Sulfide solid-state electrolytes (SSEs) for all-solid-state lithium batteries (ASSLBs) have garnered significant attention due to their ultra-high ionic conductivity and favorable processing characteristics. However, their widespread adoption is severely hampered by poor compatibility with lithium metal and inadequate air stability. Herein, we develop a novel solid electrolyte, Ultra-efficient and stable Janus interface to construct high-performance sulfide-based ASSLBs (LPSC-NdO), which simultaneously achieves high ionic conductivity (8.75 mS cm-1) and outstanding electrochemical stability. This SSE demonstrates exceptional interfacial compatibility for a critical current density of 6.62mAcm-2 and stable lithium plating/stripping for over 2000 hours in symmetric cells. Full ASSLBs employing LiCoO2 (LCO) cathode exhibit remarkable cycling stability, with 95.4% capacity retention after 1000 cycles at 1C. Moreover, LPSC-NdO possesses excellent air stability, releasing only a minimal amount of H2S (0.67 cm3 g-1) upon exposure to moisture. This work presents a feasible co-doping strategy for sulfide SSEs, offering useful insights for developing SSEs that balance air stability and lithium metal interfacial compatibility toward practical-oriented development.

Halide-based solid-state electrolytes (SSEs), such as Li3InCl6 (LIC), are promising catholytes for all-solid-state batteries (ASSBs) because of their high ionic conductivity and high-voltage stability. However, the aging mechanism between halide SSEs and Ni-rich cathodes (LiNixCoyMn1 -x-yO2, NCM) remain poorly understood. Herein, we investigate the state-of-charge (SoC)-dependent aging behavior of LIC/NCM composite cathodes and reveal a non-monotonic relationship between SoC and capacity retention after aging. Severe capacity loss occurs under both low- and high-SoC conditions, whereas high capacity retention is achieved after aging at a mid-range SoC. Comprehensive structural and chemical analyses uncover a synergistic aging mechanism: reductive decomposition of LIC dominates aging at low SoCs, while structural degradation of NCM accounts for aging at high SoCs. Furthermore, an ultrathin coating layer introduced onto the NCM particle surface via atomic layer deposition effectively suppresses interfacial reactions and enhances electrochemical stability, particularly during low-SoC storage. This work provides mechanistic insights into SoC-dependent interfacial aging in halide-based ASSBs and proposes both SoC management and interface engineering strategy to extend their calendar life.

All-solid-state batteries (ASSBs) are promising candidates for next-generation energy storage devices due to their high energy density and enhanced safety. Binder plays an irreplaceable role in stabilizing the electrode structure, enhancing carrier transport and modulating solid electrolyte interfaces by connecting each component of the electrode. The development of functional binders is seen as a key strategy to achieve higher energy densities of ASSBs. This review systematically examines recent progress in binder development, focusing on their roles, impacts, and failure mechanisms in ASSBs. It begins by outlining the specific functionalities required of binders in ASSBs and provides a comprehensive summary of their applications across different components, including the anode, cathode, and solid electrolyte. Furthermore, the review highlights innovative binder design principles while also summarizing key testing methods and advanced characterization techniques for evaluating binder performance. This review proposes future directions for binder design based on current developments and emerging technologies, with the aim of creating optimal binder systems for high-energy-density applications.

Abstract Over the past three decades, lithium‐based batteries have greatly influenced our daily lives. However, their limited energy density poses challenges in meeting growing demand. To increase energy density, lithium metal anode is considered critical. This review systematically examines the history of lithium metal anode development, highlights notable advances in fundamental understandings, materials design, and characterization techniques. Forthcoming opportunities are discussed to promote the practical applications of lithium metal anodes.

An ultraconformal chemo-mechanical stable cathode interface is established via a transformative mechanical strategy in all-solid-state lithium batteries, resulting in exceptional electrochemical performance in a wide temperature range.

金属锂由于其超高理论比容量和极低电极电势,被视为下一代高比能电池理想的负极材料之一.然而,在实用化的条件下其巨大的体积膨胀及不均匀锂沉积等问题成为障碍.构建三维复合金属锂负极是调控金属锂沉积的有效方法.本文首先对实用化条件下[超薄金属锂(<50μm),较低的负极/正极面容量比(<3.0)和较低的电解液量下(<3.0 g/Ah)]金属锂的沉积脱出规律进行总结,指出复合锂负极的设计是解决金属锂负极问题的有效途径.其次,本文从骨架材料的角度出发,综述了当前实用化条件下应用纳米以及微米结构骨架的复合锂负极的研究进展.目前人们也将制备的复合锂负极逐步在实用化条件下进行评测,并应用在软包电池中取得了较好的效果.在此基础上,本文还总结了当前复合锂负极研究面临的问题,指出应该采用解构的方法分析骨架的单个参数对锂沉积脱出行为的影响,从而对骨架材料进行理性的设计.同时,我们展望了复合锂负极未来的研究方向,以望促进高比能金属锂电池的发展.

The irreversible phase transition of LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode materials easily occurs in high voltage (> 4.5 V) charging processes, which aggravates the corrosion of electrolyte on the materials and seriously affects the safety and cycling performance of lithium-ion batteries. In this paper, K and Cl ions were dual-doped into NCM523 by a high-temperature solid state method, and then Al2O3 was coated on the surface of the NCM523 by a hydrothermal method to obtain the modified cathode materials. The crystal structure, morphology and surface state of the modified materials were analyzed, and the electrochemical performance was tested under high cut-off voltage (4.6 V). The results show that when the content of K and Cl dual-doping and Al2O3 coating are 1 mol.% and 2 wt.%, respectively, the comprehensive properties of the materials are excellent. The first discharge capacity of 0.1 C is 210 mAh g−1, and the irreversible capacity loss is reduced. Compared with pristine materials, the specific discharge capacity at 5 C was increased by 26 mAh g−1, and the capacity retention rate was improved by 16% after 100 cycles at 1 C. The dual-doping of K and Cl ions can inhibit the mixing of cations, enhance the bond strength between transition metal cations and O2−, and improve the structural stability and the Li+ transport rate. The Al2O3 coating separates the cathode materials from the electrolyte and inhibits the corrosion of the electrolyte to the cathode materials. Therefore, the electrochemical properties of the modified cathode materials are significantly improved.

The layered oxide cathodes with low and moderate nickel contents used in Li-ion batteries with highvoltage and energy density are receiving considerable attention, as they possess better cycle performance and higher safety compared with high-nickel cathode. In the work, the crystal structure and electrochemical performance at 4.6 V high voltage vs Li (+)/Li are studied by controlling the lithium content in Li1+xNi0.45Co0.1Mn0.45O2 (0.05 <= x <= 0.4). As the lithium content in Li1+xNi0.45Co0.1Mn0.45O2 increases, the as-synthesized sample is mixed with hexagonal R-3m and monoclinic C/2 m crystals, accompanied with the decreasing of a/c axis ratio and cation mixing. Consequently, the reversible capacities of Li1.3Ni0.45Co0.1Mn0.45O2 reach 208 mAh/g at C/10 and 115 mAh/g at a high rate of 10C, respectively. The suitable Li content can lead to the low anion mixing crystal structure and best electrochemistrical performance. (C) 2020 Published by Elsevier B.V.

Electrochemical performance of Prussian blue analogues (PBAs) as positive electrode materials for non-aqueous Na-ion batteries is known to be highly dependent on their synthesis conditions according to the previous researches. Na-rich PBAs, NaxM[Fe(CN)(6)]center dot nH(2)O where M = Mn, Fe, Co, and Ni, are prepared via precipitation method under the same condition. The structure, chemical composition, morphology, valence of the transition metals, and electrochemical property of these samples are comparatively researched. The PBA with Mn shows large reversible capacity of 126 mAh g(-1) in 2.0-4.2 Vat a current density of 30 mA g(-1) and the highest working voltage owning to high redox potential of Mn2+/3+ in MnN6 and Fe2+/3+ in FeC6. While, the PBA with Ni exhibits the best cyclability and rate performance though only 66 mAh g(-1) is delivered. The significant differences in electrochemical behaviors of the PBAs originate from the various properties depending on different transition metals.

Energy-storage technology is moving beyond lithium batteries to sodium as a result of its high abundance and low cost. However, this sensible transition requires the discovery of high-rate and long-lifespan anode materials, which remains a significant challenge. Here, the facile synthesis of an amorphous Sn2P2O7/reduced graphene oxide nanocomposite and its sodium storage performance between 0.01 and 3.0 V are reported for the first time. This hybrid electrode delivers a high specific capacity of 480 mA h g(-1) at a current density of 50 mA g(-1) and superior rate performance of 250 and 165 mA h g(-1) at 2 and 10 A g(-1), respectively. Strikingly, this anode can sustain 15 000 cycles while retaining over 70% of the initial capacity. Quantitative kinetic analysis reveals that the sodium storage is governed by pseudocapacitance, particularly at high current rates. A full cell with sodium super ionic conductor (NASICON)-structured Na3V2(PO4)(2)F-3 and Na3V2(PO4)(3) as cathodes exhibits a high energy density of over 140 W h kg(-1) and a power density of nearly 9000 W kg(-1) as well as stability over 1000 cycles. This exceptional performance suggests that the present system is a promising power source for promoting the substantial use of low-cost energy storage systems.

With the rapid development of flexible electronics, low-cost, flexible, high-energy-density power sources are urgently needed. Theoretically, the emerging rechargeable potassium-ion batteries (KIBs) could be a promising candidate due to the abundance and low cost of potassium resources. However, owing to the absence of high-performance cathode materials and effective methods to fabricate robust and soft electrodes, producing flexible KIBs remains a daunting challenge. Herein, cyanotype is successfully employed as a photographic printing technique for the fabrication of a low-cost, scalable, and flexible cathode. The combined advantages of optimized crystallinity and morphology of the cathode materials as well as the ultralight and robust nature of the flexible electrode endow the KIB with superior performance including high energy density (up to 232 Wh kg(-1)) and excellent flexibility. This low-cost and scalable photographic printing technique as well as the promising electrochemical results will promote the development of flexible electronics.

Due to the extensive application of green energy technologies, the demand of large-scale energy storage systems is increasing. As far as now, the most successful and widely used battery system is Li-ion battery (LIB). When the energy storage system is enlarged, however, the cost performance becomes a more dominant factor, which is not apparently the advantage of LIB. Therefore, many novel battery systems with low cost materials have been developed recently, such as Na-ion batteries and aqueous batteries. However, the working voltage of these batteries is limited because of the 0.3-V higher potential of Na+/Na than that of Li+/Li or limited electrochemical window of H2O. Consequently, energy density of these battery systems is not satisfied. On the other hand, potassium is an earth abundant element with a lower standard electrode potential than that of lithium in PC solution [1]. Hence, the cost benefit and high working voltage are expected at the same time in K-ion batteries. We have studied the KIB materials since 2013 and recently reported graphite negative electrode delivering 250 mAh/g with excellent reversibility and rate-capability based upon stage-1 KC8 formation by electrochemical potassium intercalation [1]. Obviously, another key to obtain the successful K-ion batteries is development of the promising positive electrode materials. Considering the larger ionic size of K+ ­, the insertion materials should provide the large diffusion tunnels. As a suitable positive electrode, Prussian blue analogues with open framework structure exhibit excellent electrochemical performance in Na-, K-ion aqueous and non-aqueous batteries in previous reports [2,3]. Herein, we propose non-aqueous K-ion batteries by developing hexacyanoferrate(II) compounds, K1.75Mn[FeII(CN)6]0.93·0.16H2O and K1.64Fe[FeII(CN)6]0.89·0.15H2O (denoted as K-Mn[Fe(CN)6] and K-Fe[Fe(CN)6], respectively) as affordable positive electrode materials. Furthermore, we demonstrate 4-volt class K-ion full cells with K1.75Mn[FeII(CN)6]0.93·0.16H2O and graphite electrodes for the first time to prove their feasibility as a high energy density battery system. K-rich Prussian blues studied here were synthesized by precipitation method. Electrochemical measurements were carried out using 2032 coin cell with 0.7 M KPF6 in EC: DEC (1:1) solution as electrolyte and potassium metal as negative electrode. Prussian blue electrode consisted of 70 % active material, 20 % Ketjen black and 10 % PTFE binder. As shown in Figure 1a, K-Fe[Fe(CN)6] exhibits two voltage plateaux during charge at 3.5 and 4.1 V and corresponding discharge plateaux at 3.4 and 3.9 V, while K-Mn[Fe(CN)6] exhibits higher discharge plateaux at 4.0 and 3.9 V. Thanks to the higher working voltage and reversible capacity, K-Mn[Fe(CN)6] electrode shows higher energy density (vs. Na as negative electrode) than K-Fe[Fe(CN)6], which is 520 Wh kg-1. Such high energy density is comparable to that of commercial LiCoO2 in Li cell. As potassium metal is violently reactive with water than lithium and sodium metals, a metallic K battery is highly dangerous and unrealistic for practical use. We demonstrated K-ion full cells performance, i.e. K+-shuttlecock cell consisting of graphite/K-Mn[Fe(CN)6] electrodes on Al current collectors, as shown in Figure 1b. The full cell delivers a reversible capacity of 110 mAh (g of K-Mn[Fe(CN)6])-1 with a mean operating voltage of 3.5 V. The K-ion battery also demonstrates reversible charge-discharge profiles and acceptable capacity retention/efficiency over 60 cycles. In this presentation, we will present new potassium insertion materials, binders, and electrolytes for advanced battery demonstration, of which the charge/discharge voltage is compatible with the voltage of conventional Li-ion battery. References [1] S. Komaba, T. Hasegawa, M. Dahbi, and K. Kubota, Electrochem. Commun., 60, 172 (2015). [2] A. Eftekhari, J. of Power Sources, 126, 221 (2004). [3] C. Wessells, S. Peddada, R. Huggins, Y. Cui, Nano Lett., 11, 5421 (2011). Figure 1

Sodium-ion batteries operating at ambient temperature hold great promise for use in grid energy storage owing to their significant cost advantages. However, challenges remain in the development of suitable electrode materials to enable long lifespan and high rate capability. Here we report a sodium super-ionic conductor structured electrode, sodium vanadium titanium phosphate, which delivers a high specific capacity of 147 mA h g −1 at a rate of 0.1 C and excellent capacity retentions at high rates. A symmetric sodium-ion full cell demonstrates a superior rate capability with a specific capacity of about 49 mA h g −1 at 20 C rate and ultralong lifetime over 10,000 cycles. Furthermore, in situ synchrotron diffraction and X-ray absorption spectroscopy measurement are carried out to unravel the underlying sodium storage mechanism and charge compensation behaviour. Our results suggest the potential application of symmetric batteries for electrochemical energy storage given the superior rate capability and long cycle life.

Recently, research on novel and low cost batteries has been widely conducted to realize large-scale energy storage systems. However, few of the battery systems have delivered performance equal to that of Li-ion batteries. Herein, we propose non-aqueous K-ion batteries by developing hexacyanoferrate(II) compounds (so-called Prussian blue analogues), K1.75Mn[FeII(CN)6]0.93·0.16H2O and K1.64Fe[FeII(CN)6]0.89·0.15H2O, as affordable positive electrode materials. In particular, K1.75Mn[FeII(CN)6]0.93·0.16H2O prepared by a simple precipitation process delivers a high capacity of 141 mA h g−1 at 3.8 V as the average operating potential, resulting in a comparable energy density to that of LiCoO2, with excellent cyclability and rate performance in K half-cells. Operando X-ray diffraction measurements reveal that the excellent electrochemical performance of this material is attributed to its open and flexible framework, which can realize fully reversible K+ extraction/insertion and a structural change from monoclinic to tetragonal via cubic phases. For the first time, we demonstrate an inexpensive high-voltage K-ion full cell with a K1.75Mn[Fe(CN)6]0.93·0.16H2O/graphite configuration to prove its feasibility as a new promising battery system for an environmentally friendly future.

Mg-Li hybrid batteries have attracted wide interest in recent years because of their potential safety as well as their cost benefit and high volumetric capacity. However, slow kinetic properties strongly hinder their commercial application. In this study, we have prepared spinel LiCrTiO4 by a solid-state reaction and have conducted a comprehensive study aimed at improving the performance of Mg-Li hybrid batteries by optimizing the dual-salt electrolyte. LiCrTiO4 has been found to show reversible discharge/charge capacities of 178 and 169 mA h g-1 in electrolytes of 1 m LiCl and 0.3 m APC (all-phenyl-complex), respectively. When the concentration of APC was increased to 0.4 m, LiCrTiO4 showed a high capacity retention of 95 % after 30 cycles. In addition, no phase transition could be observed for an LiCrTiO4 electrode in a dual-salt system, suggesting high electrochemical reversibility. Ex situ EDX and SEM studies have indicated that only Li+ ions are inserted into the cathode side, while Mg2+ ions are reversibly deposited on the surface of Mg metal without dendrite-like growth, indicative of good safety of the Mg-Li hybrid batteries.

Charging and discharging lithium ion batteries (LIBs) in a matter of seconds to tens of seconds rather than hours can potentially lead to technological breakthroughs and bring about lifestyle changes. This work aims to enable ultrafast Li-ions charge/discharge ability for LIBs by significantly accelerating the diffusion kinetics of Li+ ions and enhancing the electric conductivity in LiFePO4 cathode material. An innovative method was developed to synthesize LiFePO4/C nanocomposite with secondary particles structure containing uniform (20–50 nm) and highly crystalline LiFePO4 single nanoparticles which are free from any anti-site defects (e.g. Fe·Li) and uniformly coated by a highly graphitized carbon-shell network with good electronic conduction. The LiFePO4/C material was formed from a FePO4·xH2O/poly(furfuryl alcohol) nanocomposite, which was prepared through a self-regulated in situ polymerization restriction method, followed by a rapid wet-chemistry lithiation (H+/Li+ ion exchange) and subsequent calcination. Benefiting from the ultra-small size of the LiFePO4 nanoparticles, absence of Fe·Li defects, and a continuous 3D carbon network, the LiFePO4/C nanocomposite demonstrated ultrafast lithium-storage rates when used as a cathode material in lithium half-cells, which required only 21.6 s to reach a complete discharge at a rate of 150 C while still maintaining a high specific capacity of 95.4 mAh g−1.

In the past few years, Na–ion batteries have been considered as promising candidates for large-scale energy storage system instead of Li–ion batteries because of the natural abundant resources of sodium. Owing to the excellent cyclability and high rate performance, sodium iron hexacyanoferrate (NaFeHCF) with the general chemical formula Na x Fe[Fe(CN) 6 ] y · n H 2 O has been researched widely as positive electrode material for Na–ion batteries. However, off–stoichiometry of NaFeHCF, defects of [Fe(CN) 6 ] and Na, would deteriorate its reversible capacity. Therefore, much effort has been devoted to prepare stoichiometric Na 2 Fe[Fe(CN) 6 ] without crystal defects. For example, Guo and his co–workers have synthesized NaFeHCF with few defects of [Fe(CN) 6 ] and Na by a precipitation method with HCl solution [1]. During the precipitation synthesis, however, hazardous HCN and NaCN are inevitably produced on the decomposition reaction of Na 4 Fe(CN) 6 as a starting material in HCl solution. For safety and environmental concerns, other synthesis method should be used to prepare low–defects NaFeHCF. To avoid the HCN or NaCN generation and the defects of final product, control of nuclei formation and crystal growth process of synthesis without HCl is required in general. Because chelate has the ability to suppress the both process, trisodium citrate (Na 3 C 6 H 5 O 7 ) has been used as chelator for the preparation of Prussian blue analogues such as NaCoHCF and NaNiHCF [2,3]. Recently, Liu et al. reported the precipitation chelate synthesis of NaFeHCF with trisodium citrate [4]. However, the NaFeHCF shows insufficient electrochemical property because it would have lower crystallinity than that of NaFeHCF synthesized with HCl. In this study, we optimize the synthesis condition with using trisodium citrate to obtain low–defects and highly redox-acitive NaFeHCF and systematically investigate the synthesis process, crystal structure, particle morphology and electrochemical properties of NaFeHCF. Na 4 Fe(CN) 6 and FeCl 2 were separately dissolved in 0.2 M trisodium citrate or NaCl solutions. These two solutions were slowly mixed together with stirring under N 2 atmosphere. Then, the precipitate was centrifuged and washed with deionized water and ethanol. The final products synthesized with citrate or NaCl (hereafter denoted as Cit–NaFeHCF or NaCl–NaFeHCF, respectively) were obtained after drying in vacuum oven for 24 h. Electrochemical measurements were carried out using 2032 coin cells with NaPF 6 dissolved in EC:DEC (1:1) solution as electrolyte and sodium metal as a negative electrode. Positive electrodes were prepared by mixing 70 wt.% active material, 20 wt.% Ketjen black carbon and 10 wt.% PVdF binder. The charge and discharge measurements were carried out at room temperature at a current density of 60 mA g –1 in the voltage range of 2.0 – 4.2 V vs. Na/Na + . Figure 1 shows the XRD patterns of Cit–NaFeHCF and NaCl–NaFeHCF. Diffraction lines of Cit–NaFeHCF can be indexed with a space group of P 2 1 / n and no diffraction lines from impurity phases were observed, which is similar to those of NaFeHCF synthesized with HCl solution in the literature [1]. On the other hand, the diffraction peaks at 24 and 38° for NaCl–NaFeHCF were a single line without splitting, which indicates that the crystal structure of NaCl–NaFeHCF is cubic and the diffraction lines can be indexed with a space group of Fm –3 m . This structural difference between two samples implies that NaFeHCF having fewer defects of [Fe(CN) 6 ] and Na was successfully prepared with trisodium citrate compared to those of the material synthesized with NaCl. Figure 2(a) shows the initial charge/discharge curves of Cit–NaFeHCF and NaCl–NaFeHCF in Na cells. Initial charge capacity of NaCl–NaFeHCF was lower than that of Cit–NaFeHCF because of the large number of Na defects. In contrast, initial charge capacity of Cit–NaFeHCF was slightly higher than initial discharge capacity, which indicates few Na defects in Cit–NaFeHCF. Additionally, the discharge capacity of Cit–NaFeHCF was higher than that of NaCl–NaFeHCF and reversible capacity of 156 mAh g –1 is obtained as high as that for the material synthesized with HCl [1]. Furthermore, Cit–NaFeHCF exhibits better capacity retention over 50 cycles than that of NaCl–NaFeHCF. The structural and morphological differences based on the synthesis process will be discussed in detail. References: [1] Y. You and Y. Guo et al ., Nano Res. , 8 (1), 117 (2015) [2] X. Wu and H. Yang et al ., ChemNanoMat., 1 (3), 188 (2015) [3] Y. Chiang and Y. Yamauchi et al ., Eur. J. Inorg. Chem ., 18, 3141 (2013) [4] Y. Liu and Y. Huang et al ., Nano Energy , 12 , 386 (2015) Figure 1

NASICON-type structured NaTi2(PO4)3 (NTP) has attracted wide attention as a promising anode material for sodium-ion batteries (SIBs), whereas it still suffer from poor rate capability and cycle stability due to the low electronic conductivity. Herein, the architecture, NTP nanoparticles embedded in the mesoporous carbon matrix, is designed and realized by a facile sol-gel method. Different than the commonly employed potentials of 1.5-3.0 V, the Na(+) storage performance is examined at low operation voltages between 0.01 and 3.0 V. The electrode demonstrates an improved capacity of 208 mAh g(-1), one of the highest capacities in the state-of-the-art titanium-based anode materials. Besides the high working plateau at 2.1 V, another one is observed at approximately 0.4 V for the first time due to further reduction of Ti(3+) to Ti(2+). Remarkably, the anode exhibits superior rate capability, whose capacity and corresponding capacity retention reach 56 mAh g(-1) and 68%, respectively, over 10000 cycles under the high current density of 20 C rate (4 A g(-1)). Worthy of note is that the electrode shows negligible capacity loss as the current densities increase from 50 to 100 C, which enables NTP@C nanocomposite as the prospective anode of SIBs with ultrahigh power density.