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KAP1 with porous surface structure and reasonable hydrogen bonding are used as fillers in PEO-based CPEs that could solve the compatibility of fillers in polymer-based electrolytes and provide a valuable reference for the design of high-performance ASSLMBs. [Display omitted] Achieving practical applications of PEO-based composite solid electrolyte (CPE) batteries requires the precise design of filler structures at the molecular level to form stable composite interfacial phases, which in turn improve the conductivity of Li+ and inhibit the nucleation growth of lithium dendrites. Some functional fillers suffer from severe agglomeration due to poor compatibility with the polymer base or grain boundary migration, resulting in limited improvement in cell performance. In this paper, ILs@KAP1 is reported as a filler to enhance the performance of PEO-based batteries. Thereinto, the hypercrosslinked phosphorus ligand polymer-containing KAP1, designed at the molecular level, has an abundant porous structure, hydrogen bonding network, and a rigid skeleton structure of benzene rings. These can be used both to improve the flammability with PEO-based and to reduce the crystallinity of the polymer electrolyte. Ionic liquids (ILs) are encapsulated in the nanochannels of KAP1, and thus a 3D Li+ conducting framework could be formed. In this case, it could not only facilitate the wettability of the contact interface with the electrode, significantly promoting its compatibility and providing a fast Li+ transport path, but also facilitate the formation of LiF, Li 3 N and Li 2 O rich SEI components, further fostering the uniform deposition/exfoliation of lithium. The LFP||CPE||Li battery assembled with ILs@KAP1-PEO-CPE has a high initial discharge specific capacity about 156 mAh/g at 1C and a remaining capacity about 121.8 mAh/g after 300 cycles (capacity retention of 78.07%). [ABSTRACT FROM AUTHOR]

Rechargeable Zn‐ion batteries (ZIBs), prospective candidates for broad‐scale energy storage, still encounter many challenges such as hydrogen evolution corrosion, Zn dendrite growth, and capacity fading. Therefore, one specific strategy for tuning the internal structure of solid polymer electrolytes (SPEs) via organic additives is proposed to address these urgent bottlenecks simultaneously. With trimethyl phosphate (TMP) addition, the coordination environment of Zn2+ in SPEs is altered and exists as Zn2+(TMP)x(OTf−)y coordinated molecules. Meanwhile, the strong interaction between TMP and Zn enables the preferential growth of Zn(002) planes during electrodeposition, which is proved based on first‐principles calculations, finite element simulations, and multiple in situ characterizations. Such excellent interfacial engineering in situ forms the solid electrolyte interface rich in Zn3(PO4)2 fast ion conductor and guarantees one ultra‐long cycle life for more than 6000 h in a Zn|Zn symmetric cell at 0.1 mA cm−2. Moreover, the universality of TMP‐modified SPEs shows 1000 times stable cycling of VO2(B)|Zn full cells at 1 A g−1 under 0 °C with 95.24% capacity retention, which satisfies potential applications of wide‐ranging energy storage based on solid‐state ZIBs. [ABSTRACT FROM AUTHOR]

The undesirable side reactions and uncontrolled deposition leads to the electrochemical failure of Zn metal anodes. Herein, driven by theory calculations, a surface texture engineering and passivation layer protection dual‐interface strategy is developed. Benefiting from the complementary interface effect, such a dual‐interface can realize the integrated regulation of interfacial transport and deposition. That is, inhibiting water‐induced side reactions, accelerating the de‐solvation of hydrated zinc ions, homogenizing the ion flux, and guiding the Zn(002)‐preferred orientation deposition. As a result, such a dual‐interface modulated Zn electrode enables a significantly extended stability and a smaller nucleation barrier and polarization effect. Unexpectedly, it can steadily operate for 6600 h at 0.5 mA cm−2 and 0.5 mA h cm−2, corresponding to a lifespan >9 months. Highly reversible Zn plating and stripping can be still retained when the current density is improved up to 1, 5, 10, and even 20 mA cm−2. Beyond that, when it is applied to Zn metal batteries, enhanced rate capability, and cyclic stability can be realized in both aqueous Zn/MnO2 batteries and solid‐state Zn/VO2 batteries. This design concept of complementary interface effect is expected to provide a new insight into high reversibility Zn metal anodes. [ABSTRACT FROM AUTHOR]

Sluggish transport kinetics and unstable electrode–electrolyte interface are the main obstacles that greatly impair the electrochemical performance of solid‐state Zn metal batteries. Herein, the concept of multifunctional MXene bonded transport network‐embedded poly(vinylidene fluoride co‐hexafluoropropylene)/Zn(OTf)2 solid polymer electrolyte (PH/MXene SPE) is proposed as "all‐in‐one" strategy for designing robust SPE. In order to uncover the mechanism of such rational designed SPE on regulating the ion transport, as well as the interphase chemistry and Zn deposition, comprehensive research including density functional theory calculation, simulation, and multiple characterization techniques are carried out. As the results indicate, the formation of hydrogen bond network between the MXene nanofiller and PH polymer benefits fast and homogeneous ion transport. Then, the in situ formation of stable organic/inorganic hybrid interphase is capable to ensure the efficient interfacial transport kinetics and uniform Zn deposition. When such PH/MXene SPE is applied, ultrastable Zn plating/stripping behavior with small polarization voltage can be realized. In addi, solid‐state Zn/VO2 batteries with significantly improved rate performance and cyclic stability also can be demonstrated. The unique strategy proposed in this study offer a new insight into SPE design and the development of high‐performance solid‐state Zn metal batteries. [ABSTRACT FROM AUTHOR]

Lithium metal batteries (LMBs) have attracted extensive attention for their ultrahigh energy density. However, the uncontrollable growth of Li-dendrites results in poor cyclability and potential safety risks, thus preventing their practical application. Herein, a flexible and cost-effective aqueous polyethylene oxide (PEO)-based solid-state electrolyte is prepared, which enables uniform and dendrite-free Li deposition by introducing Cs+ with an electrostatic shielding mechanism at high current densities. The self-assembly of PEO and bacterial cellulose by hydrogen bonding reduces the crystallinity of PEO and increases uniformly the distribution of lithium ions. With excellent flexibility and thermal stability, such a 3D polymer solid-state electrolyte exhibits an enhanced electrochemical stability window of 5.8 V versus Li/Li+ potential and a high ionic conductivity of 1.28 × 10−4 S cm−1 at 60 °C. The Li‖BC-PEO-Cs+‖Li symmetric cells operate stably for more than 1000 h. Furthermore, Li‖BC-PEO-Cs+‖LiFePO4 (LFP) cells show remarkable enhancement in capacity (163.4 mA h g−1 at 0.1 C), cycling stability (with a capacity retention of 96% after 500 cycles at 1 C) and high functionality and safety (withstanding folding and cutting) in practical applications. [ABSTRACT FROM AUTHOR]

All‐solid‐state (ASS) lithium metal batteries (LMBs) are considered the most promising next‐generation batteries due to their superior safety and high projected energy density. To access the practically desired high energy density of ASS LMBs, an ultrathin solid‐state electrolyte (SSE) film with fast ion‐transport capability presents as an irreplaceable component to reduce the proportion of inactive materials in ASS batteries. In this contribution, an ultrathin (60 µm), flexible, and free‐standing argyrodite (Li6PS5Cl) SSE film is designed through a self‐limited strategy. A chemically compatible cellulose membrane is employed as the self‐limiting skeleton that not only defined the thinness of the sulfide SSE film but also strengthened its mechanical properties. The ionic conductivity of the SSE film reaches up to 6.3 × 10−3 S cm−1 at room temperature, enabling rapid lithium‐ion transportation. The self‐limited SSE thin films are evaluated in various ASS LMBs with different types of cathode (sulfur and lithium titanate) and anode materials (lithium and lithium‐indium alloy) at both mold‐cell and pouch‐cell levels, demonstrating a stable performance and high‐rate capability. This study provides a general strategy for the rational design of an SSE thin film towards high‐energy‐density ASS batteries. [ABSTRACT FROM AUTHOR]

The coordination environment of Li+ is adjusted by introducing FEC and the solvation structure of Li+ in the flame-retardant electrolyte is reshaped simultaneously. Furthermore, the higher LUMO energy level of FEC facilitates the formation of firm and dense SEI on the surface of the Gr electrode. The in-situ induced stable interface of this novel solvated structure not only suppresses the co-intercalation effect of TMPa solvent, but also enhances the even Li+ transport, contributing to the stable cycling of Li|Gr cells. [Display omitted] • A flame-retardant electrolyte with FEC involved in Li+ solvated structure is proposed. • In-situ induced LiF-rich SEI promotes structural integrity of graphite electrodes. • The modified Li|Gr cell delivers an excellent cycling performance for 300 cycles with 97.48% capacity retention. Conventional electrolytes with flammability and volatility may incur severe safety issues, which are impeding the application of lithium batteries on a large scale. Flame-retardant solvents are introduced into the electrolytes to enhance the security performance, while the battery electrochemical performance is compromised due to incompatibility between these solvents and graphite (Gr) anode. In this work, a flame-retardant electrolyte prepared by trimethyl phosphate (TMPa), lithium difluoro(oxalato)borate (LiDFOB) and fluoroethylene carbonate (FEC) could be expected to solve the dilemma via regulating the solvation structure of Li+ to suppress the co-intercalation effect of TMPa with Li+ and alleviate the compatibility issues of interface caused by the continuous reduction of LiDFOB. The formation mechanism of the solid electrolyte interface (SEI) at the graphite electrode was analyzed to explore the intrinsic reaction of the electrolyte at the electrode interface. The 300-cycle capacity retention of Li|Gr cell at 0.5C reaches 97.48 %, and the deposition and stripping performance of the Li|Li symmetric cell is also significantly improved. Such Li+ solvation structure modification provides a new idea for fire-extinguishing electrolyte design and helps to promote the industrialization of safe and eco-friendly electrolytes. [ABSTRACT FROM AUTHOR]

• PEO-based polymer electrolyte with KPF 6 additive was developed for improving the performance. • KPF 6 can reduce the crystallinity of PEO, and promote dissociations of LiTFSI. • KPF 6 can increase the ionic conductivity of PEO-based polymer electrolyte. • KPF 6 salt can regulate the formations of Li 2 S/LiF-rich SEI layer. • Li 2 S/LiF-rich SEI layer and K + electrostatic shielding led to a uniform Li deposition. High energy density all-solid-state lithium metal batteries (ASSLMBs) with flexible, low-cost solid polymer electrolytes (SPEs) have received extensive research attention, but the low ionic conductivity of SPEs and the rapid growth of lithium dendrite seriously limit their performance. Here, polyethylene oxide (PEO) based solid polymer electrolytes (SPEs) containing potassium hexafluorophosphate (KPF 6) salt additive are developed for lithium dendrite-free ASSLMBs. The results show that with the additive of KPF 6 , the dissociation of lithium salt is promoted, providing more free Li+ ions in SPEs and enhancing the ionic conductivity. KPF 6 additive also makes SPE more flexible and promotes the formation of Li 2 S and LiF-rich solid electrolyte interphase (SEI). Besides, the presence of K + is also expected to work as a shield to inhibit the lithium dendrite growth. With the synergistic effect of above advantages, lithium dendrite growth and interfacial side-reactions in ASSLMBs are prevented. Li/Li symmetric cell with SPE can achieve a stable cycling performance over 1500 h with low polarization potential. The all-solid-state LiFePO 4 /Li cell releases an initial capacity of 142.1 mAh g−1 with a capacity retention of 91.3% after 200 cycles at 0.5 C and 60 °C. This study provides a facile scheme for designing high performance ASSLMBs. [Display omitted] Solid-state lithium metal batteries with polyethylene oxide (PEO) based solid polymer electrolytes (SPEs) suffer from lithium dendrite problems. To address this challenge, KPF 6 is used as an additive to improve ionic conductivities and mechanical properties of SPEs. Moreover, KPF 6 is favorable to the formation of LiF-rich solid electrolyte interphase. K + also works to suppress the lithium dendrite through shielding effects. [ABSTRACT FROM AUTHOR]