•The mechanisms and characteristics of ALD technique have been concluded.•ALD refining the reaction interfaces and cell configurations have been reviewed.•The key applications where ALD can make the largest impact have been summarized.•The opportunities and perspective of ALD in Li-S system have been discussed.With the significant obstacles that have been conquered in lithium-sulfur (Li-S) batteries, it is urgent to impel accelerating development of room-temperature Li-S batteries with high energy density and long-term stability. In view of the unique solid-liquid-solid conversion processes of Li-S batteries, however, designing effective strategies to address the insulativity and volume effect of cathode, shuttle of soluble polysulfides, and/or safety hazard of Li metal anode has been challenging. An atomic layer deposition (ALD) is a representative thin film technology with exceptional capabilities in developing atomic-precisely conformal films. It has been demonstrated to be a promise strategy of solving emerging issues in advanced electrical energy storage (EES) devices via the surface modification and/or the fabrication of complex nanostructured materials. In this review, the recent developments and significances on how ALD improves the performance of Li-S batteries were discussed in detail. Significant attention mainly focused on the various strategies with the use of ALD to refine the electrochemical interfaces and cell configurations. Furthermore, the novel opportunities and perspective associated with ALD for future research directions were summarized. This review may boost the development and application of advanced Li-S batteries using ALD.The controllable modification of any LIB component with ALD technique can significantly improve the Li-S cell performance without impacting the energy density, which opens a new opportunity for developing high-energy Li-S batteries with long-term stability.Download high-res image (254KB)Download full-size image

To uniformly encapsulate electrode materials with reduced graphene oxide (rGO) has been a considerable challenge due to the lack of appropriate synthetic methods and/or effective reaction systems. In this study, we present a one-step rapid and scalable solvothermal approach to achieve a crumpled reduced graphene oxide encapsulated VO2 material. As a demonstration of this promising configuration, for the first time, we systematically studied its Na+ storage behavior in the voltage range of 3.0 to 0.01 V (versus Na/Na+). It turned out that the as-prepared anode material exhibits high reversible capacities of 383 mA h g−1 at 0.1 A g−1 and 214 mA h g−1 at 4 A g−1, and can stably operate for as long as 2000 cycles at 4 A g−1 with a capacity fade of 0.013% per cycle, resulting from the improved electronic conductivity, structural stability, and electrode wettability. Furthermore, the formation mechanism and structural features of the desired crumpled reduced graphene oxide encapsulated VO2 material are discreetly expounded. More interestingly, a chain of cogent evidence is provided by coating on various electrode materials to confirm the scalability of this facile and rapid solvothermal synthesis method, which would open up a novel avenue to create more fascinating graphene-based functional materials for the multitudinous application domain.

•Mineralogy of antigorite was studied and its powder was characterized.•Antigorite powders can reduce friction coefficient, wear and power consumption of the driving motor.•The friction-reduction mechanisms of antigorite powders were discussed.Reduction of friction and wear by lamellar solid powders in lubricating system is a valid approach that can allow to formulate energy saving lubricants. An experimental study has been made of the friction properties of antigorite powders having flaked-bladed morphology and 0.86 µm of the mean particle size. The results showed that antigorite transformed to forsterite (at 793 °C) and enstatite+forsterite (at 831 °C). The friction coefficient, the wear volume and power consumption of the driving motor in system with antigorite powders were respectively reduced by 19.3%, 33.33% and 4.5–5.0% as compared with base oils. Results are explained using particle spacing-polishing and friction-induced formation of like-ceramic film mechanism.

•Ni3S2/Ni nanostructures with different morphologies have been successfully designed.•The clustered network-like electrode shows high performance for sodium ion batteries.•The special performance evolutions of these electrodes were systematically studied.•The influence of morphology on performance evolution was discussed in detail.Transition metal sulfides have been treated as promising materials for lithium-ion battery, and recently more and more attention has been paid to its applications in sodium-ion batteries. In our context, three Ni3S2 nanostructures directly grown on Ni foam were successfully designed using a facile hydrothermal method. The influences of the morphology on the performance evolution for sodium-ion batteries were studied in detail. As a result, it was found that the initial drop, gradual increase, convex type decline and concave type decline in the performance evolutions were mainly controlled by Rct, Rsf, pulverization, and internal stress, respectively. More importantly, our results indicated that the clustered network-like structure was beneficial for the cycling and rate performance, while the rod-like structure was suitable for the cyclic stability of these electrodes.Three Ni3S2/Ni nanostructures with different morphologies are successfully designed at selected reaction temperatures. Their electrochemical performances are compared and their special down and up performance evolutions are discussed systematically for the first time. Most importantly, the effect of morphology on the performance evolution is studied in detail. It is demonstrated that using materials with different morphologies have a bright prospect to improve the performance of these electrodes for sodium ion batteries.

•Crumpled reduced graphene oxide encapsulated V2O5 have been successfully fabricated.•The formation mechanism of the desired materials was systematically studied.•The resultant electrode delivers brilliant cycling stability, rate capacity, and energy density.•The proposed reaction system can be extended to encapsulate other materials.It has remained a challenge to develop a facile and scalable approach to synthesize high-energy lithium-ion battery (LIB) electrode materials with excellent rate capabilities and prominent cycling stabilities for their applications in new generation energy storage devices. In this study, for the first time, we report a crumpled reduced graphene oxide (cG) encapsulated three-dimensional (3D) hollow vanadium pentoxide (V2O5) nano/microspheres fabricated by one-step solvothermal treatment followed by subsequent annealing. This rapid and effective synthesis method is environmental friendly and economically beneficial without involving costly organic vanadium sources, tedious operation, or sophisticated equipment. Remarkably, the desired cG-encapsulated V2O5 composite contains 5 wt% reduced graphene oxide (rGO), yet exhibits outstanding rate capacities and cycling stabilities. This product can deliver reversible capacities of 289 mA h g−1 at 100 mA g−1 and 163 mA h g−1 at 5000 mA g−1 (492 W h kg−1 and 9840 W kg−1), as well as a capacity retention of about 94% after 200 cycles at 2000 mA g−1 in the potential range between 2.0 V and 4.0 V (vs. Li/Li+). Furthermore, the unique structural feature and typical formation mechanism of the designed materials are clarified based on multiple experimental results. More commendably, a chain of solid powders had been successfully encapsulated using this scalable reaction system. It is expected that this versatile approach will facilitate the applications of cG, and provide a novel avenue to create more fascinating rGO-based functional materials.The crumpled reduced graphene oxide encapsulated hollow V2O5 nano/microspheres were fabricated by one-step solvothermal treatment followed by subsequent annealing for the first time. The unique structural feature and typical formation mechanism of the designed materials were clarified based on multiple experimental results. The resulting electrode presented brilliant rate capacity, excellent cycling stability, and outstanding energy density. Most importantly, we have demonstrated that the proposed reaction system can be extended to encapsulate other materials.

Spinel Li4Ti5O12 performance highly depends on both the electronic and ionic conductivity, however, developing a low-cost strategy to improve its electronic and ionic conductivity still remains challenging. In this study, a facile cost-saving carbothermal reduction method is introduced to synthesize the microscaled spinel Li4Ti5O12 particles with the surface modification of Ti(III) using anatase–TiO2, Li2CO3, and acetylene black (AB) as precursors. Remarkably, this ingenious design can easily eliminate the influence of the residual carbon, and thus makes it possible to individually study the effect of the Ti(III) on the bulk Li4Ti5O12. To reveal the role of the Ti(III), the electronic conductivity and lithium-ion diffusion coefficient of the as-prepared materials were measured using a direct volt-ampere method, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The results indicate that the carbothermal reduction leads to the increased electronic and ionic conductivity of the spinel Li4Ti5O12. As a result, the modified Li4Ti5O12 exhibits an enhanced cyclic stability, improved rate capability, and high Coulombic efficiency. The carbothermal reduction mechanism discreetly clarified in this study is beneficial to improving Li4Ti5O12 performance for further commercial applications.

•The electrochemical reaction kinetics of the Ni/NiO anode was studied for the first time.•Charge transfer resistance is main contribution to total resistance during discharge process.•The slow growth of the SEI film is responsible for the capacity fading upon cycling.•Some promising strategies to optimize NiO anode performance were summarized.The electrochemical reaction kinetics of the porous core–shell structured Ni/NiO anode for Li ion battery application is systematically investigated by monitoring the electrochemical impedance evolution for the first time. The electrochemical impedance under prescribed condition is measured by using impedance spectroscopy in equilibrium conditions at various depths of discharge (DOD) during charge–discharge cycles. The Nyquist plots of the binder-free porous Ni/NiO electrode are interpreted with a selective equivalent circuit composed of solution resistance, solid electrolyte interphase (SEI) film, charge transfer and solid state diffusion. The impedance analysis shows that the change of charge transfer resistance is the main contribution to the total resistance change during discharge, and the surface configuration of the obtained electrode may experience significant change during the first two cycles. Meanwhile, the increase of internal resistance reduced the utilization efficiency of the active material may be another convincing factor to increase the irreversible capacity. In addition, the impedance evolution of the as-prepared electrode during charge–discharge cycles reveals that the slow growth of the SEI film is responsible for the capacity fading after long term cycling. As a result, several strategies are summarized to optimize the electrochemical performances of transition metal oxide anodes for lithium ion batteries.

•Hierarchical porous vanadium pentoxide nanofibers were synthesized by electrospinning.•V2O5 nanofibers showed much enhanced lithium storage performance.•Kinetics process of electrospinning V2O5 nanofibers was studied by means of EIS for the first time.•Strategies to enhance the electrochemical performance of V2O5 electrode were concluded.The hierarchical V2O5 nanofibers cathode materials with diameter of 200–400 nm are successfully synthesized via an electrospinning followed by annealing. Powder X-ray diffraction (XRD) pattern confirms the formation of phase-pure product. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) obviously display the hierarchical porous nanofibers constructed by attached tiny vanadium oxide nanoplates. Electrochemical behavior of the as-prepared product is systematically studied using galvanostatic charge/discharge testing, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). It turns out that in comparison to the commercial V2O5 and other unique nanostructured materials in the literature, our V2O5 nanofibers show much enhanced lithium storage capacity, improved cyclic stability, and higher rate capability. After 100 cycles at a current density of 800 mA g−1, the specific capacity of the V2O5 nanofibers retain 133.9 mAh g−1, corresponding to high capacity retention of 96.05%. More importantly, the EIS at various discharge depths clearly reveal the kinetics process of the V2O5 cathode reaction with lithium. Based on our results, the possible approach to improve the specific capacity and rate capability of the V2O5 cathode material is proposed. It is expected that this study could accelerate the development of V2O5 cathode in rechargeable lithium ion batteries.

•Mg/Al/La-layered double hydroxide (LDH) was synthesized with La/Al ratio 0.1.•Mg/Al/La-LDH was intercalated with sodium dodecyl sulfate.•The friction properties of intercalated product were superior to its precursor.•The mechanisms were sliding of laminates and the tribofilm formed on the surface.La-doped Mg/Al layered double hydroxide (LDH) was synthesized and intercalated by sodium dodecyl sulfate. Friction properties of LDHs as lubricant additives were evaluated in four-ball friction and air compressor test. The results showed that Mg/Al/La-LDH was prepared with La/Al molar ratio of 0.1. The interlayer spacing was expanded from 7.662 to 25.663 Å after intercalation. The intercalated product exhibited better tribological property than its precursor in the friction tests. The improved performance was attributed to a reduction in friction between the expanded laminates, good dispersion of the nanoparticles in the medium and an effective tribofilm formed on the contact surfaces.

La(OH)3 nanoparticles and serpentine/La(OH)3 composite particles were synthesized via sol–gel method. The phase compositions, micro-morphology of the synthesized particles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The tribological properties of different samples were tested and compared by the MM-10W Multi-functional friction abrasion tester and MHK-500 Ring-block wear testing machine. The TEM figure indicates that La(OH)3 nanoparticles are granular, the average size of the particles is 50 nm. The SEM figure of the composite particles illustrates that La(OH)3 particles uniformly coat on the surface of serpentine particles. The results of the friction tests indicate that serpentine, La(OH)3 and serpentine/La(OH)3 composite particles all exhibit friction-reducing and anti-wear properties compared to the base oil. The oil containing the composite particles have the best friction-reducing, anti-wear and self-repairing properties. The friction coefficients are reduced by 24.63% and the diameters of friction spots are reduced by 41.88% compared to the base oil. The energy spectrum of tribosurface gives evidence of that the contact area of rubbing pair was repaired by composite particles during friction tests.Highlights► We synthesized serpentine/La(OH)3 composite particles via sol–gel method. ► La(OH)3 nano-particles uniformly coat on the surface of serpentine particles. ► We test the tribological properties of La(OH)3, serpentine and their composite particles. ► The composite particles has the best friction-reducing, anti-wear and self-repairing properties. ► The lanthanum acted as catalyst to accelerate the reaction of the serpentine and the wear surface.

To uniformly encapsulate electrode materials with reduced graphene oxide (rGO) has been a considerable challenge due to the lack of appropriate synthetic methods and/or effective reaction systems. In this study, we present a one-step rapid and scalable solvothermal approach to achieve a crumpled reduced graphene oxide encapsulated VO2 material. As a demonstration of this promising configuration, for the first time, we systematically studied its Na+ storage behavior in the voltage range of 3.0 to 0.01 V (versus Na/Na+). It turned out that the as-prepared anode material exhibits high reversible capacities of 383 mA h g−1 at 0.1 A g−1 and 214 mA h g−1 at 4 A g−1, and can stably operate for as long as 2000 cycles at 4 A g−1 with a capacity fade of 0.013% per cycle, resulting from the improved electronic conductivity, structural stability, and electrode wettability. Furthermore, the formation mechanism and structural features of the desired crumpled reduced graphene oxide encapsulated VO2 material are discreetly expounded. More interestingly, a chain of cogent evidence is provided by coating on various electrode materials to confirm the scalability of this facile and rapid solvothermal synthesis method, which would open up a novel avenue to create more fascinating graphene-based functional materials for the multitudinous application domain.

Spinel Li4Ti5O12 performance highly depends on both the electronic and ionic conductivity, however, developing a low-cost strategy to improve its electronic and ionic conductivity still remains challenging. In this study, a facile cost-saving carbothermal reduction method is introduced to synthesize the microscaled spinel Li4Ti5O12 particles with the surface modification of Ti(III) using anatase–TiO2, Li2CO3, and acetylene black (AB) as precursors. Remarkably, this ingenious design can easily eliminate the influence of the residual carbon, and thus makes it possible to individually study the effect of the Ti(III) on the bulk Li4Ti5O12. To reveal the role of the Ti(III), the electronic conductivity and lithium-ion diffusion coefficient of the as-prepared materials were measured using a direct volt-ampere method, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The results indicate that the carbothermal reduction leads to the increased electronic and ionic conductivity of the spinel Li4Ti5O12. As a result, the modified Li4Ti5O12 exhibits an enhanced cyclic stability, improved rate capability, and high Coulombic efficiency. The carbothermal reduction mechanism discreetly clarified in this study is beneficial to improving Li4Ti5O12 performance for further commercial applications.