inversion process, possessing a sponge-like structure, vertical lithium-ion transport channels and CDs decorated surfaces, thus able to uptake the liquid electrolyte (LE) to form gel polymer electrolytes (GPEs). The CDs fillers are produced in large scale with adjustable surface states, which can enhance Li salts disassociation to release free Li ions. As a result, the optimal conductivity of the as-prepared GPEs at room temperature is up to 8.7 mS cm−1 and the lithium transference number reaches 0.64. Our GPEs endow Li symmetric batteries with very stable SEI and long cycling life over 2200 h, and help realize high capacities and retention rates of the LMBs using LiFePO4(LFP) or LiCoO2(LCO) cathodes.

Facile Electrodeposition Method for Constructing Li2S as Artificial Solid Electrolyte Interphase for High-Performance Li Metal Anode.

Designing current collectors and constructing efficient artificial solid electrolyte interphase (SEI) layers are promising strategies for achieving dendrite-free Li deposition and practical applications in Li metal batteries (LMBs). Electrodeposition is advantageous for large-scale production and allows the direct formation of current collectors without binders, making them immediately usable as electrodes. In this study, an adherent Cu2S thin-layer on Cu foil is synthesized through anodic electrodeposition from a Na2S solution in a one-step process, followed by the generation of Li2S layers as artificial SEI layers via a conversion reaction (3DLi2S-Cu foil). The Li2S layers move from the 3D Cu surface to the deposited Li surface, facilitating uniform and dense Li deposition. The 3DLi2S-Cu foil structure demonstrates stable cycling performance over 350 cycles in an asymmetric cell, with a capacity of 1 mAh cm-2 at 1 mA cm-2. Moreover, symmetric cells with 5 mAh cm-2 of deposited Li exhibit a stable cycle life for over 1200 h. When paired with commercial LiFePO4 (LFP), the full cells show substantially enhanced cyclability, regardless of the amount of deposited Li. This study provides new insights into the construction of artificial SEIs for facilitating commercial applications.

Reviving Multivalent-Metal Anodes in Simple Salt Electrolytes via Component Modifier Design.

Using combinatory electrolyte blends represents an imperative avenue to achieve good magnesium (Mg)-metal anode compatibility and commercial feasibility in fields of promising rechargeable Mg batteries. However, fundamental challenges of how to manipulate component modifier reactivity on molecule level still remain to be solved. Here, molecular structure design concepts towards seeking bromophenyl complex-based component modifiers has been proposed according to implications of electron-donating and/or electron-withdrawing substituents on Br-C bond dissociation reactivity. Exceptional Mg electro-plating/stripping properties (a stable cycle life of 250 days in Mg//Cu asymmetric cells) have been firstly achieved in a simple salt electrolyte with 1-(3-bromophenyl)-N,N-dimethylmethanamine (BPDMA) as optimal component modifier. Comprehensive analyses disclose the unique electrochemically-active Br-containing ion-pairs formation, such as [(Mg2+)2(TFSI-)Br-]2+ and [(Mg2+)2(TFSI-)(Br-)(G2)2]2+, which results in the much thinner Br- containing and organic-inorganic mixed interphases on Mg-metal anodes. Furthermore, conventional MgSO4-based electrolytes and even calcium (Ca)-ion electrolytes can also be revived by similar strategy, demonstrating its generality and superiority.

Reviving Multivalent‐Metal Anodes in Simple Salt Electrolytes via Component Modifier Design

AbstractUsing combinatory electrolyte blends represents an imperative avenue to achieve good magnesium (Mg)‐metal anode compatibility and commercial feasibility in fields of promising rechargeable Mg batteries. However, fundamental challenges of how to manipulate component modifier reactivity on molecule level still remain to be solved. Here, molecular structure design concepts towards seeking bromophenyl complex‐based component modifiers has been proposed according to implications of electron‐donating and/or electron‐withdrawing substituents on Br−C bond dissociation reactivity. Exceptional Mg electro‐plating/stripping properties (a stable cycle life of 250 days in Mg//Cu asymmetric cells) have been firstly achieved in a simple salt electrolyte with 1‐(3‐bromophenyl)‐N,N‐dimethylmethanamine (BPDMA) as optimal component modifier. Comprehensive analyses disclose the unique electrochemically‐active Br‐containing ion‐pairs formation, such as [(Mg2+)2(TFSI−)Br−]2+ and [(Mg2+)2(TFSI−)(Br−)(G2)2]2+, which results in the much thinner Br− containing and organic–inorganic mixed interphases on Mg‐metal anodes. Furthermore, conventional MgSO4‐based electrolytes and even calcium (Ca)‐ion electrolytes can also be revived by similar strategy, demonstrating its generality and superiority.

Construction of iodine-rich solid electrolyte interphase to achieve highly stable aqueous zinc-ion batteries

Aqueous zinc ion batteries (AZIBs) are considered highly potential secondary energy storage equipment for their higher energy density, lower risk, and affordability. However, parasitic reactions within the anode affect the Zn2+ deposition behavior with uncontrollable dendrite formation significantly shortening the battery lifetime. For improvement of the Zn anode cycling stability, tetraethylammonium iodide (TEAI), a multifunctional additive was introduced into ZnSO4, which constructs an iodine-rich solid electrolyte interphase (SEI) on the zinc anode surface and significantly inhibits the parasitic reactions and nucleation of zinc dendrites. Furthermore, the TEAI also reshapes the solvation sheath of Zn2+, contributing to better transportation kinetics of zinc ions. Attributing to these functions, highly stable AZIBs are realized with the addition of TEAI, in which a stable cycling life of over 3500 h was achieved for symmetric Zn//Zn batteries under 1 mA cm-2. With higher current densities, the battery also exhibited excellent cycling stability over 3500 h. Full cells with the V2O5 cathode were fabricated to examine the commercial availability of TEAI additives, achieving a high reversible discharge capacity of 381 mAh g-1, and the capacity of 102 mAh g-1 was still maintained after 800 cycles at 1 A g-1.

Metal‐Organic Framework Hosted Silicon for Long‐Cycling, Low‐Cost, and Flexible Batteries

AbstractDeveloping biodegradable electrodes is a significant step toward environmental sustainability and cost reduction in battery technology. This paper presents a new approach that utilizes metal‐organic framework (MOF)‐encapsulated silicon nanoparticles (SiNPs) as the active anode material within a cellulose‐based electrode. The electrode is free‐standing, flexible, biodegradable, and significantly reduces the strain experienced by SiNPs during volume expansion, resulting in improved capacity and cycle life stability of SiNPs. The high porosity of the electrode creates efficient lithium (Li+) ion transport channels and enhances electrolyte absorption, thus promoting effective contact between the electrolyte and active material. The outcome is rapid electrode kinetics and a highly reversible discharge capacity of 1744.6 mAh g−1 at 0.5 A g−1 versus Li/Li+ over 1000 cycles. Further, full cell tests are conducted that demonstrate a stable cycle performance exceeding 3400 cycles, with an initial discharge capacity retention of 80.5% at 0.5 A g−1. By employing cellulose and avoiding toxic organic solvents and binders, the proposed approach is promising for a substantial reduction of the production costs of Li‐ion batteries. The scalability of the proposed method further enhances its practical viability, offering intriguing economic implications for the future of battery technology.

In Situ Alloying Enabled by Active Liquid Metal Filler for Self‐Healing Composite Polymer Electrolytes

AbstractSolid inorganics, known for kinetically inhibiting polymer crystallization and enhancing ionic conductivity, have attracted significant attention in solid polymer electrolytes. However, current composite polymer electrolytes (CPEs) are still facing challenges in Li metal batteries, falling short of inhibiting severe dendritic growth and resulting in very limited cycling life. This study introduces Ga62.5In21.5Sn16 (Galinstan) liquid metal (LM) as an active liquid alternative to conventional passive solid fillers, aiming at realizing self‐healing protection against dendrite problems. Compared to solid inorganics, for example silica, LM droplets could more significantly reduce polymer crystallinity and enhance Li‐ion conductivity due to their liquid nature, especially at temperatures below the polymer melting point. More importantly, LMs are unraveled as dynamic chemical traps, which are capable of blocking and consuming lithium dendrites upon contact via in situ alloying during battery operation and further inhibiting dendritic growth due to the lower deposition energy barrier of the formed Li‐LM alloy. As a proof of concept, by strategically designing an asymmetric CPE with the active LM filling, a solid‐state Li/LiFePO4 battery achieves promising full‐cell functionality with notable rate performance and stable cycle life. This active filler‐mediated self‐healing approach could bring new insights into the battery design in versatile solid‐state systems.