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Lithium-ion batteries (LIBs) are greatly limited in their practical application because of their poor cycle performance, low conductivity and volume expansion. Herein, molten salts (MSs) FeCl3·6H2O-NMP with low temperature via simple preparation are used as the anode material of LIBs for the first time to break through the bottleneck of LIBs. The good fluidity and high self-healing of FeCl3·6H2O-NMP effectively avoid the collapse and breakage of the structure. Based on this feature, the initial discharge specific capacity reached 770.28 mA h g-1, which was more than twice that of the commercial graphite anode. After 200 cycles at a current density of 100 mA g-1, the specific capacity did not decrease rather it was found to be higher than the initial discharge specific capacity, reaching 867.24 mA h g-1. Besides, the good conductivity of MSs provides convenience for the removal and intercalation of Li+. The active H sites that can combine with lithium ions form LiH and provide capacity for LIBs. Density functional theory (DFT) calculation also provided theoretical proof for the mechanism of LIBs. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals (CNCs) are bioderived one-dimensional species with versatile surface chemistry and unique self-assembling behavior in aqueous solutions. This work presents a scientific approach to leverage these characteristics for creating CNC network templates and processing them to engineer a novel silicon (Si)-based material called silicon nano-quill (SiNQ) for energy storage applications. The SiNQ structure possesses a porous, tubular morphology with a substantial ability to store lithium ions while maintaining its structural integrity. The presence of Si suboxides in the SiNQ structure is demonstrated to be crucial for realizing a stable cycling performance. One of the defining attributes of SiNQ is its water dispersibility due to Si–H surface bonds, promoting water-based Si-graphite electrode manufacturing with environmental and economic benefits. The incorporation of only 17 wt% SiNQ enhances the capacity of graphitic anodes by ∼2.5 times. An initial coulombic efficiency of 97.5% is achieved by employing a versatile pre-lithiation. The SiNQ-graphite anodes with high active loading, when subjected to accelerated charging/discharging conditions at 5.4 mA cm−2, exhibit stable cycling stability up to 500 cycles and average coulombic efficiency of >99%. A generalized physics-based cyclic voltammetry model is presented to explain the remarkable behavior of SiNQs under fast-charging conditions. [ABSTRACT FROM AUTHOR]

The binary composite, ZnSnO3 microcubes (ZSO MC) homogeneously parceled in an N-doped carbon nanofiber membrane (ZSO@CNFM), was synthesized via a mild hydrothermal, electrospinning and carbonization process as a flexible lithium-ion battery (LIB) anode material. The unique carbon-coating layer architecture of ZSO@CNFM not only plays a crucial role in alleviating the volume change of ZSO MC during lithium ion insertion/extraction processes, but also constructs a three-dimensional (3D) transport network with the help of interconnected carbon nanofibers (CNFs) to ensure the structural integrity of the material and promote the electrochemical reaction kinetics. Due to its good flexibility characteristics, the as-prepared ZSO@CNFM can be directly adopted as an anode material for LIBs without the use of copper foil, conductive carbon black and any binder. Electrochemical surveying results manifest that the optimal ZSO@CNFM electrode displays excellent cycling stability (582.6 mA h g−1 after 100 lithiation/delithiation cycles at 100 mA g−1), high coulombic efficiency (CE, 99.6% at 100th cycles), and superior rate performance (349.5 mA h g−1 at 2 A g−1). The good electrochemical properties can be ascribed to the synergistic effect of the high theoretical specific capacity of ZSO MC, favourable stability of the carbon substrate, the open structure of ZSO@CNFM and the 3D continuous highly conductive framework for rapid electron/ion transfer. [ABSTRACT FROM AUTHOR]

Due to its remarkably high specific capacity of 3860 mA h g−1 and low reduction potential (−3.04 V vs. SHE), lithium metal has been identified as an ideal anode candidate for high-energy density lithium-ion cells. However, the growth of lithium dendrites caused by the deposition of lithium metal can affect the charge and discharge behavior of a cell and lead to short circuit, which is a safety concern and hinders its practical applications. Here, we prepare a composite separator polypropylene-Li1+xAlxTi2−x(PO4)3-indium tin oxide (PP–LATP–ITO) via a simple slurry coating method. The coating of LATP-ITO demonstrates unique advantages of Li-ion deposition as well as interfacial chemistry. Firstly, lithiophilic PP-ITO helps to reduce the energy barrier for Li deposition. In addition, the three-dimensional ion channels can regulate the transport of lithium ions and induce uniform Li metal plating and stripping. Furthermore, the in situ formed interface comprising of a Li–In alloy, Li3PO4 and LiF enables stable interfacial chemistry. As a result, compared with the PP separators, the voltage stability of the composite separators in Li–Li symmetric cells is greatly improved during the charge and discharge cycling. In addition, LCO/Li cells with the composite separator PP–LATP–ITO exhibit a higher specific capacity (140 mA h g−1) and good capacity maintenance during cycling. This work proposes a separator coating strategy that can inhibit dendrite formation and stabilize the lithium metal interface. [ABSTRACT FROM AUTHOR]

Rational design and synthesis processes are very important for giving a product an excellent performance. Sn-based anode materials with a high theoretical capacity and suitable working potential usually suffer from severe capacity fading due to their inferior electronic conductivity and obvious volumetric variations, hindering their practical applications. Herein, hierarchical N doped graphene-supported SnO2/Zn2SnO4 (SnO2/Zn2SnO4-NG) is successfully prepared via a facile approach forming a 3D hierarchical configuration. As an anode for lithium-ion batteries, the SnO2/Zn2SnO4-NG anode can reach a high reversible capacity (837 mA h g−1 after 300 cycles at 0.2 A g−1) and rate capability (403 mA h g−1 at 5 A g−1) but also show extraordinary durability. Furthermore, it exhibits an impressive rate performance and maintains superior cycling stability. Such significantly enhanced electrochemical performances of the SnO2/Zn2SnO4-NG anode can be attributed to the unique structural design, which can not only effectively reduce the stress from the discharging/charging process and maintain the structural stability of the electrode during cycling but also alleviate aggregation of the active materials and facilitate electrolyte/ion transport. Meanwhile, Zn2SnO4 can greatly improve the electrical conductivity (confirmed by DFT calculations), and SnO2/Zn2SnO4 can create more active sites for lithium storage. This work thus verifies the great potential of the SnO2/Zn2SnO4-NG composite for applications as a high-performance anode material in next-generation Li storage. [ABSTRACT FROM AUTHOR]

Uncontrollable lithium dendrite growth which typically results in poor cycling stability and safety issues remains a great challenge for lithium metal batteries. Herein, we report a novel separator modification strategy by using polydimethylsiloxane (PDMS) to functionalize a glass fiber separator to inhibit dendrite growth. The PDMS-modified separator not only acts as a mechanical barrier but also promotes the desolvation of lithium ions. Consequently, Li/Li symmetric cells with optimal PDMS-modified separators are able to stably cycle for more than 1200 hours at 2 mA cm−2 with a stable polarization voltage (about 60 mV). Moreover, with the assistance of the functionalized separator, the assembled Li/LiFePO4 full cell can impressively achieve capacity retention up to 82.5% and a coulombic efficiency of ∼99.4% after 200 cycles at 1.0 C. The PDMS functionalization strategy provides a simple and efficient approach for developing safe and high-performance lithium metal batteries. [ABSTRACT FROM AUTHOR]

SiOx is one of the most promising anode materials for lithium-ion batteries (LIBs), due to its high theoretical capacity and low cost. However, the huge volume expansion and low electron/ion diffusion rate hinder its further commercial applications. Herein, a simple molecular polymerization method is developed to synthesize N,P co-doped SiOx–C composites (denoted as SiOx–C@CNT), in which SiOx and carbon are uniformly dispersed at the atomic level, and the embedded carbon nanotubes improve the lithium ion diffusion kinetics. Benefiting from the unique structure, the SiOx–C@CNT composites exhibit a high reversible capacity of 848 mA h g−1 at 0.1 A g−1 and long cycling stability (84.0% capacity retention after 1500 cycles). More impressively, the LiCoO2∥SiOx–C@CNT full battery also exhibits stable cycle life (only 4.7% capacity loss after 300 cycles at 1 C). These results show the application potential of the SiOx–C@CNT anode in LIBs. [ABSTRACT FROM AUTHOR]

Single-phase magnesium molybdate, MgMoO4, is successfully synthesized by a facile sol-gel method. Attributed to the multielectron reaction and the synergistic effect of the elements molybdenum (Mo) and magnesium (Mg), the MgMoO4 electrode exhibits excellent electrochemical properties. After activation, benefiting from the decrease in particle size and the uniform nanosphere morphology, the MgMoO4 electrodes can deliver a stable high specific capacity of about 1060 mA h g−1 at a current density of 100 mA g−1 after 600 cycles. Based on the important role of the activation process, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and scan rate cyclic voltammetry (CV) measurement methods were employed to reveal the effect of the activation process on the electrochemical behavior of the electrode material. Furthermore, by combining the in situ X-ray diffraction (XRD) and ex situ X-ray photoelectron spectroscopy (XPS) results, we illustrate the lithium storage mechanism of the MgMoO4 electrode in detail. [ABSTRACT FROM AUTHOR]

Developing carbon-based nanomaterials with high capacity and stable structure as anode materials is of great significance for practical application in electronic devices. Herein, we report a facile self-template strategy to prepare hollow porous nitrogen-doped carbon embedded with ultrafine Co nanoparticles (Co@NC) based on the abundant hydroxyl functional groups on the surface of polydopamine (PDA) that can effectively anchor metal ions. The unique hollow porous structure affords large surface areas, adequate internal void space and short ion transport channels. Ultrafine Co nanoparticles embedded into hollow porous nitrogen-doped carbon offer good electronic conductivity and provide rich active sites for lithium ion adsorption (pseudocapacitance behavior) through electron transfer from metal to carbon. As the anode, Co@NC exhibited excellent cycling stability (627.5 mA h g−1 after 300 cycles at 0.5 A g−1) and remarkable rate performance (233.6 mA h g−1 at 5 A g−1). Benefiting from the unique design of the structure, Co@NC manifested a prospective anode material for stable, safe and high capacity lithium storage. Our work provides an effective strategy to synthesize hollow porous carbon embedded with ultrafine Co nanoparticles for enhancing the electrochemical performance of lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Rational engineering of the microstructure and interfacial properties of nano-metal oxides materials is critical to realize their practical use in batteries. This work reports a detailed study on how structural and chemical interplay in a robust 3D crumpled MXene protected SnO2 core–shell system contributes to performance as an anode in lithium-ion batteries. Our results show that the compact conductive MXene shell can provide robust protection against the large volume change and aggregation of SnO2, providing excellent structural stability. Further analyses show that rich surface groups on the MXene can not only enable strong interfacial interactions through Sn–O–Ti bonds to grant electrical contacts, but also provide a pseudocapacitive contribution for fast and stable lithium storage. Furthermore, a conformal SEI formed outside the MXene can build a stable protective interface and prevent further consumption of electrolyte simultaneously. As a result, the SnO2@MXene composite delivered a high specific capacity of 829.4 mAh g−1 at a current density of 0.2 A g−1, and exhibited an excellent cycling stability (533.9 mAh g−1 after 500 cycles at 1 A g−1). The strategy reported here for synthesizing a core–shell MXene based material can be promising for the development of high-performance anode materials for next-generation LIBs. [ABSTRACT FROM AUTHOR]

Ilmenite FeTiO3 has the advantage of high theoretical capacity and abundant sources as an anode material for lithium-ion batteries (LIBs). However, it suffers inferior rate capability caused by the aggregation of particles. To solve this problem, FeTiO3 nanoparticles embedded in porous CNTs were developed by the sol–gel route and subsequent calcination. The unique hybrids have a uniform distribution of FeTiO3 nanoparticles (5–20 nm) in the carbon matrix. Electrochemical tests prove that the porous FeTiO3/C hybrid nanotubes deliver a high capacity of 612.5 mA h g−1 at 0.2 A g−1 after 300 cycles. Moreover, they present remarkable rate capability and exceptional cycling stability, possessing 163.8 mA h g−1 at 5 A g−1 for 1000 cycles. The enhanced electrochemical performance of the FeTiO3/C hybrid is derived from the shortened Li+ transport length, good structure stability and conductive carbon matrix, which simultaneously solves the major problems of pulverization and agglomeration of FeTiO3 nanoparticles during cycling. [ABSTRACT FROM AUTHOR]

N-doped three-dimensional carbon nanostructured materials were obtained by calcinating hierarchical porous IRMOF-3 materials, and were fabricated in the presence of citric acid as a modulator via the conventional synthetic protocol, at 900 °C in an Ar atmosphere. The resultant carbon materials were used as anode materials for lithium ion batteries, and exhibited excellent lithium storage capacity and cycling stability and maintained a capacity of about 555 mA h g−1 at the current density of 0.2 A g−1 after 100 cycles. [ABSTRACT FROM AUTHOR]

Transition metal oxides are widely regarded as one of the most promising candidates for lithium-ion battery (LIB) anodes. However, the mechanisms of irreversible reactions occurring during the charging/discharging process are still controversial. In this study, the atomic structural transitions of the MnO@C anode upon lithiation/delithiation at the first cycle of charging and discharging are elucidated. Based on the quantities of Li embedded and released in different states, the anisotropy of the crystal plane of lithiation/delithiation in MnO is directly observed. We determine that lithium ions can be completely inserted into/extracted from MnO(220), while this cannot be achieved in MnO(200), which is the main reason for capacity degradation. This study reveals the reaction mechanisms and structural evolution in the electrochemical reactions of MnO@C anode materials during lithiation and delithiation. Additionally, it also provides guidance for the fabrication and optimization of MnO-based materials for LIBs in the future. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) few-layer MXene nanosheets have attracted extensive attention due to their great potential for high-rate energy storage devices, but a simplified method to synthesize these structures with good cycling and rate performances is still a challenge for the MXene family. In this work, a one-step method to synthesize 2D few-layer niobium carbide (Nb2CTx) MXene nanosheets by etching Nb2AlC powder is reported for the first time. A sample of the few-layer Nb2CTx electrode shows a high specific capacity of 354 mA h g−1 at 0.05 A g−1 with a long cycling lifetime. The specific capacity can be stabilized at 225 mA h g−1 after 800 cycles at 1.0 A g−1. The one-step synthesis of unassisted few-layer Nb2CTx MXene nanosheets paves the way for the exploration of Nb2CTx-based composite materials and applications. [ABSTRACT FROM AUTHOR]

Commercially available Li2O2 was proposed as a cathode additive in commercialized LiNi0.33Co0.33Mn0.33O2 (NCM) cathodes to offset the initial Li loss. Li2O2 can be decomposed substantially under catalysis of NCM and leaves almost no remnants after the Li compensation. [ABSTRACT FROM AUTHOR]

Nanostructured Li4Ti5O12 (LTO) as a promising anode material in lithium-ion batteries (LIBs) has shown excellent yet morphology-dependent performance in LIB operations. However, the structural origin that influences the material performance at the microscopic level remains unclear. Here, using combined in situ Raman spectroscopy and synchrotron X-ray diffraction, we comparatively investigated the structural stability of two nanostructured LTO materials with different morphologies by application of external pressure up to 27 GPa. In particular, nanoflower-like Li4Ti5O12 spheres (LTO-1) and Li4Ti5O12 nanoparticles (LTO-2) were subjected to high pressures using diamond anvil cells and their structural evolutions were characterized upon compression and decompression. Raman measurements show that both LTO materials undergo pressure-induced structural disorder but with different reversibilities upon decompression. X-ray results further confirmed the Raman measurements, and also allowed the quantitative analysis of pressure dependence of the crystal structures. Structural refinements of the diffraction patterns yield morphology-dependent bulk moduli of the two LTO materials, which reveal critical information about the intrinsic lattice strain and vacancies. These different structural characteristics, when compared with another spinel structure of lithiated titanium dioxide, allow the interpretation of the different performance between LTO-1 and LTO-2 for LIB operations. This study thus contributes to the understanding of the important factors that may influence the electrochemical performance and help with the design of new LTO-based anode materials for LIBs. [ABSTRACT FROM AUTHOR]

Rutile TiO2 embedded in carbon submicron-tablets (TiO2/C) with a “blueberry muffin” morphology was fabricated via a two-step pyrolysis from a metal–organic framework precursor. Such a unique structure of the TiO2/C submicron-tablets provides the ideal anode characteristics (high reversible capacity, superior rate capability and excellent long-term cycling stability) for fast rechargeable lithium ion batteries. [ABSTRACT FROM AUTHOR]

Hollow Mn2O3 microspheres have been synthesized by a simple and easy-to-adopt solvothermal method, facilitated by ethanol to obtain the phase pure product at 600 °C. Herein, the ascorbic acid aided inside-out Ostwald ripening promotes the formation of porous microspheres with a hollow interior surface, which is desirable to allow faster transport of lithium ions and to accommodate the volume changes associated with the Mn2O3 anode, especially upon extended cycling. Further, an appreciable high surface area of 426.6 m2 g−1 has been calculated from BET analysis, which is in favour of imparting excellent electrochemical properties that include high reversible capacity, good cycling stability and acceptable rate capability. Interestingly, Mn2O3 hollow microspheres exhibit 425 mA h g−1 under the influence of 1 A g−1 current density, thus qualifying itself as a high rate anode material, bestowed with the added advantage of appreciable high capacity, extractable under nominal current densities. For instance, without requiring the formation of composite, the as-received Mn2O3 anode delivers a steady-state capacity of 760 mA h g−1 at 50 mA g−1 and 610 mA h g−1 at 100 mA g−1, especially after completing 100 cycles. The synergistic advantage of the microspheres containing hierarchically arranged nanostructures and the hollow interior nature with better uptake of the electrolyte results in obtaining promising electrochemical performance from the currently synthesized Mn2O3 anode. [ABSTRACT FROM AUTHOR]

Uniform amorphous vanadium oxide films were coated on graphene via atomic layer deposition and the nano-composite displays an exceptional capacity of ~900 mA h g-1 at 200 mAg-1 with an1 excellent capacity retention at 1 A g-1 after 200 cycles. The capacity1 contribution (1161 mA h g-1) from vanadium oxide only almost reaches its theoretical value. [ABSTRACT FROM AUTHOR]

ZnFe2O4/C hollow spheres have been synthesized viaa facile solvothermal route using low cost raw materials. The resulting composite showed a very high specific capacity of 841 mAh g−1after 30 cycles and good rate capability. [ABSTRACT FROM AUTHOR]

A facile process was developed to synthesize MoS2/graphene nanosheet (GNS) composites by a one-step in situsolution-phase method. These MoS2/GNS composites therefore exhibit extraordinary capacity, i.e., up to 1300 mA h g−1, and excellent rate capability and cycling stability as an anode material for lithium ion batteries. [ABSTRACT FROM AUTHOR]