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In this work, the commercial detonation nanodiamonds (DNDs) are introduced to the anodes of lithium ion battery (LIBs) consisting of anatase titanium dioxide (TiO2) and synthesized graphite by a microwave treatment process. The compound TiO2/DND/graphite anodes are favorable for improving the LIB performance, where the LIBs have lithium storage capacities of 540 mA h g−1 at 0.5 C after 100 cycles and 300 mA h g−1 at 5 C after 1000 cycles, which are greatly higher than the theoretical data (168 mA h g−1) from TiO2 anode alone. The high capacity, as well as excellent cycling performance and stability of the LIBs, are attributed to the synergistic effect of DND (larger surface area, low expansion, high lithium adsorption capacity, chemical inertness), TiO2 (high Li+ insertion/extraction voltage, robust structural stability, lower volumetric expansion) and the improved ionic conductivity of the anode with additional fabricated graphitic powders. [ABSTRACT FROM AUTHOR]

Reasonably designing and synthesizing advanced electrode materials is significant to enhance the electrochemical performance of lithium ion batteries (LIBs). Herein, a metal–organic framework (MOF, Mil‐125) was used as a precursor and template to successfully synthesize the porous mooncake‐shaped Li4Ti5O12 (LTO) anode material assembled from nanoparticles. Even more critical, SmF3 was used to modify the prepared porous mooncake‐shaped LTO material. The SmF3‐modified LTO maintained a porous mooncake‐shaped structure with a large specific surface area, and the SmF3 nanoparticles were observed to be attach on the surface of the LTO material. It has been proven that the SmF3 modification can further facilitate the transition from Ti4+ to Ti3+, reduce the polarization of electrode, decrease charge transfer impedance (Rct) and solid electrolyte interface impedance (Rsei), and increase the lithium ion diffusion coefficient (DLi), thereby enhancing the electrochemical performance of LTO. Therefore, the porous mooncake‐shaped LTO modified using 2 wt % SmF3 displays a large specific discharge capacity of 143.8 mAh g−1 with an increment of 79.16 % compared to pure LTO at a high rate of 10 C (1 C=170 mAh g−1), and shows a high retention rate of 96.4 % after 500 cycles at 5 C‐rate. [ABSTRACT FROM AUTHOR]

Accurate and fast prediction of the remaining useful life of lithium (Li) ion batteries is an important requirement for successful electrification of automobiles. Consequently, there is a growing interest in the development of reduced‐order models. The existing reduced‐order electrochemical models can be used to predict battery performance (state of charge [SoC], terminal voltage) when the current through the battery is known a priori. Therefore these models cannot be used for studying the constant voltage (CV) mode of the constant current‐CV (CC‐CV) charging protocol, which is a common battery charging mechanism. In this work, we propose a reduced‐order electrochemical model to estimate the battery SoC under CC‐CV charging conditions, along with an analytical expression to approximate the CV mode charging time. We further propose a framework that accounts for the influence of the battery state of health (SoH) on the battery SoC during an operating cycle and vice‐versa. The proposed framework for estimating the battery SoC and SoH in a coupled manner shows good comparison with a first principles electrochemical model for CC‐CV charging conditions. This model can be used to study battery ageing and it can find applications in real‐time state estimation, charge protocol optimization, and battery design. [ABSTRACT FROM AUTHOR]

Due to the large reversible capacity, high operating voltage and low cost, layered ternary oxide cathode materials LiNixCoyAl1−x−yO2(NCA) and LiNixCoyMn1−x−yO2(NCM) are considered as the most potential candidate materials for lithium‐ion batteries (LIBs) used in (hybrid) electric vehicles (EVs). However, next‐generation long‐range EVs require a high specific capacity (around 203 mAh·g–1at 3.7V) at the cathode active material level, which is not provided with current commercially layered ternary oxide cathodes. Increasing the operating voltage is an effective method to improve the specific capacity of the cathode and the energy density of the battery, but the high operating voltage also causes a lot of problems, such as cation mixing and phase transformation, electrolyte decomposition, transition metal dissolution and microcracks. So far, researchers have carried out a lot of works to solve these issues. Surface coating, element doping and the design of electrolytes have been proved to be effective solutions. In this review, the failure mechanisms and modification methods of high‐voltage layered ternary oxide cathode materials are summarized, which could provide valuable information to the research of high‐voltage layered ternary oxide cathode materials in basic science and industrial production. [ABSTRACT FROM AUTHOR]

Due to the large reversible capacity, high operating voltage and low cost, layered ternary oxide cathode materials LiNixCoyAl1−x−yO2(NCA) and LiNixCoyMn1−x−yO2(NCM) are considered as the most potential candidate materials for lithium‐ion batteries (LIBs) used in (hybrid) electric vehicles (EVs). However, next‐generation long‐range EVs require a high specific capacity (around 203 mAh·g–1at 3.7V) at the cathode active material level, which is not provided with current commercially layered ternary oxide cathodes. Increasing the operating voltage is an effective method to improve the specific capacity of the cathode and the energy density of the battery, but the high operating voltage also causes a lot of problems, such as cation mixing and phase transformation, electrolyte decomposition, transition metal dissolution and microcracks. So far, researchers have carried out a lot of works to solve these issues. Surface coating, element doping and the design of electrolytes have been proved to be effective solutions. In this review, the failure mechanisms and modification methods of high‐voltage layered ternary oxide cathode materials are summarized, which could provide valuable information to the research of high‐voltage layered ternary oxide cathode materials in basic science and industrial production. [ABSTRACT FROM AUTHOR]

The application of metal oxides and sulfides for lithium‐ion batteries (LIBs) is hindered by the limited Li+ diffusion kinetics and inevitable structural damage. Pseudocapacitance for electrochemical lithium storage provides an effective and competitive solution for developing electrode materials with large capacity, high rate capability, and stability. Herein, a composite composed of VS4 nanoplates tightly bound to carbon nanotubes (VS4/CNTs) is developed to demonstrate pseudocapacitance‐assisted lithium storage. The texture of the assembled VS4 nanoplates supplies efficient electrolyte/ion diffusion, as well as exposed surface for pseudocapacitive behavior. The effective coupling between VS4 and CNTs ensures fast electron transfer and high stability. The VS4/CNTs anode exhibits high capacity of 1144 mAh g−1 at 0.1 A g−1, superior cycling stability (capacity retention of 100 % at 1 A g−1 after 400 cycles), and good rate capability. The pseudocapacitive behavior plays an important role in determining the excellent electrochemical properties, contributing to the increased charge rate and reaching as high as 42 % of the total charge at a scan rate of 1 mV s−1. This study demonstrates the potential application of metal sulfides with pseudocapacitive contribution in LIBs. [ABSTRACT FROM AUTHOR]

Silicon, an anode material for lithium ion batteries, has the highest theoretical specific capacity (∼ 4 2 0 0  mAh/g). The actual lithium storage capacity of ∼ 3 5 7 9  mAh/g is about 10 times that of the graphite anode materials class. This study involves magnesium heat reduction of the SiO2 preparation of silicon carbon composites. The Si/SiC composite shows a high initial specific capacity of 1406.7 mAh/g with a current density of 0.1 A/g. The morphology and pore size inherited from the SiO2 aerogel counteracts the volume expansion during the lithiation/delithiation process. This paper provides an articulate methodology for designing silicon anode material for high-performance rechargeable lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Rechargeable lithium ion batteries have spurred intense research to resolve the ever-increasing energy and environmental issues due to their efficient high energy density. Herein we demonstrate a simple pyrolysis route to fabricate novel hierarchical B-doped tubular carbon nanostructures. The unique tubular nanostructures along with B-doped effect could represent a high activity for surface-dependent electrochemical reaction processes. Experimental results reveal that the as-synthesized B-doped carbon nanotube show excellent electrochemical performances for lithium storage application. The B-doped carbon nanotube could deliver a high initial discharge capacity (2862.8 mAh g−1) with Coulombic efficiency of 43.91% at 100 mA g−1 current density. Even at a higher current density of 500 mA g−1, the B-doped carbon nanotube could exhibit an enhanced initial discharge capacity of 1800.9 mAh g−1, and the reversible lithium storage capacity still retains at 851.3 mAh g−1 over 100 cycles, suggesting a good cycling stability. The excellent electrochemical properties of the as-synthesized B-doped carbon nanotube could be ascribed to the unique tubular architecture, which could offer large active surface with more lithium-insertion channels and significantly reduce lithium ion diffusion distance. The cost-efficient synthesis and excellent lithium storage properties make the B-doped carbon nanotube as a promising anode material for high-performance lithium ion batteries. Image 1 • Novel hierarchical B-doped tubular carbon nanostructures have been fabricated. • B-doped CNTs show excellent electrochemical performances for lithium storage application. • B-doped CNTs deliver a high initial discharge capacity (2862.8 mAh g−1) at 100 mA g−1 current density. • The reversible lithium storage capacity of B-doped CNTs still retains at 851.3 mAh g−1 over 100 cycles. [ABSTRACT FROM AUTHOR]

Polypyrrole (PPy) used as popular coatings can improve the electrochemical performance of electrodes greatly; however, uniform coatings of PPy on nanostructures is a challenging task in a solution system. Substitution for liquid phase polymerization reaction, herein a developed evaporation method is reported to make pyrrole vapor in situ polymerization on CuO arrays for the uniform PPy coatings. With the help of this uniform PPy coatings, the unique structure of arrayed CuO film can well maintain the stability of mechanical structures and has rapid transmission of lithium ions and electrons during charge/discharge processes, hence harvesting a high lithium storage. Electrochemical tests indicate that PPy can not only enhance the specific capacities of CuO anodes greatly but also improve the cyclic stability at a high-current density. The specific capacity of the CuO@PPy integrated anode can be up to 561 mAh g−1 at 1 C after 100 cycles, which is increased by almost 33% than that of the pure CuO anode. [ABSTRACT FROM AUTHOR]

The properties of lithium ion battery largely depend on the structure of active materials. In the present work, CoFe _2 O _4 nanowire arrays /Cu foam three-dimensional integrated electrode (denoted as CFO/Cu-foam NWAs) was firstly designed and synthesized via a simple hydrothermal method follow annealing as a binder-free anode for lithium ion battery. The CoFe _2 O _4 nanowires with diameter of 50–100 nm are uniformly anchored on the porous conductive substrate. Lithium ion battery based on the CFO/Cu-foam NWAs integrated electrode exhibits a high initial capacity of 882.7 mAh · g ^−1 and excellent cyclic stability of 832.1 mAh · g ^−1 after 100 cycles at 1.0 A · g ^−1 which is much better than traditional coated electrode of CoFe _2 O _4 nanowire (defined as CFO NWAs) and CoFe _2 O _4 nanowire/Cu foil integrated electrode (named CFO/Cu-foil NWAs). The improved electrochemical performance might be attributed to superior conductivity and porous skeleton structure which not only reduce contact resistance and polarization, but also relieve volume alteration during the lithiation/delithiation process. These advantages make the CoFe _2 O _4 /Cu foam integrated electrode a promising anode for Li-ion batteries.

The LiNi0.5Mn1.5O4 ||Li4Ti5O12 (LMNO||LTO) battery possesses a relatively-high energy density and cycle performance, with further enhancement possible by application of an AlF3 coating on the LTO electrode particles. We measure the performance enhancement to the LMNO||LTO battery achieved by a AlF3 coating on the LTO particles through electrochemical testing and use in-operando neutron powder diffraction to study the changes to the evolution of the bulk crystal structure during battery cycling. We find that the AlF3 coating along with parasitic Al doping slightly increases capacity and greatly increases rate capability of the LTO electrode, as well as significantly reducing capacity loss on cycling, facilitating a gradual increase in capacity during the first 50 cycles. Neutron powder diffraction reveals a structural response of the LTO and LNMO electrodes consistent with a greater availability of lithium in the battery containing AlF3-coated LTO. Further, the coating increases the rate of structural response of the LNMO electrode during charge, suggesting faster delithiation, and enhanced Li diffusion. This work demonstrates the importance of studying such battery performance effects within full configuration batteries.

Abstract A carbon nanotube sheet having homogeneously distributed BaTiO 3 is applied to the Li-S cell system as a pseudo-current collector between the cathode and separator. This interlayer serves as a site distributor, where polysulfide eluted from the cathode continuously reacts, and it is expected to play a role as a more effective current collector by mixing the ferroelectric material. A cell utilizing a ferroelectricity embedded interlayer exhibits a higher capacity (908 mAh g−1) at 0.2C than that of carbon alone (740 mAh g−1) at 200th cycle. This result corresponds to a capacity retention ratio enhancement from 67.5% to 75.6%. Furthermore, it is confirmed that the retention of the coulombic efficiency is effectively maintained in long cycles at 0.5C (94.5%–99.6%). This is not only because the modified interlayer functions as an effective current collector owing to the high affinity of the ferroelectric material to polysulfide, but also because ferroelectricity in the interlayer acts as a polysulfide anchor. The evenly distributed polarization leads to a uniform deposition of sulfur, which results in the prevention of inactive sulfur agglomeration and dissolution of polysulfide. Thus, the utilization of active material can be improved with stabilized reaction. Graphical abstract Image 1 Highlights • Nano-BaTiO 3 embedded MWCNT interlayer is fabricated by vacuum filtration method. • BaTiO 3 interlayer cell performs higher specific capacity and coulombic efficiency. • BaTiO 3 interlayer cell enhances rate capability. • BaTiO 3 interlayer induces homogeneous S distribution with strong affinity. • BaTiO 3 interlayer acts as an efficient pseudo-current collector. [ABSTRACT FROM AUTHOR]

Abstract Fe 3 O 4 @C composite was designed and synthesized by a facile one-step solvothermal route as an anode material for Li-ion batteries (LIBs). The carbon shell can effectively prevent the aggregation and buffer the volume expansion during charge/discharge process. The electrochemical performance displays that the Fe 3 O 4 @C composite exhibits high reversible capacity and good cycling performance. In particular, it displays excellent cycling stability at 2 C rate (640.5/642.2 mA h g−1 after 1000 cycles). The results indicate a simple and useful route to prepare Fe 3 O 4 @C composite as a promising LIBs anode material. Graphical abstract Fe 3 O 4 @C composite with high reversible capacity and good cycling performance has been synthesized by a facile one-step solvothermal route as an anode material for Li-ion batteries (LIBs). fx1 Highlights • Fe 3 O 4 @C composite has been synthesized by a facile one-step solvothermal route. • Fe 3 O 4 @C composite has been studied as an anode material for LIBs. • Fe 3 O 4 @C composite displays high reversible capacity and good cycling performance. [ABSTRACT FROM AUTHOR]

We investigated the applicability of an ionic liquid electrolyte to a phosphorus‐doped Si (P‐doped Si) electrode to improve the performance and safety of the lithium‐ion battery. The electrode exhibited excellent cycling performance with a discharge capacity of 1000 mA h g−1 over 1400 cycles in the ionic liquid electrolyte, whereas the capacity decayed at the 170th cycle in the organic electrolyte. The lithiation/delithiation reaction of P‐doped Si occurred a localized region in the organic electrolyte, which generated a high stress and large strain. The strain accumulated under repeated charge‐discharge cycling, leading to severe electrode disintegration. In contrast, the reaction of P‐doped Si proceeded uniformly in the ionic liquid electrolyte, which suppressed the electrode disintegration. The P‐doped Si electrode also showed good rate performance in the ionic liquid electrolyte; a discharge capacity of 1000 mA h g−1 was retained at 10 C. A P‐doped Si electrode exhibited excellent cycling performance with a discharge capacity of 1000 mA h g−1 over 1400 cycles in an ionic liquid electrolyte, whereas the capacity decayed at approximately the 170th cycle in an organic electrolyte. It is concluded that the ionic liquid electrolytes could be successfully applied to a P‐doped Si electrode and that they represent one type of promising electrolyte for next‐generation LIBs with this electrode. [ABSTRACT FROM AUTHOR]

Abstract This work explores the compound Li 1+z/3 Ni 1/2-z/2 Ti 1/2+z/6 O 2 (z = 0, 0.1, 0.2, 0.3, 0.4, 0.5) and compares the electrochemical performance difference with z to the proposed percolation network. X-ray diffraction combined with Rietveld refinements show that rock-salt structure is obtained by the simple sol-gel process, and the lattice parameters are increased with the increasing level of Li-excess. Micromorphology observation reveals that particles are irregular and the size is distributed within 100 nm. In addition, a detailed reaction mechanism is examined by X-ray photoelectron spectroscopy and cyclic voltammetry, which exhibits the evolution of Ni, Ti and O in the initial charge-discharge process and confirms that they all make contributions to capacities. Electrochemical performance test shows that the discharge capacities increase with the amount of Li and Li 1.17 Ni 0.25 Ti 0.58 O 2 delivers the discharge capacities up to 223.9 mAh g−1. At the current density of 400 mA g−1, it still provides a large capacity of 120 mAh g−1. Furthermore, Li 1.17 Ni 0.25 Ti 0.58 O 2 has the highest lithium ion diffusion coefficient among all samples. Graphical abstract Image 1 Highlights • The good crystallized Li 1+z/3 Ni 1/2-z/2 Ti 1/2+z/6 O 2 is prepared by a facile method. • The detailed redox process of Ni, Ti and O during the first cycle. • Stable structure and 0-TM network improve performance. • Li 1.17 Ni 0.25 Ti 0.58 O 2 exhibits high capacities and good rate capability. [ABSTRACT FROM AUTHOR]

Highlights • A new hexagonal prisms CoO was assembled on reduced graphene oxide. • CoO in the composite is pure purity. • The composite performed high capacity as anode materials of lithium ion batteries. Abstract In this research, we use a modified sol-gel method to obtain a pure phase new hexagonal CoO on reduced graphene oxide by leading of polar solvent. In the electrochemical test, the CoO/rGO composite shows a remarkable performance of capacity as an anode of a lithium ion battery. The electrochemistry performance shows that the capacity of the composite can remain at 1300 mAh/g in 100 cycles without damping. The pure phase of CoO and its hexagonal morphology have been characterized by XRD, SEM and TEM. [ABSTRACT FROM AUTHOR]

The structural and electrochemical effects of electrospun V2O5 with selected redox-inactive dopants (namely Na+, Ba2+ and Al3+) have been studied. The electrospun materials have been characterised via a range of analytical methods including X-ray diffraction, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area measurements and scanning and transmission electron microscopy. The incorporation of dopants in V2O5 was further studied with computational modelling. Structural analysis suggested that the dopants had been incorporated into the V2O5 structure with changes in crystal orientation and particle size, and variations in the V4+ concentration. Electrochemical investigations using potentiodynamic, galvanostatic and impedance spectroscopy analysis showed that electrochemical performance might be dependent on V4+ concentration, which influenced electronic conductivity. Na+- or Ba2+-doped V2O5 offered improved conductivities and lithium ion diffusion properties, whilst Al3+ doping was shown to be detrimental to these properties. The energetics of dopant incorporation, calculated using atomistic simulations, indicated that Na+ and Ba2+ occupy interstitial positions in the interlayer space, whilst Al3+ is incorporated in V sites and replaces a vanadyl-like (VO)3+ group. Overall, the mode of incorporation of the dopants affects the concentration of oxygen vacancies and V4+ ions in the compounds, and in turn their electrochemical performance.ᅟ [ABSTRACT FROM AUTHOR]

Abstract Poly(vinylidene fluoride- co -hexafluoropropylene) (P(VDF-HFP))-based composite polymer electrolytes (CPEs) doped with different amounts of CaTiO 3 inorganic fillers are prepared by phase inversion. With adding the CaTiO 3 fillers into the P(VDF-HFP) polymer matrix, the CPE membranes show more abundant and uniform micro-pore structure with lower crystallinity, better thermal stability and mechanical strength. The characterization results show that the ionic conductivity at room temperature and electrochemical working window of the CPE doped with 5 wt% CaTiO 3 fillers (CPE-5) can be up to about 3.557 mS cm−1 and 5.1 V, respectively. The interfacial resistance of the Li/CPE-5/Li simulated cell can quickly stabilize at 750 Ω after 5 days storage, and the assembled LiCoO 2 /CPE-5/Li coin cell shows excellent rate and cycle performance. Moreover, the CPE-5 membrane can still well maintain the original micro-pore structure after 100 cycles at 1.0 C without visible cracks. Those results suggest that the as-fabricated CPE doped with 5 wt% CaTiO 3 inorganic fillers may become a promising polymer electrolyte for the lithium ion battery Graphical abstract Cycling performance and coulombic efficiency plots of the LiCoO 2 /CPE-5/Li battery after 100 cycles at 1.0 C (The insert are the SEM images and digital photographs of the CPE-5 before and after cycle). Unlabelled Image Highlights • P(VDF-HFP)-based CPE membranes doped with different amounts of CaTiO 3 ceramics are fabricated by phase inversion. • The electrolyte uptake and ionic conductivity of the CPE-5 can be up to 187.4% and 3.557 mS cm−1. • The Li/CPE-5/Li simulated cell possesses good interfacial stability. • The assembled LiCoO 2 /CPE-5/Li battery shows good rate and cycle performance. [ABSTRACT FROM AUTHOR]

Abstract This work is focused on applying structural concepts and basic chemical principles to model two N -heterocyclic lithium salts, based on trifluoromethyl substituted pyrazolide anions. An easily upscalable preparation method without difficult purification steps was also developed. In a comparative study, the physicochemical properties of the two new lithium salts were investigated, particularly the effect of an additional BF 3 -group at the nitrogen atom. In comparison to non-substituted lithium pyrazolide, the BF 3 -addition led to a strong improvement of thermal and electrochemical stability, ionic conductivity, as well as better C-rate and cycling performance. Furthermore, the anodic stability of Al current collectors was investigated and compared to commercial lithium salts, namely LiPF 6 and lithium bis((trifluoromethyl)sulfonyl)imide (LiTFSI). Possible mechanisms that lead to the presented improvements are discussed. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Abstract: A new strategy is proposed to synthesize a Si−Ge alloy nanomaterial for a Li‐ion battery anode. Magnesiothermic reduction of the SiO2−GeO2 composite parent material could provide a nanostructured Si−Ge alloy material with unique canyon‐like surface porosity. The nanostructure of Si−Ge alloys could be intentionally controlled and the resulting canyon‐like porous Si−Ge nanoparticle could be successfully utilized as an anode material, achieving satisfactory cell performance. The proposed synthetic approach can potentially scale‐up the production of Si−Ge alloy nanomaterial. [ABSTRACT FROM AUTHOR]

A low-cost and scalable ultrasonic synthetic method to produce copper metal current collector with uniform nanopores on the surface is achieved for the first time. A layer of silicon active material was sputtered on the surface of as-prepared metal current collector (vs. metal lithium) as an innovative current collecting material for lithium ion battery. The assembled battery with this current collector showed an areal capacity of 2.2 mAh/cm 2 , comparable to that of commercially available lithium ion batteries. Due to the nano-porous structure of current collector, the silicon active material electrochemical capacity retention and cycling stability also improved significantly. [ABSTRACT FROM AUTHOR]

Layered Ni-rich Li[Ni 0.6 Mn 0.2 Co 0.2- x Sn x ]O 2 cathode active materials with x  = 0–0.05 are synthesized via a co-precipitation synthesis route and the effect of doping content on the structural behavior and electrochemical performance are investigated. All synthesized materials show a well-defined layered structure of the hexagonal α -NaFeO 2 phase (space group R 3 ¯ m ) analyzed by X-ray diffraction (XRD). Electrochemical Li-metal/cathode cell studies exhibit that a Sn-content of 1%–2% is beneficial regarding specific discharge capacity and cycle life (≥20%). Detailed electrochemical investigations of Li-metal and lithium ion cells with cathodes consisting of LiNi 0.6 Mn 0.2 Co 0.2 O 2 and LiNi 0.6 Mn 0.2 Co 0.18 Sn 0.02 O 2 are conducted. Post mortem analyses by means of ICP-OES and TXRF show beneficial effects of the Sn-doping with regard to a lower transition metal dissolution and a higher available Li content in the cathode active material. The thermal analyses (TGA, DSC, ARC) show a stabilizing effect of Sn-doping, which results from a lower mass loss and less heat evolution of the charged cathode active materials at elevated temperatures. [ABSTRACT FROM AUTHOR]

The homogeneous nano-CeO 2 coated on the LiNi 1/3 Co 1/3 Mn 1/3 O 2 powder like substrate was prepared via a novel hydrolytic precipitation reaction followed by the thoroughly baking at 450 °C. The chemical composite of nano-CeO 2 coating layer was spectroscopically examined by X-ray diffraction, field-emission scanning electron microscopy and X-ray photoelectron spectrometer. The electrochemical characterization of the resulting materials proclaim that nano-CeO 2 coating can drastically improve lithium storage performances. The optimum coating amount of CeO 2 is as high as 2 wt%, which rendered a discharge capacity of 148.9 mAh g −1 with 91.6% capacity retention ensuing as many as 100 cycles. In particular, the exothermic peak is vastly increased from 256.4 to 338.2 °C. The value is superior to its counterparts, LiNi 1/3 Co 1/3 Mn 1/3 O 2 . It paves a new avenue for developing high safety lithium batteries. [ABSTRACT FROM AUTHOR]

Abstract: To improve the electrochemical performance of pure poly[(vinylidene fluoride)‐co‐hexafluoropropylene] (P(VDF‐HFP))‐based gel polymer electrolytes, different amounts of monodispersed ZrO2 nanoparticles were introduced to fabricate P(VDF‐HFP)/ZrO2 composite polymer electrolytes (CPEs) using the phase inversion method and activated processes, in which the monodispersed ZrO2 nanoparticles were synthesized by an easy route without any chelating agents or surfactants, and confirmed using scanning electron microscopy, particle size distribution measurement and X‐ray diffraction. The characterization results show that the as‐fabricated CPE membranes present not only an abundant porous structure, but also an improved mechanical strength. In particular, sample CPE‐5 presents the best properties when the doped content of the monodispersed ZrO2 nanoparticles reaches 5 wt% in the polymer matrix, in which the liquid uptake and ionic conductivity at room temperature are about 192.4% and 3.926 mS cm−1, and the electrochemical working window and thermal decomposition temperature can increase to 5.1 V and 420 °C, respectively. Moreover, an assembled LiCoO2/CPE‐5/Li coin cell can deliver excellent rate and cycling performance, in which the discharge specific capacity of the cell can show about 83.95% capacity retention at 2.0 C after 85 cycles. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The Li 2 SiO 3 -graphene composite is successfully synthesized through an easy hydrothermal method. The structures and morphologies of the produced samples are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectrum, Brunauer-Emmett-Teller formalism, scanning electron microscope, transmission electron microscope, and electrochemistry methods. The result shows a well crystalline of the Li 2 SiO 3 -GE composite. The existence of graphene doesn’t change the crystalline of Li 2 SiO 3 . In addition, the Li 2 SiO 3 compound with an average diameter of 20 nm can be seen on the surface of graphene with uniform distribution. After the composite with graphene, the composite displays large surface area which ensures the well electrochemistry of the composite. Finally, the Li 2 SiO 3 -graphene composite delivers a high initial capacity of 878.3 mAh g −1 at 1C as well as a high recovery capacity of 400 mAh g −1 after 200 cycles. When charged and discharged at high rate, the Li 2 SiO 3 -doping graphene composite still exhibits a high specific capacity of 748.3 mAh g −1 (at 2C, and 576 mAh g −1 at 5C) and well cycling performance. The well synthesized composite possesses well structure and well electrochemistry performance. [ABSTRACT FROM AUTHOR]

A liquid-phase mixing method is adopted to uniformly disperse the graphene nanosheets onto LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathode for high-performance Li-ion batteries (LIBs). The electrochemical performance was characterized using a full pouch cells with state-of-the-art electrode areal loading (compared to half coin cells). The addition of graphene sheets (i.e., only 1 wt%) significantly improves the high rate capability for charging and discharging operation. For example, 6 times improvement in 5  C charging was achieved providing further insights in enabling extreme fast charging for LIBs. Other benefits include longer cycleability, lower internal resistance, and higher lithium ion diffusion coefficient, demonstrated by charge-discharge cycling tests and electrochemical impedance spectroscopy. Higher capacity retention of 88.2% and decreased internal resistance of ∼0.9 Ω are observed after 400 cycles. The diffusion coefficient of Li ions is 6.49 × 10 −8  cm 2  s −1 when charged to 4.2 V, which is approximately 1.37 times higher compared to the configuration with no graphene sheet (4.74 × 10 −8  cm 2  s −1 ). The improved performance is ascribed to a robust network among the active materials formed by graphene sheets, which serves as an extended current conductor and facilitates charge transfer, ionic reversibility, and ionic transportation. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) layers have been grown by spray-pyrolysis technique by using different spray pyrolysis deposition times (t sp ). AgNPs with ca. 80 nm mean diameter have been obtained for the lower t sp value, whereas as the spray-pyrolysis time value is increased, the Ag NPs diameters increased, reaching a AgNPs mean diameter of 190 nm for the highest t sp assayed value. X-ray diffraction patterns of the AgNPs layers samples exhibited a pure polycrystalline cubic silver phase, irrespective of the different t sp values. An optical visible light transmittance maximum of 60% at 550 nm has been observed for samples grown at t sp  = 5 s and 10 s. For higher t sp values this optical transmittance decreases. A semitransparent lithium ion battery (t sp  = 5 s) has been obtained, exhibiting an optical transmittance of about 49% at λ = 554 nm. Electrochemical measurements showed that the amount of lithium that reacted with the AgNPs layer was around 6 lithium/mol. By cycling a transparent Li/Ag-ITO single cell, good capacity retention was observed for the first ten cycles for which a high value of capacity is delivered: 706 A h kg −1 .When assembling this electrode in a full semitransparent battery, the electrochemical processes resulted to be reversible and the transparency preserved. [ABSTRACT FROM AUTHOR]

Lithium ion battery (LIB) waste contains significant valuable resources that could be recovered and reused to manufacture new products. This study aimed to develop an alternative process for extracting metals from LIB waste using acidic solutions generated by electrolysis for leaching. Results showed that solutions generated by electrolysis of 0.5 M NaCl at 8 V with graphite or mixed metal oxide (MMO) electrodes were weakly acidic and leach yields obtained under single stage (batch) leaching were poor (<10%). This was due to the highly acid-consuming nature of the battery waste. Multistage leaching with the graphite electrolyte solution improved leach yields overall, but the electrodes corroded over time. Though yields obtained with both electrolyte leach solutions were low when compared to the 4 M HCl control, there still remains potential to optimise the conditions for the generation of the acidic anolyte solution and the solubilisation of valuable metals from the LIB waste. A preliminary value proposition indicated that the process has the potential to be economically feasible if leach yields can be improved, especially based on the value of recoverable cobalt and lithium. [ABSTRACT FROM AUTHOR]

In this work, we select four types of substitute cations, Ti 4+ , Al 3+ , Mg 2+ and Zn 2+ , to compare their influence on LiNi 0.8 Co 0.1 Mn 0.1 O 2 . After modification, the average lengths of Ni O bonds are elongated with the turn of the Ti , Al , Mg , pristine and Zn-substituted, namely the bond energies are diminished with this sequence, according to their roughly inverse square relation. This tendency is also obeyed by oxygen defects, which induces the Ni Li exchanging and surface decomposition, and then exert the effect on electrochemical behavior of Ni-rich cathodes. Among the investigated samples, the Ti-modified sample, which possesses the highest Ni O bond energy, presents the best cyclic stability and rate capability, retaining 93.8% in the 200 th cycle and 155.1 mAh g −1 under 5C, which is ∼12% higher than the pristine sample. Our approaches illustrate the importance of Ni O network and provide a novel thought to further improve these promising cathodes. [ABSTRACT FROM AUTHOR]

A new three-dimensional (3D) sandwich-like Si/Polyaniline/Graphene nanoarchitecture anode for lithium ion batteries (LIBs) is successfully fabricated through an easy approach. In this nanoarchitecture, the in-situ polymerized electronic conductive polyaniline (PAni) hydrogel, acting as “glue”, agglutinates tightly to both the silicon nanoparticles (SiNPs) and graphene sheets, forming efficient conductive networks with high elastic modulus and high tensile strength. This mechanically robust nanoarchitecture can endure the great volume change of silicon and retain structural stability during Li-ion insertion/extraction. The electrodes consisting of this 3D sandwich-like Si/Polyaniline/Graphene nanoarchitecture reveal excellent electrochemical performance. The progress made in this work provides an easy and scalable route for preparing Si-based anode materials with high performance for advanced LIBs. [ABSTRACT FROM AUTHOR]

The electrochemical performances of LiMnNiCoO cathode material are enhanced through hydrothermal approach using NaS solution as a medium. Furthermore, the influence of contents of NaS solution on the morphology, structure, and electrochemical performances is fully investigated. The results indicate that a high content of NaS solution results in the formation of spinel particles which are detected by SEM, XRD, and HR-TEM measurements. The formation of spinel particles leads to a deterioration of electrochemical performances. However, a low content of NaS solution results in a slight structure change from layered phase to spinel one near the edge of LiMnNiCoO particles. This slight structure change facilitates the decrease of charge transfer resistance, which contributes to the enhanced rate capability of NaS-treated LiMnNiCoO. [ABSTRACT FROM AUTHOR]

The charge/discharge mechanism and electrochemical performance of Zn 3 V 3 O 8 as anode for Li-ion batteries are systematically studied. Theoretical calculation predicts that Zn 3 V 3 O 8 can act as a host for Li storage, and a possible diffusion way of Li-ions within the crystal structure is calculated via first principle methods. Experimentally, Zn 3 V 3 O 8 nanosheets with porous architecture are fabricated via a facile hydrothermal pretreatment and subsequent sintering. The Zn 3 V 3 O 8 shows superior electrochemical performance with graphite electric additive, exhibiting discharge/charge capacity of 541/537 mAh g −1 after 200 cycles at a specific current of 120 mA g −1 . The Li-storage mechanism is also studied via ex-situ XRD, and the maintenance of main diffraction peaks during lithiation/delithiation process suggests a possible intercalation/extraction mechanism of the Zn 3 V 3 O 8 . [ABSTRACT FROM AUTHOR]

Silicon (Si) is promising for high capacity anodes in lithium‐ion batteries due to its high theoretical capacity, low working potential, and natural abundance. However, there are two main drawbacks that impede its further practical applications. One is the huge volume expansion generating during lithiation and delithiation progresses, which leads to severe structural pulverization and subsequently rapid capacity fading of the electrode. The other is the relatively low intrinsic electronic conductivity, therefore, seriously impacting the rate performance. In the past decades, numerous efforts have been devoted for improving the cycling stability and rate capability by rational designs of different nanostructures of Si materials and incorporations with some conductive agents. In this review, the authors summarize the exciting recent research works and focus on not only the synthesis techniques, but also the composition strategies of silicon nanostructures. The advantages and disadvantages of the nanostructures as well as the perspective of this research field are also discussed. We aim to give some reference for engineering application on Si anodes in lithium ion batteries. [ABSTRACT FROM AUTHOR]

Nowadays, exploiting electrode materials with high energy density and long cycling life is crucial for meeting the urgent requirement of ever-growing energy storage for EV/HEV. Herein, we introduced a simple synthetic route to prepare FeNi 2 S 4 QDs @C composites on a large scale. By means of suitable design, the ultra-small FeNi 2 S 4 quantum dots (QDs) were encapsulated in the carbon matrix, and the forming FeNi 2 S 4 QDs @C composites exhibit excellent electrochemical performances. When tested as anode materials for lithium ion battery, the high capacity of 920 mAhg −1 at 0.1 Ag -1 could be achieved. Except the high capacity, the FeNi 2 S 4 QDs @C composites present the enhancing cycling stability, which demonstrated more than 700 cycles with twice capacity of graphite and capacity retention of almost 100% could be achieved, compared to the capacity of second cycle. Detailed investigations of phase evolutions by XRD patterns and TEM indicate the phase segregation of FeS x and NiS y during the charge/discharge process. The conversion reactions between Fe/Ni and FeS x /NiS y took place in the carbon matrixes, which would hinder the aggregation and grow-up of nanoparticles, resulting in the structure stability. Hence, the ultra-small size, self-doping and stable structure led to the superior electrochemical properties. We believe that the FeNi 2 S 4 @C composites would be an alternative anode material for next generation lithium ion battery. [ABSTRACT FROM AUTHOR]

Li-rich layered cathode materials have been considered the most promising candidates for large-scale Li-ion batteries due to their low cost and high reversible capacity. However, these materials have many drawbacks that hinder commercialization, such as low initial efficiency and cyclability at elevated temperatures. To overcome these barriers, we propose an efficient and effective surface modification method, in which chemical activation (acid treatment) and LiCoPO coating were carried out simultaneously. During the synthesis, the lithium ions were extracted from the lattice, leading to improved Columbic efficiency, and these ions were used for the formation of LiCoPO. The Ni and Co doped spinel phase was formed at the surface of the host material, which gives rise to the facile pathway for lithium ions. The LiCoPO and highly doped spinel on the surface acted as double protection layers that effectively prevented side reactions on the surface at 60 °C. Moreover, the transition metal migration of the modified cathode was weakened, due to the presence of the spinel structure at the surface. Consequently, the newly developed Li-rich cathode material exhibited a high 1st efficiency of 94%, improved capacity retention of 82% during 100 cycles at 60 °C, and superior rate capability of 62% at 12C (1C = 200 mA/g) rate at 24 °C. In addition, the thermal stability of the modified cathode was significantly improved as compared to that of a bare counterpart at 4.6 V, showing a 60% decrease in the total heat generation. [ABSTRACT FROM AUTHOR]

Cathode materials LiMn 0.5 Fe 0.5 PO 4 /C and LiMnPO 4 /C were synthesized by a high-energy ball-milling assisted sol-gel method. The LiMn 0.5 Fe 0.5 PO 4 consists of nanorods and nanoparticles homogeneously wrapped with highly ordering carbon. The increased Néel-temperature and decreased effective magnetic moment of LiMn 0.5 Fe 0.5 PO 4 /C revealed the microstructure differences from LiMnPO 4 /C. Meanwhile, tiny amount of ferromagnetic impurities is detected in LiMn 0.5 Fe 0.5 PO 4 /C by magnetic tests. The synergetic effects of Fe substitution and carbon coating remarkably improve rate capacity and cyclic stability of LiMn 0.5 Fe 0.5 PO 4 /C. This solid solution delivers initial discharge capacities of 128.6 mAh g −1 and 116.3 mAh g −1 and capacity retentions of 93.5% and 90.3% after 100 cycles at 1C and 2C respectively, significantly better than LiMnPO 4 /C. [ABSTRACT FROM AUTHOR]

Chromium nitride (CrN) synthesized by heating at 550 °C under a continuous stream of ammonia has been investigated as anode material for lithium electrochemistry. Due to its low lithium insertion potential, Cr is an attractive material for lithium–ion battery application, but the usual volume variation effect obstructs its practical use. In this study, different concentrations of carbon nanotubes doped with nitrogen (NCNTs) are combined with CrN to attain high electrochemical performance. The synthesized CrN/0.08%–NCNTs nanocomposite demonstrates network structure with 30–40 nm CrN nanoparticles anchored to specific sites on 40–60 nm diameter NCNTs. Upon electrochemical testing, CrN/0.08%–NCNTs nanocomposite displays a discharge capacity of 1172 mAh g −1 after 200 cycles with high coulombic efficiency (∼100%) and rate capability. The electrode can deliver a reversible capacity of 1042.9 mAh g −1 at 20 C. The n-type concentration, along with the conductive CNTs framework, mesoporous channels, appropriate surface area and buffering capability of CNTs, are together responsible for the excellent electrochemical performance. The electrochemical reaction mechanism of CrN with lithium is explored by investigating the structural changes using ex situ X-ray photoelectron spectroscopy, X-ray diffraction, selected area electron diffraction, and high-resolution transmission electron microscopy. The reversible conversion reaction of CrN into Cr metal and Li 3 N is revealed. [ABSTRACT FROM AUTHOR]