Search

Rechargeable multivalent‐ion batteries are attractive alternatives to Li‐ion batteries to mitigate their issues with metal resources and metal anodes. However, many challenges remain before they can be practically used due to the low solid‐state mobility of multivalent ions. In this study, a promising material identified by high‐throughput computational screening is investigated, ε‐VOPO4, as a Mg cathode. The experimental and computational evaluation of ε‐VOPO4 suggests that it may provide an energy density of >200 Wh kg−1 based on the average voltage of a complete cycle, significantly more than that of well‐known Chevrel compounds. Furthermore, this study finds that Mg‐ion diffusion can be enhanced by co‐intercalation of Li or Na, pointing at interesting correlation dynamics of slow and fast ions. [ABSTRACT FROM AUTHOR]

MoS2 nanosheets consist of multiple S-Mo-S trilayers with large interlayer spacing, which could allow facile Li-ion insertion/extraction. However, MoS2 nanosheets are easily curled and randomly stacked due to high surface energy of 2D nanosheets, which hinders fast ion transportation. In addition, intrinsic electronic conductivity of MoS2 is limited. Therefore, enhancements of both ionic and electronic conductivity of MoS2 are greatly demanded for its application in Li-ion batteries. Here, we report a cost-effective and facile hydrothermal synthesis of 3D nanoflower-like MoS2/C anode materials, which avoids random stacking of nanosheets and improves the electronic conductivity of MoS2. The nanoflower-like MoS2/C exhibits large reversible specific capacity (724 mAh g−1) and high initial coulombic efficiency (79.82%). Moreover, excellent capacity retention (97.98%) after 500-cycle charge/discharge has been achieved at 1 A g−1. [ABSTRACT FROM AUTHOR]

Recently, chiral and nonplanar cutouts of graphene have been the favorites due to their unique optical, electronic, and redox properties and high solubility compared with their planar counterparts. Despite the remarkable progress in helicenes, π‐extended heterohelicenes have not been widely explored. As an anode in a lithium‐ion battery, the racemic mixture of π‐extended double heterohelical nanographene containing thienothiophene core exhibited a high lithium storage capability, attaining a specific capacity of 424 mAh g−1 at 0.1 A g−1 with excellent rate capability and superior long‐term cycling performance over 6000 cycles with negligible fade. As a first report, the π‐extended helicene isomer (PP and MM), with the more interlayer distance that helps faster diffusion of ions, has exhibited a high capacity of 300 mAh g−1 at 2 A g−1 with long‐term cycling performance over 1500 cycles compared to the less performing MP and PM isomer and racemic mixture (150 mAh g−1 at 2 A g−1). As supported by single‐crystal X‐ray analysis, a unique molecular design of nanographenes with a fixed (helical) molecular geometry, avoiding restacking of the layers, renders better performance as an anode in lithium‐ion batteries. Interestingly, the recycled nanographene anode material displayed comparable performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Evolution fate of battery chemistry proposed for green discharging of spent LIBs; • Exploring relationship between the migration of metal ions and fast discharging; • Revealing galvanic corrosion mechanism on battery surface during discharging; • Chemical evolution outside battery is clarified for second pollution controlling; • Establishment of technological and theoretical basis for sustainable discharging. Residual electricity in spent lithium-ion batteries (LIBs) may cause safety issues during their dismantling and shredding in pretreatment processes. However, the migration and transformation of pollutants generated from spent LIBs during discharging were rarely reported, which is critical for prevention of pollution risk and facilitation of discharging efficiency. Herein, this work is focused on the evolution fate of battery chemistry during discharging processing. Here, migration of metal ions inside battery, galvanic corrosion on surface of battery and chemical evolution outside battery were investigated to attain the comprehensive understanding of discharging process. Firstly, efficient and complete discharging can be achieved using 5 wt% CuSO 4 as discharging medium, which mainly drive the migration of Li, instead of transition metals, from anode to cathode, resulting in enrichment of Li in cathode material. Besides, different degrees of galvanic corrosion phenomena on surface of spent LIBs can be discovered in different electrolyte solutions, involving with the corrosion of Al or Fe shells and resulting in the leakage of organic electrolytes inside battery into electrolyte solution. The detailed characterization results of the composition of solute indicate that hydroxide precipitates liberated from corroded shell and organic pollutants are their main existence states. [ABSTRACT FROM AUTHOR]

[Display omitted] Aqueous Zn-ion battery is expected to become a substitute for Li-ion battery due to its inherent safety, low cost, and environmental friendliness. Dendrite growth and side reaction problems during electroplating lead to its low Coulombic efficiency and unsatisfactory life, which greatly limits its practical application. Here, we propose a dual-salts hybrid electrolyte, which alleviates the above issues by mixing Zn(OTf) 2 to ZnSO 4 solution. Extensive tests and MD simulations have shown that the dual-salts hybrid electrolyte can regulate the solvation structure of Zn2+, facilitating uniform Zn deposition, and inhibiting side reactions and dendrite growth. Hence, the dual-salts hybrid electrolyte exhibits good reversibility in Zn//Zn batteries, which can provide a lifetime of more than 880 h at 1 mA cm−2 and 1 mAh cm−2. Moreover, the average Coulombic efficiency of Zn//Cu cells in hybrid system can reach 98.2% after 520 h, much better than that of 90.7% in pure ZnSO 4 electrolyte and 92.0% in pure Zn(OTf) 2 electrolyte. Benefiting from the fast ion exchange rate and high ion conductivity, Zn-ion hybrid capacitor in hybrid electrolyte also displays excellent stability and capacitive performance. This effective strategy for dual-salts hybrid electrolytes provides a promising direction for designing aqueous electrolytes for Zn-ion batteries. [ABSTRACT FROM AUTHOR]

PAN/PVDF nanofiber membranes with core–shell structures were fabricated by electrospinning to improve mechanical and electrochemical properties. [Display omitted] • With the excellent mechanical properties of PAN, the mechanical strength of PAN/PVDF nanofiber separator is increased by 6 times compared with pure PVDF separator; • The PAN/PVDF nanofiber separator takes into account the high electrolyte absorption capacity of PAN and the characteristics of PVDF to promote lithium ion transport, which significantly improves the ionic conductivity, reduces the activation energy during the lithium ion transport process, and improves the battery in high-power charge and discharge performance; • The PAN/PVDF nanofiber separator promotes the uniform transport of lithium ions, thereby inhibiting the formation of lithium dendrites; The ion transport channel constructed by the separator is crucial for the practical performance of Li-ion batteries, including cycling stability and high rate capability under high current. Traditional polyolefin separator is the storage of electrolyte, which guarantees the internal ion transport process. However, its weak interaction with electrolyte and low cationic transport capacity limit the application of lithium ion battery in large current. In this study, a kind of core–shell structured polyacrylonitrile (PAN)/polyvinylidene fluoride (PVDF) nanofiber separator composed of PAN core and PVDF shell was prepared by coaxial electrospinning technique. As a result, the mechanical strength of PAN/PVDF nanofiber separator is increased from 0.6 MPa of PVDF to 3.6 MPa for PAN core. Furthermore, PAN/PVDF nanofiber separator exhibits an improved lithium-ion transference number (0.66), which is resulted from F functional groups of PVDF shell. It is believed that the interactions between the lithium ion and F functional group could construct a fast ion transport channel. The LiCoO 2 /Li half-cells assembled with PAN/PVDF exhibited higher discharge capacity (5C) than those cells using pristine PVDF, PAN separators and polyethylene (PE) separator. It is worth mentioning that the cells with PAN/PVDF separator also have excellent cycle stability. This study provides a new idea about separator-design strategy for high-performance lithium-based battery. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries are gaining more attention due to the rapid growth of electrical vehicles (EVs). Additionally, the industry is putting a lot of effort into reusing EV batteries in energy storage systems (ESS). The optimal performance of the repurposed battery system is highly dependent on the individual batteries used in it. These batteries need to be similar in terms of battery capacity, state of health (SOH), and remaining useful life (RUL). Therefore, battery grading techniques are expected to play a vital role in this newly emerging industry. There are various methods suggested to evaluate the aging of a battery in terms of capacity, SOH, and RUL. The use of ohmic resistance is one approach, as it varies with the aging of the battery. In order to measure the ohmic resistance, electrochemical impedance spectroscopy (EIS) is used, followed by the curve fitting procedures. In this research a novel method is suggested to measure the ohmic resistance without performing the broadband conventional EIS test and the curve fitting. Since the battery is perturbed for a specified frequency band (1 kHz to 100 Hz) using the linearly distributed phased multi-sine signal, only 1 sec perturbation is required, and the ohmic resistance can be directly calculated by using two impedance values. Thus, the measurement speed is several times faster than that of the conventional EIS methods. Hence, it is a suitable and convenient technique for the mass testing of the batteries. The accuracy and validity of the proposed technique are verified by testing three types of batteries. The percentage difference in the measured ohmic resistance value between the conventional and the proposed technique is less than 0.15% for all the batteries tested. [ABSTRACT FROM AUTHOR]

Appropriate materials collaborated with reasonable structure can significantly increase the separator performance for lithium-ion batteries. In this work, taking the advantages of microfibrous and nanofibrous membranes and compensating for their defects, we developed a composited separator (GOPPH) with excellent overall performance by first wetting-modifying the polyethylene terephthalate microfibers and then laminating a polyvinylidene fluoride-hexafluoropropylene nanofiber layer. Such a combination not only offers the GOPPH separator, from the perspective of structure, with high porosity and hierarchical structure in terms of fiber diameter and pore size, but also provides satisfactory features including wettability, mechanical strength and thermal shutdown function that benefit from the selected materials. Meanwhile, as determined by experimental and theoretical approaches, the obtained GOPPH separator exhibits considerably enhanced lithium ion transport ability with a high lithium ion transference number and transport rate, which thereby endowing the cell with superior cycling stability with a capacity retention of 93% after 200 cycles at 1 C. Therefore, considering battery safety and performance, the GOPPH fibrous membrane could be a promising separator candidate for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Semiconductor-based composites are potential anodes for Li-ion batteries, owing to their high theoretical capacity and low cost. However, low stability induced by large volumetric change in cycling restricts the applications of such composites. Here, a hierarchical SnO2@Ni6MnO8 composite comprising Ni6MnO8 nanoflakes growing on the surface of a three-dimensional (3D) SnO2 is developed by a hydrothermal synthesis method, achieving good electrochemical performance as a Li-ion battery anode. The composite provides spaces to buffer volume expansion, its hierarchical profile benefits the fast transport of Li+ ions and electrons, and the Ni6MnO8 coating on SnO2 improves conductivity. Compared to SnO2, the Ni6MnO8 coating significantly enhances the discharge capacity and stability. The SnO2@Ni6MnO8 anode displays 1030 mAh g−1 at 0.1 A g−1 and exhibits 800 mAh g−1 under 0.5 A g−1, along with high Coulombic efficiency of 95%. Furthermore, stable rate performance can be achieved, indicating promising applications. [ABSTRACT FROM AUTHOR]

Li-rich layered oxides with high energy densities have become one kind of promising cathode for advanced lithium-ion batteries, however some issues are severely hindering their practical applications. To address these challenges, fast ion conductive LiTi 2 (PO 4) 3 (LTPO) is employed to modify the typical Li-rich cathode Li 1 · 2 Mn 0 · 56 Ni 0 · 17 Co 0 · 07 O 2 (LMNCO) via a sol-gel process combined with a two-step annealing treatment in this work. Serving as a physical separator, LTPO coating effectively depresses the side reactions at cathode-electrolyte interface and the transition-metal dissolution from LMNCO active material under harsh electrochemical environment. Meanwhile, LTPO layer with high ion conductivity could facilitate the interfacial Li+ diffusion during charge/discharge process. In addition, partial Ti4+ ions doped into LMNCO effectively elevate the oxygen electronegativity and restrain the excessive oxidization of lattice oxygen, thus stabilizing the crystal structure and alleviating the stress-strain propagation upon cycling. Electrochemical characterization results demonstrate that the LTPO-modified LMNCO cathode exhibits a superior capacity retention of 86.5 % after 400 cycles at room temperature and that of 73.7 % even under an elevated temperature of 45 °C after 250 cycles under 1C. This study provides a facile strategy for the surface modification of Li-rich layered-structure oxides, which also sheds light in enhancing electrochemical performances for various cathode materials. This work engineers NASICON-structure LiTi 2 (PO 4) 3 coating onto Li-rich Mn-based oxide via a facile sol-gel process combined with a two-step annealing treatment, simultaneously realizing gradient Ti-doping at interface region, thus to enhance the long-term performances of Li-rich cathode. [Display omitted] • Surface coating combined with gradient Ti-doping is designed to modify Li-rich cathode. • LTPO coating facilitates the interfacial Li + diffusion during charging/discharging process. • The LTPO-modified Li-rich cathode demonstrates the enhanced electrochemical performances. • The intrinsic mechanism of LTPO modification on Li-rich cathode is revealed in detail. [ABSTRACT FROM AUTHOR]

This work is innovative based on the construction of compressible nest-like spongy CNFs composite electrode to improve performance of flexible LIBs. Novelty gas-forming technique and efficient electrospinning fabricate unique macro sponge-like structure. It endows excellent electrochemical performance under compress state and superior compressible as well as recovery ability. The anode exhibits fast permeability and various pores morphology, and nest-like structure effectively relieve stress from expansion of particles in CNFs. Thus, the compressible spongy anode possesses long cycling life under deformation which could be hopefully applied in Flexible batteries. [Display omitted] • Spongy CNFs structure is available for compressible self-standing anode. • Spongy porous benefit electrolyte infiltration and ions diffusion. • The anodes exhibit compress recovery properties and excellent cycling ability. The state-of-the-art electronics promote the development of flexible and deformable batteries, which rely on design of advanced structure batteries and fabrication of suitable electrode materials. The current flexible electronics are generally limited by rigidity and nondeformable electrodes. Herein, this work reports an exceeding compressible spongy carbon nanofibers composite anode which was fabricated by electrospinning and gas-forming techniques. The abundant macro/micro porous and loss structure of spongy layers enable the composite electrode exhibited compressible capability and faster ions infiltration ability. And the nest morphology of spongy carbon nanofibers network promised stable conductivity and superior cycling performance of self-standing anodes. The compressible SnO 2 @spongy carbon nanofibers and SiO 2 @spongy carbon nanofibers self-standing anode exhibited outstanding cycling ability before 300 cycles under compressed state, with a capacity of 350 and 398 mA h g−1, respectively. Notably, the stress and strain of compressible spongy composite electrode are 370 kPa and 92%, separately, with recovery ability. The compressible spongy anode is highly recommended for flexible electrochemical energy storage devices and the novel gas-forming technique is a potential method for fabrication of multi morphology electrode. [ABSTRACT FROM AUTHOR]

In recent years, the driving range of electric vehicles (EVs) has been dramatically improved. But the large‐scale adoption of EVs still is hindered by long charging time. The high‐energy LIBs are unable to be safely fast‐charged due to their electrode materials with unsatisfactory rate performance. Thus it is necessary to summarize the properties of cathode and anode materials of fast‐charging LIBs. In this review, we summarize the background, the fundamentals, electrode materials and future development of fast‐charging LIBs. First, we introduce the research background and the physicochemical basics for fast‐charging LIBs. Second, typical cathode materials of LIBs and the method to enhancing their fast‐charging properties are discussed. Third, the anode materials of LIBs and the strategies for improving their fast‐charging performance are analyzed. Finally, the future development of the cathode materials in fast‐charging LIBs is prospected. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) nanostructure is currently the subject in the fields of new energy storage and devices. During the past years, a broad range of 2D materials represented by graphene have been developed and endow with excellent electrochemical properties. Among them, elemental 2D materials (Xenes) are an emerged material family for Li/Na‐ion battery (LIB/SIB) anodes. Compared with other 2D materials and bulk materials, Xenes may exhibit some great superiorities for Li/Na storage, including excellent conductivity, fast ion diffusion and large active sites exposure. In this review, we provide a systematic summary of the recent progress and achievements of Xenes as well as their applications in LIBs/SIBs. The broad categorization of Xenes from group IIIA to VIA has been concisely outlined, and the related details in syntheses, structures and Li/Na‐ion storage properties are reviewed. Further, the latest research progress of Xenes in Li/Na ion batteries are summarized, together with mechanism discussions. Finally, the challenges and prospects of Xenes applied to Li/Na ion battery are proposed based on its current developments. [ABSTRACT FROM AUTHOR]

In advancing battery technologies, primary attention is paid to developing and optimizing low-cost electrode materials capable of fast reversible ion insertion and extraction with good cycling ability. Sodium-ion batteries stand out due to their inexpensive price and comparable operating principle to lithium-ion batteries. To achieve this target, various graphene-based nanocomposites fabricate strategies have been proposed to help realize the nanostructured electrode for high electrochemical performance sodium-ion batteries. In this review, the graphene-based nanocomposites were introduced according to the following main categories: graphene surface modification and doping, three-dimensional structured graphene, graphene coated on the surface of active materials, and the intercalation layer stacked graphene. Through one or more of the above strategies, graphene is compounded with active substances to prepare the nanocomposite electrode, which is applied as the anode or cathode to sodium-ion batteries. The recent research progress of graphene-based nanocomposites for SIBs is also summarized in this study based on the above categories, especially for nanocomposite fabricate methods, the structural characteristics of electrodes as well as the influence of graphene on the performance of the SIBs. In addition, the relevant mechanism is also within the scope of this discussion, such as synergistic effect of graphene with active substances, the insertion/deintercalation process of sodium ions in different kinds of nanocomposites, and electrochemical reaction mechanism in the energy storage. At the end of this study, a series of strategies are summarized to address the challenges of graphene-based nanocomposites and several critical research prospects of SIBs that provide insights for future investigations. [ABSTRACT FROM AUTHOR]

Schematic diagram of the preparation of large layer-spacing VS 2 and ionic diffusion model. [Display omitted] Currently, the development of polyvalent ions battery systems are still restricted by lacking suitable cathode materials with high energy density and long cycle life attributing to sluggish kinetic mechanism and of polyvalent ions. Herein, an effective inter-layer scaling strategy is proposed by using a simple hydrothermal method. The super layer spacing VS 2 (∼1 nm) cathode dramatically improves electrochemical performance of zinc-ion batteries (ZIBs) and magnesium/lithium hybrid ion batteries (MLIBs). The specific discharge capacities of ZIBs and MLIBs are 450.7 and 488.8 mA h g−1 at current density of 0.1 A g−1 which are much higher than the same type of battery systems. Finally, the diffusion mechanism and the corresponding theoretical model is established by adopting first principles. In brief, the work provides an effective strategy for the large scale application of multivalent and hybrid batteries systems. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are gaining increasing attention as renewable cathode materials for Li‐ion batteries. However, COF electrodes reported so far still exhibit unsatisfying capacity due to their limited active site density and insufficient utilization. Herein, a new two‐dimensional polyimide‐linked COF, HATN‐AQ‐COF with multiple redox‐active sites for storing Li+ ions, was designed and fabricated from a new module of 2,3,8,9,14,15‐hexacarboxyl hexaazatrinaphthalene trianhydrides with a 2,6‐diaminoanthraquinone linker. HATN‐AQ‐COF possessing excellent stability, good conductivity, and a large pore size of 3.8 nm enables the stable and fast ion transport. This, in combination with the abundant redox active sites, results in a high reversible capacity of 319 mAh g−1 at 0.5 C (1 C=358 mA g−1) for the HATN‐AQ‐COF electrode with a high active site utilization of 89 % and good cycle performance, representing one of the best performances among the reported COF electrodes. [ABSTRACT FROM AUTHOR]

Lithium titanate composites with conducting additives are synthesized by the sol–gel method. As the conducting additives, carbon nanotubes (CNTs)—plain and heterosubstituted, graphene-like nanoflakes (CNFs), and the carbon coating formed by sucrose (S) pyrolysis are used. The introduction of carbon nanotubes considerably increases the reversible discharge capacity of composites including the case of high current densities. This occurs as a result of the formation of a three-dimensional network which sustains the fast transport of lithium ions and electrons between the particles of the anode material. Thus, at the current density of 200, 800, 1600, and 3200 mA/g, the reversible discharge capacity of the Li4Ti5O12/С/CNT is found to be 130, 107, 94, and 71 mA h/g, respectively. The use of CNFs as the conducting additive fails to considerably improve the properties of the anode material. [ABSTRACT FROM AUTHOR]

The urchin-like inverse spinel Mn doped NiCo 2 O 4 hierarchical microspheres deliver high reversible lithium ion storage capacity and excellent cyclability. [Display omitted] • Hierarchical Mn doped NiCo 2 O 4 (Mn-NiCo 2 O 4) is fabricated by a facile hydrothermal process. • Owning superior structural stability, Mn-NiCo 2 O 4 shows fast Li+ storage kinetics and high Li+ reversible capacity. • The assembled NCM(1 1 1)//Mn-NiCo 2 O 4 full cell exhibits long cycling lifespan. The ternary transition metal oxides are promising anode material for lithium-ion batteries (LIBs). However, their practical applications are greatly hindered by the poor conductivity and huge volume changes. To solve the issues, urchin-like inverse spinel manganese (Mn) doped NiCo 2 O 4 hierarchical microspheres were fabricated through a facile hydrothermal approach and subsequent annealing treatment. The as-obtained Mn-doped NiCo 2 O 4 hold microsphere and sharp fiber-shaped needle multilevel nanoscale architecture, which effectively shortened Li ions (Li+) transmission path and improved the conductivity. In addition, the hierarchical urchin-like Mn-doped NiCo 2 O 4 synthesized at annealing temperature (600 °C) manifested a larger capacity and better cycling performance by controlling the crystallinities and morphologies. As expected, it displays an outstanding cycling performance with a reversible capacity of about 945 mAh g−1 after 500 cycles at 2000 mA g−1. The kinetic analysis and galvanostatic intermittent titration technique (GITT) testing also verifies the superior pseudocapacitance contribution and fast elevated ion migration of Li+. Our work provides a promising design to develop suitable anode materials based on transition metal oxides for high-performance LIBs. [ABSTRACT FROM AUTHOR]

[Display omitted] • MXene was used as conductive substrate to reinforce the structural stability of Sb@C. • The MXene and carbon can spatially confine the Sb particles during cycling. • The MXene-Sb@C shows better lithium storage properties than the Sb@C composite. • The assembled Li ion full cell delivers a maximum energy density of 381.2 Wh kg−1. Antimony (Sb) is recognized as a potential anode material for lithium-ion batteries due to its high theoretical capacity and adequate working potential. However, its application is hindered by the significant volume expansion during lithiation and low intrinsic conductivity, leading to considerable capacity fading and reduced rate capability. Herein, a unique MXene-reinforced Sb@C (MSC) nanocomposite is constructed via in-situ growing Sb-MOF over the conductive MXene substrate, followed by annealing. MXene substrate and MOF-derived carbon layer coupling effectively creates a continuous and conductive framework, encapsulating Sb nanoparticles. This unique architecture mitigates volume expansion, prevents particle aggregation, and enhances interfacial charge transfer, significantly improving the lithium storage performance of the MSC nanocomposite over its Sb@C (SC) counterpart. The MSC nanocomposite achieves a high capacity of 625 mAh g−1 at 100 mA g−1, superior rate capability of 305 mAh g−1 at 10 A g−1, as well as excellent cycling stability with a capacity retention of 84.4 % over 2000 continuous cycles. Additionally, a lithium-ion full batteries with MSC anode and LiFePO 4 cathode demonstrates a capacity of 168.9 mAh g−1 at 100 mA g−1 and a maximum energy density of 381.2 Wh kg−1 based on the cathode mass, illustrating its promising potential for constructing high-performance lithium ion batteries. [ABSTRACT FROM AUTHOR]

With the continuous development of lithium‐ion batteries (LIBs), the electrochemical performance and safety of LIBs have become increasingly challenged recently. Therefore, research on high‐performance LIB separators has gradually attracted widespread attention. As an important component of lithium batteries, the diaphragm plays an important role in battery safety. Improving battery separator performance is an important way to improve batteries' safety and electrochemical performance. Herein, to prepare a new type of LIB separator, a preparation strategy in which polyimide (PI) nanofibers can be coaxially encapsulated by the inorganic boehmite (AlOOH) ceramics through an adsorption and complexation process is developed. This strategy involves immersing partially imidized PI nanofiber membranes into anhydrous aluminum chloride ethanol solution and dilute ammonia, where the adsorption−complexation and hydrolysis processes are completed. During the hydrolysis process, the PI nanofibers are evenly coated with AlOOH. The amount of AlOOH can be controlled easily by adjusting the concentration of the anhydrous aluminum chloride ethanol solution. After being encapsulated with AlOOH, the separator exhibits better mechanical properties, wettability, thermal stability, cycling durability, and a high capacity, along with faster ion transport speed. All excellent features prove that the PI@AlOOH composite nanofiber membrane is an advanced high‐performance LIB separator. [ABSTRACT FROM AUTHOR]

[Display omitted] An organic/inorganic hybrid coating consisting of molecular sieve (MS)/sulfonated melamine formaldehyde condensate (SMF) is fabricated on the polyethylene (PE) separator by a simple dip-coating process. The MS/SMF coating with high polarity enhances the electrolyte uptake of PE separator, and therefore favors higher ionic conductivity and Li+ transference number of separators. By regulating the ratio of MS/SMF, much higher Li+ transference number up to 0.5 can be obtained compared with the original PE separator (0.25). The PE separator possesses highest effective Li+ ionic conductivity when the ratio of MS/SMF is 3:1, which promotes more uniform Li+ deposition on the lithium metal surface for excellent lithium plating/stripping cycling stability up to 1000 h without any signs of short-circuit. Moreover, the functional PE separator possesses excellent H 2 O and HF capturing ability due to strong adsorption of MS and SMF for H 2 O and the scavenging of SMF for HF. The MS-SMF@PE separator-employed LiCoO 2 /Li unit cell shows superior C-rates capability and cycling performance, and no obvious lithium dendrite growth is found on the surface of lithium metal anode after cycling. [ABSTRACT FROM AUTHOR]

The present study investigated the role of SiOx in a rice-husk-derived C/SiOx anode on the rate and cycling performance of a Li-ion battery. C/SiOx active materials with different SiOx contents (45, 24, and 5 mass%) were prepared from rice husk by heat treatment and immersion in NaOH solution. The C and SiOx specific capacities were 375 and 475 mAh g−1, respectively. A stable anodic operation was achieved by pre-lithiating the C/SiOx anode. Full-cells consisting of this anode and a Li(Ni0.5Co0.2Mn0.3)O2 cathode displayed high initial Coulombic efficiency (~ 85%) and high discharge specific capacity, indicating the maximum performance of the cathode (~ 150 mAh g−1). At increased current density, the higher the SiOx content, the higher the specific capacity retention, suggesting that the time response of the reversible reaction of SiOx with Li ions is faster than that of the C component. The full-cell with the highest SiOx content exhibited the largest decrease in cell specific capacity during the cycle test. The structural decay caused by the volume expansion of SiOx during Li-ion uptake and release degraded the cycling performance. Based on its high production yield and electrochemical benefits, degree of cycling performance degradation, and disadvantages of its removal, SiOx is preferably retained for Li-ion battery anode applications. [ABSTRACT FROM AUTHOR]

The rational design of the unique morphology of particles has been considered as the key to improving the structural stability of spinel LiMn2O4 cathode materials for Li-ion batteries. Herein, a facile solid-state combustion process, combined with a Cr and Al co-doping approach, is proposed to prepare various LiCr0.01AlxMn1.99−xO4 (x ≤ 0.10) cathode materials with a good crystallinity. Cr and Al co-doping facilitates the formation of a single crystal truncated octahedral morphology. This endows the as-prepared LiCr0.01AlxMn1.99−xO4 with abundant {111} planes for Mn dissolution reduction and a few {100} and {110} planes for Li+ ion fast diffusion channels. Moreover, the introduction of Cr and Al elements with a stable electronic configuration further boosts the structural stability of the spinel LiMn2O4 owing to the relatively robust Al–O and Cr–O bonds compared with the Mn–O bond. Owing to these advantages, the optimal LiCr0.01Al0.05Mn1.94O4 delivers a good electrochemical performance with a high first discharge capacity of 118.5 mA h g−1 and a capacity retention of 70.8% after 1000 cycles at 1 C. Even at relatively high current rates of 15 and 20 C, a durable and prolonged cycling performance of up to 3000 cycles can be achieved. In addition, a high-temperature capacity retention of 72.1% is also maintained after 200 cycles at 5 C under 55 °C. This work provides potential candidates for developing long-life Li-ion batteries with a simultaneously high capacity. [ABSTRACT FROM AUTHOR]

[Display omitted] A low crystalline 1T-MoS 2 @S-doped carbon (MoS 2 @SC) composite was successfully synthesized via a facile hydrothermal process. The composite is comprised by few-layer 1T-MoS 2 nanosheets covered by an amorphous carbon layer with an expanded interlayer d-spacing of 1.01 nm. This structure is conducive to the fast transport of lithium-ions and volume accommodation during the charge–discharge process when the composite is applied as an anode material for LIBs. Additionally, the high conductivity and layered structure of 1T-MoS 2 also facilitate fast of ion/electron transport, contributing to the improvement of the electrochemical properties. Therefore, this material demonstrated a high rate performance and excellent cycling stability, with the capacities of 847 and 622 mA h g−1 achieved at the current densities of 0.2 A g−1 and 2 A g−1, respectively. Even at a larger current density of 2 A g−1, MoS 2 @SC delivered a high reversible capacity of 659 mA h g−1 with an average capacity loss of 0.006% per cycle after 500 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ti 2 Nb 10 O 29 cages were synthesized by self-sacrificing template method. • Ti 2 Nb 10 O 29 cages comprised of nanorod units exhibit perforated structure and big hollow center. • The special cage structure diminishes ion diffusion distance and relieves concentration polarization. • Lithium-ion battery with ultrahigh rate capability is achieved. Benefiting from large tunnel structure, zero strain feature, and excellent pseudocapacitive performance, Ti 2 Nb 10 O 29 was considered as a potential anode material for lithium-ion batteries (LIBs). Herein, Ti 2 Nb 10 O 29 cages comprised of nanorod units were elaborately designed. The mesoscopic structure could effectively shorten the ion diffusion pathway, and the big central electrolyte reservoir relieves the concentration polarization of electrolyte. Moreover, the perforated pore feature guarantees competent contact between electrolyte and framework. As the anode of LIBs, the mesoscopic Ti 2 Nb 10 O 29 cages deliver high reversible capacity (302.5 mAh/g) and rate capability (134.3 mAh/g at 30 A/g). This unique mesoscopic structure holds excellent potential for the electrode design of high-rate and long-life LIBs. [ABSTRACT FROM AUTHOR]

The sodium dual ion battery (Na‐DIB) technology is proposed as highly promising alternative over lithium‐ion batteries for the stationary electrochemical energy‐storage devices. However, the sluggish reaction kinetics of anode materials seriously impedes their practical implementation. Herein, a Na‐DIB based on TiSe2‐graphite is reported. The high diffusion coefficient of Na‐ions (3.21×10−11–1.20×10−9 cm2 s−1) and the very low Na‐ion diffusion barrier (0.50 eV) lead to very fast electrode kinetics, alike in conventional surface capacitive storage systems. In‐situ investigations reveal that the fast Na‐ion diffusion involves four insertion stage compositions. A prototype cell shows a reversible capacity of 81.8 mAh g−1 at current density of 100 mA g−1, excellent stability with 83.52 % capacity retention over 200 cycles and excellent rate performance, suggesting its potential for next‐generation large scale high‐performance stationary energy storage systems. [ABSTRACT FROM AUTHOR]

In this study, ZnSnO3/C nanofibers are successfully prepared using a simple electrospinning method and their morphology and electrical properties are characterized. The results show that the diameter of the ZnSnO3/C nanofibers is ~190 nm and they comprise ~25 nm particles. The lithium-ion battery (LIB) fabricated using the prepared ZnSnO3/C nanofibers exhibits a high initial specific capacity of 1411.7 mAh g−1 at a current density of 0.1 A g−1. Electrospun samples maintain a good specific capacity, owing to the unique structure of the ZnSnO3/C nanofibers, which provides both buffer spaces for the large volume expansion during repeated charge-discharge cycles and fast lithium-ion transport, resulting in excellent electrochemical performance. This study provides an effective method for the preparation of ZnSnO3/C nanofibers and a potential anode material for LIBs. ZnSnO3/C nanofibers are successfully synthesized via a simple electrospinning method, which maintains a good specific capacity during the charge discharge process with a large current density. These good performances are attributed to the unique structure of the ZnSnO3/C nanofibers, which provides both buffer spaces for the large volume expansion during repeated charge discharge cycles and fast lithium ion transport. [ABSTRACT FROM AUTHOR]

Nanoparticle-assembled Ti 2 Nb 10 O 29 porous microspheres coated by N-doped carbon layers (TNO@N–C-M) have been synthesized using ionic liquid 1-ethyl-3-methylimidazolium dicyanamide ([Emim]DCA) as carbon and nitrogen sources. Owing to the wide liquid range, low vapor pressure, and low surface tension of [Emim]DCA, the as-obtained N-doped carbon layers possess ultrathin thickness (~3 nm) and the primary TNO nanoparticles have ultrasmall sizes (20–30 nm). The synergistic effects from the particular structure lead to high electronic conductivity, fast ion/electron transport kinetics, and increscent pseudocapacitive contribution. Accordingly, the TNO@N–C-M anode has large discharge capacity (309.6, 262.2, 240.6, 216.5 and 204.5 mA h g−1 at 1, 5, 10, 20, and 30 C, respectively), good rate capacity (304.9 and 208.1 mA h g−1 at 1 and 30 C, respectively), and superior cycle stability (219.5 mA h g−1 after 500 cycles at 10 C). Also, the LiNi 0.5 Mn 0.3 Co 0.2 O 2 //TNO@N–C-M full cell also exhibits superior electrochemical properties with promising application prospect. [ABSTRACT FROM AUTHOR]

• ZnSe/NiSe 2 hollow hierarchical structure with rich selenium vacancies. • V-ZnSe/NiSe 2 @H-NC show a high-rate capacity and Long-cycle-life for LIBs and SIBs. • Excellent reversibility and high Li+/Na+ diffusion kinetics of V-ZnSe/NiSe 2 @H-NC. Transition metal selenides are perceived as promising anode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) due to their high theoretical specific capacity and structural diversity. Nonetheless, the poor structural stability and sluggish kinetics of metal selenides lead to unsatisfactory electrochemical performance. Herein, we have designed and synthesized ZnSe/NiSe 2 bimetallic selenides hollow hierarchical structure with rich selenium vacancies and homogeneous carbon layer (V-ZnSe/NiSe 2 @H-NC) as anode materials for both LIBs and SIBs. The unique hollow hierarchical morphology and carbon layer provide a large buffer area, leading to enhanced micro-structure stability during cycling. Furthermore, the ZnSe/NiSe 2 heterostructure not only offers the pseudocapacitance behavior but also gives rise to a large number of selenium vacancies, which will significantly improve the ion diffusion kinetics. The V-ZnSe/NiSe 2 @H-NC electrodes exhibit high reversible capacity and remarkable cycling stability in both LIBs and SIBs. The underlying electrochemical ion storage mechanisms are illustrated in detail by electrochemical kinetic analysis, ex-situ Raman, and density functional theory. This work provides a new angle to understand the mechanisms of enhancing performances in bimetallic selenides. [ABSTRACT FROM AUTHOR]

The performance of secondary batteries, of which the lithium‐ion battery is one of the most well known, depends not only on the active electrode materials but also on the electrode architecture. In particular, the reduction in electrode tortuosity is expected to enable batteries with high active material utilization and fast charging and discharging capabilities. Herein, it is shown how electrophoretic deposition can be used to produce electrodes comprising hybrid particles of cobalt(II,III) oxide‐coated rutile‐mica oriented in an out‐of‐plane fashion. Key to this process is a sacrificial anode which leads to charging of the flake‐shaped particles and formation of a holding layer cementing them perpendicular to the substrate. Moreover, the electrochemical performance of lithium‐ion battery anodes with out‐of‐plane and in‐plane oriented architectures is compared. The out‐of‐plane orientation of the flake‐like particles results in better utilization of active material, lower charge‐transfer impedance, and faster ion diffusion. Moreover, for a range of charge/discharge rates, the specific capacity is over three times higher in comparison to an electrode with the same material oriented in an in‐plane architecture. The approach to electrode structuring is both facile and scalable and can be readily applied in the future to produce other electrochemical energy storage device electrodes. [ABSTRACT FROM AUTHOR]

Li 2 O-2B 2 O 3 coated Li 4 Ti 5 O 12 anode with protected particle surface and fast ion transfer exhibit desired rate capability and cycling stability for lithium ion batteries. Li 2 O-2B 2 O 3 (LBO) ionic conductor with high conductivity plays an important role in boosting the rate performance and cycling stability of Li 4 Ti 5 O 12 (LTO) anode for lithium-ion batteries by preventing direct exposure of LTO to the electrolyte. Herein, the effect of LBO coating layer on lithium ion (Li+) storage performance is investigated in detail by adjusting the adding amount of LBO precursor dispersion. LTO coated with 2 wt% LBO achieves an optimum performance with a specific capacity of 172.9 mA h g−1 at a current density of 0.1 A g−1, an improved rate capability (specific capacity of 127.9 mA h g−1 is maintained when the current density is 20 times than 0.1 A g−1) and a remarkable cycling stability (capacity retention of 94.2% after 4000 cycles at 2.0 A g−1). These LBO-LTO composites are competitive and promising candidates for electrochemical energy storage and other applications. [ABSTRACT FROM AUTHOR]

Lithium ion cells that can be quickly charged are of critical importance for the continued and accelerated penetration of electric vehicles (EV) into the consumer market. Considering this, the U.S. Department of Energy (DOE) has set a cell recharge time goal of 10-15 min. The following study provides an investigation into the effect of cell design, specifically negative to positive matching ratio (1.2:1 vs. 1.7:1) on fast charging performance. By using specific charging procedures based on negative electrode performance, as opposed to the industrial standard constant current constant voltage procedures, we show that the cells with a higher N:P ratio can be charged to ~16% higher capacity in the ten-minute time frame. Cells with a higher N:P ratio also show similar cycle life performance to those with a conventional N:P ratio, despite the fact that these cells experience a much higher irreversible capacity loss, leading to a lower reversible specific capacity. [ABSTRACT FROM AUTHOR]

Hollow nanomaterials have attracted broad attention due to their geometric configuration with some special properties such as fast ion diffusion, and accommodating structural transformation. However, conventional approaches for preparing hollow nanostructure commonly need an additional template removal process, which is time‐consuming and may require some corrosive chemicals. Herein, a general template‐induced sulfuration method is presented which is applicable for preparing a broad set of hollow sulfides. Sulfur particles are synthesized, which are then used as both template and sulfurizing reagent. During the heating, the template is removed along with the sublimation of sulfur, meanwhile the sulfur vapors sulfurize the coated precursor, finally forming a hollow sulfide nanostructure. As a demonstrating case study, a hollow NiS2 nanostructure is prepared through the presented approach which is confirmed extendable for many other sulfides such as CoS2, Bi2S3, and Cu2S. Furthermore, the hollow NiS2 exhibits bifunctional properties using as Al‐ion battery cathode and Li‐ion battery anode with good electrochemical performance, such as a 1000‐cycles stable capacity at high current density of 5 A g−1, stable temperature‐endurable property, and well‐recoverable rate performance. [ABSTRACT FROM AUTHOR]

Summary: Hybrid metal oxide heterostructures have been considered as ideal and potential anode materials for lithium ion batteries (LIBs) due to their better electrochemical performances, such as reversible capacity, structural stability and electronic conductivity. Herein, we have demonstrated synthesis of NiCo2O4/BiVO4 heterostructures by simple hydrothermal strategy to construct hybrid xNiCo2O4/(1–x)BiVO4 heterostructures with four selected compositions, that is, x = 10%, 20%, 30% and 40%. XRD shows the phases of NiCo2O4 and BiVO4 and FE‐SEM data revealed strong interface coupling between NiCo2O4 nanowires and BiVO4 dendrites. Upon testing for electrochemical properties, the optimized composition of 30%NiCo2O4‐70% BiVO4 showed higher reversible capacity of 408.6 mAh/g at a constant current rate of 0.5 A/g after 1000 cycles with columbic efficiency around 99% suggesting potential electrode material for high‐performance LIBs. The higher capacity is mainly attributed to the large surface area which can provide more channels and locations for fast Li ion intercalation/de‐intercalation into electrode materials. Additionally, improved Li ion storage capacity with superior rate capability of BN‐30 electrode could be attributed to its lower charge‐transfer resistance. The dendritic and nanowire heterostructure novel system with good stable capacity for LIBs is hitherto unattempted. [ABSTRACT FROM AUTHOR]

Peanut-shaped porous ZnMn2O4 microparticles assembled by nanoparticles have been prepared by annealing treatment of the Zn1/3Mn2/3CO3 precursors synthesized via a solvothermal reaction in water-triethanolamine binary solvent. The volume ratio of water to triethanolamine remarkably affects the shape and particle size of the carbonate precursor. The monodisperse ZnMn2O4 microparticles with a length of ca. 1 µm and a width of ca. 0.5 µm are constructed by many interlinked nanoparticles with a size of ca. 50–90 nm. As anode materials for Li-ion batteries, the peanut-shaped ZnMn2O4 microparticles display an outstanding rate capability with a lithiation capacity of 579 mAh g−1 at 4 A g−1 and long-cycle performance with a reversible capacity of 797 mAh g−1 after 700 cycles at 0.5 A g−1. The significantly enhanced lithium storage properties benefit from the desired porous micro-/nanostructures with suitable particle sizes, which enable the fast diffusion for lithium ions and the structural integrity of the electrode upon cycling. [ABSTRACT FROM AUTHOR]

Binary transition‐metal oxides (BTMOs) with hierarchical micro–nano‐structures have attracted great interest as potential anode materials for lithium‐ion batteries (LIBs). Herein, we report the fabrication of hierarchical cauliflower‐like CoFe2O4 (cl‐CoFe2O4) via a facile room‐temperature co‐precipitation method followed by post‐synthetic annealing. The obtained cauliflower structure is constructed by the assembly of microrods, which themselves are composed of small nanoparticles. Such hierarchical micro–nano‐structure can promote fast ion transport and stable electrode–electrolyte interfaces. As a result, the cl‐CoFe2O4 can deliver a high specific capacity (1019.9 mAh g−1 at 0.1 A g−1), excellent rate capability (626.0 mAh g−1 at 5 A g−1), and good cyclability (675.4 mAh g−1 at 4 A g−1 for over 400 cycles) as an anode material for LIBs. Even at low temperatures of 0 °C and −25 °C, the cl‐CoFe2O4 anode can deliver high capacities of 907.5 and 664.5 mAh g−1 at 100 mA g−1, respectively, indicating its wide operating temperature. More importantly, the full‐cell assembled with a commercial LiFePO4 cathode exhibits a high rate performance (214.2 mAh g−1 at 5000 mA g−1) and an impressive cycling performance (612.7 mAh g−1 over 140 cycles at 300 mA g−1) in the voltage range of 0.5–3.6 V. Kinetic analysis reveals that the electrochemical performance of cl‐CoFe2O4 is dominated by pseudocapacitive behavior, leading to fast Li+ insertion/extraction and good cycling life. [ABSTRACT FROM AUTHOR]

Fast charging is thought to be the key to enable long-distance battery electric mobility and widespread adoption of battery electric vehicles. Herein, optimized 28 mAh three-electrode cells with lithium titanium oxide coated aluminum meshes as reference electrodes are used to analyze their charging performance potential. Lithium plating only occurs if the anode potential falls below 0 V versus Li/Li+, which has to be avoided during charging. Thus, current multistep protocols are derived to allow fast charging of the three-electrode cells without significantly increased aging for 300 cycles when compared to 1 C constant current--constant voltage charging. In contrast, it is shown that charging with an average current to the same state of charge in the same time is much more harmful. This average current exceeds the current limits at high states of charge as determined by the three-electrode measurements. Consequently, postmortem scanning electron microscopy images indicate the occurrence of lithium plating. After 300 aging cycles using the multistep or 1 C reference charging, the threeelectrode cells show a surprising charging performance increase which is linked to reduced overpotentials at the anode. The results demonstrate the suitability of this three-electrode cell design to determine aging-optimized fast charging current profiles. [ABSTRACT FROM AUTHOR]

Tailoring the electrode structure and morphology with short diffusion distance for fast ions transport is of significant to improve rate capability for advanced lithium-ion batteries. A novel architecture of hollow Co 3 O 4 nanocrystals in situ anchored on holey graphene is successfully fabricated, and individual hollow Co 3 O 4 nanocrystal is located around one etched hole on graphene sheets. This newly fabricated nanostructure is able to greatly shorten mass diffusion distance for enhancement of Li ion transport, resulting in the best rate performance among previously reported composites of Co 3 O 4 and graphene. This work reveals that high rate lithium-ion batteries can be achieved through constructing the hybrids of Co 3 O 4 nanocrystals on in situ etched holey graphene, while rendering fundamental for enhancement of mass transport rate by highly shortened ions diffusion distance in a nanostructured electrode to accomplish superior rate capability. Image 1 [ABSTRACT FROM AUTHOR]

Li4Ti5O12 (LTO) is one of the most promising high-power anodes for lithium ion batteries, but its large-current performance is still undermined due to relatively poor ion/electron transfer. In this work, we report a powerful hydrothermal method for fabrication of highly porous binder-free Li4Ti5O12 films, which show hierarchical structure composed of interconnected primary nanoparticles of 50-100 nm and secondary nanowalls. The lithium ion storage performance of designed Li4Ti5O12 films is thoroughly studied and demonstrated with excellent high-rate performance. The as-prepared Li4Ti5O12 films exhibit a high specific capacity of 146 mAh g-1 at the current density of 2 C. In view of good structural stability, a notable cycling stability is verified with a specific capacity of 130 mAh g-1 after 5000 cycles at 2 C. Our method provides a novel route for synthesis of other advanced anodes for application in the field of ultrafast energy storage. Highly porous binder-free Li4Ti5O12 films are synthesised via a hydrothermal method and exhibit a noticeable high-rate electrochemical performance as the anode of lithium ion batteries. [ABSTRACT FROM AUTHOR]

Silicon is a promising anode material for lithium-ion and post lithium-ion batteries but suffers from a large volume change upon lithiation and delithiation. The resulting instabilities of bulk and interfacial structures severely hamper performance and obstruct practical use. Stability improvements have been achieved, although at the expense of rate capability. Herein, a protocol is developed which we describe as two-dimensional covalent encapsulation. Two-dimensional, covalently bound silicon-carbon hybrids serve as proof-of-concept of a new material design. Their high reversibility, capacity and rate capability furnish a remarkable level of integrated performances when referred to weight, volume and area. Different from existing strategies, the two-dimensional covalent binding creates a robust and efficient contact between the silicon and electrically conductive media, enabling stable and fast electron, as well as ion, transport from and to silicon. As evidenced by interfacial morphology and chemical composition, this design profoundly changes the interface between silicon and the electrolyte, securing the as-created contact to persist upon cycling. Combined with a simple, facile and scalable manufacturing process, this study opens a new avenue to stabilize silicon without sacrificing other device parameters. The results hold great promise for both further rational improvement and mass production of advanced energy storage materials. Stabilizing silicon without sacrificing other device parameters is essential for practical use in lithium and post lithium battery anodes. Here, the authors show the skin-like two-dimensional covalent encapsulation furnishing a remarkable level of integrated lithium storage performances of silicon. [ABSTRACT FROM AUTHOR]

La 2 O 3 nanocoating endows LiNi 0.5 Mn 1.5 O 4 with a stable structure, thin SEI layers and fast lithium ions diffusion, boosting the lithium ion storage performance. • The cycling performance of LiNi 0.5 Mn 1.5 O 4 is highly enhanced by La 2 O 3 coating. • Voltage fade is introduced to evaluate the voltage stability of LiNi 0.5 Mn 1.5 O 4. • The effects of La 2 O 3 coating contents are systematically investigated. • The modified LiNi 0.5 Mn 1.5 O 4 possess a stable structure, thin SEI layers and fast lithium ions diffusion. In this work, a conformally interfacial nanocoating strategy is introduced to enhance the lithium ion storage performance of LiNi 0.5 Mn 1.5 O 4 (LNMO). Stable cycling of LNMO is achieved through La 2 O 3 coating at both room and elevated temperatures. A series of La 2 O 3 -coated LNMO composites with various coating contents ranging from 0 to 3 wt% is prepared, and their electrochemical behaviors are systematically investigated. Among them, the 2 wt% La 2 O 3 -coated LNMO cathode presents the best comprehensive lithium ion storage performance; for instance, it retains more than 75% capacity retention after 500 cycles at room temperature and 93% capacity retention after 50 cycles at an elevated temperature of 55 °C with 1C rate. Moreover, the modified samples show more stable plateau potential than the pristine one during the cycling process. It is believed that the introduction of the La 2 O 3 nanocoating layer can effectively suppress side reactions between electrode and electrolyte, thus maintaining stable structure of electrode material and reducing polarization during cycling. Our work provides an effective approach to improve the electrochemical stability of LNMO high-potential cathode for future large-scale applications of enhanced lithium ion batteries with high energy density and long cycle life. [ABSTRACT FROM AUTHOR]

Lithium ion batteries (LIBs) at present still suffer from low rate capability and poor cycle life during fast ion insertion/extraction processes. Searching for high‐capacity and stable anode materials is still an ongoing challenge. Herein, a facile strategy for the synthesis of ultrathin GeS2 nanosheets with the thickness of 1.1 nm is reported. When used as anodes for LIBs, the two‐dimensional (2D) structure can effectively increase the electrode/electrolyte interface area, facilitate the ion transport, and buffer the volume expansion. Benefiting from these merits, the as‐synthesized GeS2 nanosheets deliver high specific capacity (1335 mAh g−1 at 0.15 A g−1), extraordinary rate performance (337 mAh g−1 at 15 A g−1) and stable cycling performance (974 mAh g−1 after 200 cycles at 0.5 A g−1). Importantly, our fabricated Li‐ion full cells manifest an impressive specific capacity of 577 mAh g−1 after 50 cycles at 0.1 A g−1 and a high energy density of 361 Wh kg−1 at a power density of 346 W kg−1. Furthermore, the electrochemical reaction mechanism is investigated by the means of ex‐situ high‐resolution transmission electron microscopy. These results suggest that GeS2 can use to be an alternative anode material and encourage more efforts to develop other high‐performance LIBs anodes. [ABSTRACT FROM AUTHOR]

Potential electrolytes for lithium ion batteries (LIB) depicting high electrochemical stability and ionic conductivity still represents a great challenge. Herein, we investigate the reduction stability and Li+ cation interactions with substituted cyclic phospholanium (CylP5+) and pyrrolidinium (Pyr+) ionic liquids (ILs) with bis(trifluoromethanesulfonyl)imide (TFSI-) anion. The cations CylP5 + and Pyr+ are functionalized with varying chain lengths of alkyl and alkoxy substituents and their reduction potentials evaluated with respect to Li+/Li. CylP5 + cations, in general have better stability than Pyr+ based ILs, while the alkoxy substitution is found to lower the reduction stability compared to alkyl substituents in both ILs. Furthermore, the interaction energies between the substituent modified-cations (C), Li+ cation and the anion (A) were evaluated. The ion-pair (C-A) interaction energies on addition of Li+ cation is shown to decrease for both Pyr+ and CylP5 + cations with shorter alkoxy chain lengths, thereby implying faster diffusion of ions due to weaker interactions. Similarly, among the two cations, lowest ΔE were noted between alkoxy substituted [Li(CylP5)]2+ cation and TFSI-, signifying faster diffusion of ions in CylP5 + based electrolytes than that of Pyr+ based ILs. These results govern the synthesis of novel ILs with promising base cation and functionalization for LIB. [ABSTRACT FROM AUTHOR]

The spatial distribution and transport characteristics of lithium ions (Li+) in the electrochemical interface region of a lithium anode in a lithium ion battery directly determine Li+ deposition behavior. The regulation of the Li+ solvation sheath on the solid electrolyte interphase (SEI) by electrolyte chemistry is key but challenging. Here, 1 m lithium trifluoroacetate (LiTFA) is induced to the electrolyte to regulate the Li+ solvation sheath, which significantly suppresses Li dendrite formation and enables a high Coulombic efficiency of 98.8% over 500 cycles. With its strong coordination between the carbonyl groups (CO) and Li+, TFA− modulates the environment of the Li+ solvation sheath and facilitates fast desolvation kinetics. In addition, due to relatively smaller lowest unoccupied molecular orbital energy than solvents, TFA− has a preferential reduction to produce a stable SEI with uniform distribution of LiF and Li2O. Such stable SEI effectively reduces the energy barrier for Li+ diffusion, contributing to low nucleation overpotential, fast ion transfer kinetics, and uniform Li+ deposition with high cycling stability. This work provides an alternative insight into the design of interface chemistry in terms of regulating anions in the Li+ solvation sheath. It is anticipated that this anion‐tuned strategy will pave the way to construct stable SEIs for other battery systems. [ABSTRACT FROM AUTHOR]

Ta2O5 is one of the promising anode materials for lithium ion battery application undergoing conversion reaction in combination with an extrinsic pseudocapacitance property. We have synthesized Ta2O5 nanoparticles by hydrothermal method using and without using polyethylene glycol (PEG) as co-solvent. Ta2O5 nanoparticles were characterized by PXRD, SEM, EDAX, BET, and TEM analysis. Electrochemical characterizations like Cyclic voltammetry, galvanostatic charge-discharge process, and rate capability were studied for Ta2O5 NPs. A reversible capability of 130 mA h g−1 is retained after 85 cycles at 0.1C rate by Ta2O5 NPs synthesized using PEG, and reversible capability of 127 mA h g−1 is retained after 40 cycles at 0.1C rate by Ta2O5 NPs synthesized without using PEG. Polyethylene glycol as cosolvent induced enhanced porosity favoring the fast lithium ion transport and better reversible capacity upon cycling. [ABSTRACT FROM AUTHOR]

Silicon is a promising anode material with high capacity for lithium‐ion batteries (LIBs) but suffers from poor conductivity and large volume change during charge/discharge. Herein, by using two‐dimensional conductive MXene as a multifunctional binder instead of conventional insulating polymer binders such as poly(vinylidene fluoride) or carboxymethylcellulose sodium (PVDF and CMC, respectively), a free‐standing, flexible Si@C film was fabricated by simple vacuum filtration and directly used as anode for LIBs. In the MXene‐bonded Si@C film, MXene constructed a three‐dimensional conductive framework in which Si@C nanocomposites were embedded. Its loose and porous structure provided much space to buffer the large volume expansion of Si@C nanoparticles and thus led to significantly superior cycle stability compared with conventional CMC‐ and PVDF‐bonded Si@C electrodes. Moreover, the porous structure and the metallically conductive MXene offered fast ion transport and outstanding conductivity of the MXene‐bonded Si@C film, which were favorable for its rate performance. These results promise good potential of the MXene‐bonded Si@C film electrode for LIBs. [ABSTRACT FROM AUTHOR]

A facile yet efficient two‐step electrospinning calcination strategy is smartly developed to construct 1D hierarchical coral‐like CoTiO3/Co3O4/TiO2 hybrid nanobelts. The 1D coral‐like nanohybrid is homogeneously constructed from well‐dispersed CoTiO3 nanobelts and uniformly distributed secondary crystalline Co3O4/TiO2 nanoparticle building blocks. When evaluated as anodes for lithium‐ion batteries (LIBs), the hybrid CoTiO3/Co3O4/TiO2 nanobelt electrode exhibits a promising reversible capacity of 722.3 mAh g−1 at 100 mA g−1 after 250 cycles and has excellent cyclability with a capacity of 256.7 mAh g−1 after 1000 cycles at a current density of 2000 mA g−1. The imitating 1D coral‐like structural pattern is beneficial to alleviate the nanoparticle agglomeration and increase the contact area with the electrolyte, leading to the short diffusion path and facilitating the rapid transfer of lithium ions. The high‐level secondary nanobuilding blocks offer a large specific surface area, high surface‐to‐bulk ratio, and fast interfacial ion transport. Herein, it strongly sheds light on the elegant design concept of the hybrid for fabricating next‐generation advanced rechargeable LIBs. [ABSTRACT FROM AUTHOR]

Rylene imides (RIs) are attractive organic battery materials because of the inherent modularity of the molecules. While strong aggregation of RIs is disadvantageous for fast lithium‐ion transport in the organic active material, decreasing the solubility of the RIs in battery electrolytes is essential to avoid performance fading. Therefore, the design and synthesis of RIs for lithium batteries is a non‐trivial task that must, among other considerations, balance lithium‐ion transport in the solid material vs. low solubility by controlling aggregation and packing. We have chosen triphenylamine (TPA) as a substituent which disrupts the aggregation but maintains a low solubility due to increased aromaticity of TPA. We have synthesized three RIs with one, two, and four aromatic units in the core. All of them showed stable specific capacity over 300 charge‐discharge cycles. The batteries also showed specific capacities close to their theoretical capacities with 97–99 % coulombic efficiency. The maximum specific energy and specific power were 197 mWh g−1 and 37 mW g−1, respectively. [ABSTRACT FROM AUTHOR]

SnO2@C nanocomposites were synthesized using a citrate gel method in one step. Carbon has been used to increase the conductivity of pristine SnO2. The SnO2@C nanocomposites show nanoparticles sized in the range of 30–50 nm. A structural study by XRD shows the tetragonal rutile structure of SnO2. Furthermore, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirm the existence of SnO2 along with carbon. The electrochemical performance was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge–discharge measurements. The nanocomposite has been used as an anode material for lithium-ion batteries. Pristine SnO2 exhibited a discharge capacity of 1854 mA h g−1 and a corresponding charge capacity of 1038 mA h g−1 for the first cycle. The SnO2@C nanocomposite showed a discharge capacity of 2574 mA h g−1 and charge capacity of 1481 mA h g−1 for the first cycle. These results clearly show the effect of carbon incorporation in SnO2. Furthermore, the nanocomposite shows a discharge capacity as high as 725 mA h g−1 after 200 cycles at a current density of 50 mA g−1. Thus, the obtained capacity for the nanocomposites is much higher as compared to that for pristine SnO2, i.e., 119 mA h g−1 at 50 mA g−1 after 200 cycles. The higher capacity in the nanocomposites is due to the fast transport of electrons and easy transport of lithium ions due to the carbon in the nanocomposites. The SnO2@C nanocomposite anode exhibits superior cycling stability and rate capability due to its stable electrode structure. [ABSTRACT FROM AUTHOR]