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The SnO 2 anode materials with various nanoparticle sizes were successfully synthesized to study their size effects on lithium storage performance. The compositions, structures, particle sizes and morphologies of the as-prepared samples were characterized by X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectroscopy (XPS), Scanning electron microscope (SEM) and high resolution transmission electron microscopy (HRTEM) techniques. It was confirmed that the obtained nanomaterials via a facile reflux approach show smaller size than that of hydrothermal method. Using cyclic voltammograms, electrochemical impedance spectroscopy, and galvanostatical charge/discharge testing, the SnO 2 anodes with different nanoparticle sizes exhibit various electrochemical performance with lithium, originating from the enormous volume changes associated with the alloying and de-alloying processes. It was demonstrated that the anode material with smaller nanoparticle size performs much better lithium storage performance. [ABSTRACT FROM AUTHOR]

SnO 2 has attracted intense interest for use as an anode material for lithium ion batteries because of various advantages of the high theoretical capacity and low-cost. Unfortunately, SnO 2 anode material suffers from the huge volume change and poor electrical conductivity. In order to address these problems, in this work, SnO 2 /graphene aerogel composites have been successfully synthesized by a facile hydrothermal approach. 3-4 nm-sized SnO 2 nanoparticles are uniformly dispersed over graphene aerogels. Our results indicate that the hydrothermal reaction time highly affects the electrode performance of the anodes. The nanocomposite electrode with reaction time of 3 h shows increased electrochemical performance with high energy capacity, long cycle life, and superior rate capability. After 100 cycles, it can deliver a high discharge capacity of 662 mAh g −1 at 100 mA g −1 . At 500 mA g −1 , it can still yield a discharge capacity of 619.7 mAh g −1 after 723 cycles. The performance improvement can attribute to the graphene aerogel, which can suppress the aggregation of SnO 2 nanoparticles, enhance the conductivity of SnO 2 , and increase their structural stability during cycling. This study strongly demonstrates that the SnO 2 /graphene aerogel composite is a promising anode material building high performance lithium ion batteries. [ABSTRACT FROM AUTHOR]

Li 3 P-VP nanocomposite has been formed by a homemade pulsed laser deposition route and its electrochemical characteristic with lithium is reported for the first time. It displays high lithium storage capability as electrode material for secondary lithium ion batteries. The Li 3 P-VP nanocomposite exhibits high specific discharge capacity of 1040.4 mAh g−1 between 0.01 and 4.0 V and the specific capacity can still maintain 95% after 50 cycles. Ex situ transmission electron microscopy reveals that VP 2 is generated from Li 3 P and VP after the first charging process to 4.0 V, while Li 3 P and V are found to be the final discharge products. In the recharging process, VP and VP 2 are formed as the delithiated products. Unlabelled Image • Li 3 P-VP nanocomposite thin film was fabricated by PLD. • High capacity of 1040.4 mAh g−1 was achieved and 95% was kept after 50 cycles. • VP 2 was generated from Li 3 P and VP after the first charging process to 4.0 V. • Reversible conversion mechanism to V and Li 3 P was suggested for VP-VP 2. [ABSTRACT FROM AUTHOR]

Abstract As the most promising anode material for next-generation Li batteries, Li metal never loses the academic attention due to its inherent superiority in high theoretical capacity and low redox potential. However, Li dendrites formed during cycling stubbornly hinder the pace of commercializing high-energy-density Li metal batteries. Here sericin endowed with abundant lithiophilic and anionphilic functional groups on its polypeptide chain is proposed as a conformal protective coating on both Cu and Li metal anodes. The resulting increase of Li-ion transference number (as high as 0.876) and mitigation of tip effect are favorable for the homogeneous Li deposition in island-like or lateral growth mode at electrode/electrolyte interface. Long cycle life (335 cycles) and high Coulombic efficiency (98%) are obtained in sericin decorated Li/Cu cells. Even under extremely high current density of 10 mA cm−2 based on a large capacity of 5 mAh cm−2, the sericin decorated Li anode also enables a superior cycle stability (160 cycles) in the symmetric cells. The conformal sericin coating effectively inhibits the corrosion of air to Li metal. Sericin modified Li-S batteries exhibit greatly enhanced rate performance (452.8 mAh g−1 at 5 C) and cycling performance (667.8 mAh g−1 after 520 cycles at 1 C). Graphical abstract Image 1 Highlights • Sericin is proposed as a conformal protective coating on both Cu and Li metal anodes. • Under 10 mA cm−2, the sericin decorated Li anode enables a superior cycle stability. • The conformal sericin coating effectively inhibits the corrosion of air to Li metal. • Sericin modified Li-S batteries exhibit enhanced rate and cycling performance. [ABSTRACT FROM AUTHOR]

Abstract Here, a high entropy oxide (HEO), Mg 0.2 Co 0.2 Ni 0.2 Cu 0.2 Zn 0.2 O, was explored as an anode material for lithium ion batteries. The HEO anode provides a high initial discharge specific capacity of about 1585 mAh g−1 and exhibits superior cycling stability. A reversible capacity of 920 mAh g−1 was achieved at 100 mA g−1 after 300 cycles. Ex situ scanning electron microscopy (SEM) and selected-area electron diffraction (SAED) revealed that the surface morphology and microstructure of the HEO anodes were still stable even after long term cycling. The well-mixed cations together with an inactive material (MgO, formed after the initial discharge process) in the HEO anodes result in a remarkable cycling, rate performance and an applicable reversible capacity with an average voltage of ∼0.85 V. This work may provide a convenient method for obtaining component-controlled oxide nanostructured materials with high electrochemical performance. Graphical abstract Image 1 Highlights • High entropy oxide was explored as an anode material for lithium ion batteries. • Well-mixed cations together with the inactive material result in a remarkable cycling performance. • A reversible capacity of 920 mAh g−1 can be achieved after 300 cycles. [ABSTRACT FROM AUTHOR]

High-entropy materials are recently attracted significant attention due to their variability of composition and entropy stabilizing phase structure. However, the current mainstream synthesis methods of high-entropy materials require high-energy ball milling and calcination, which limits their further generalization. In this work, a new class of high-entropy perovskite fluorides (HEPFs) as an anode material using for LIBs is reported. In particular, a high-entropy fluoride of KMgMnFeCoNiF 3 (TM5) and a series of medium-entropy fluorides (TM4) including KMnFeCoNiF 3 (TM4-Mg), KMgFeCoNiF 3 (TM4-Mn), KMgMnCoNiF 3 (TM4-Fe), KMgMnFeNiF 3 (TM4-Co), and KMgMnFeCoF 3 (TM4-Ni) are prepared by a facile ball milling with hydrothermal method. Interestingly, the TM5 electrode shows better cycling performance (120 mAh g−1 at 2 A g−1 over 1000 cycles with ∼99% coulombic efficiency) and rate performance (472–57 mAh g−1 at 0.1–3.2 A g−1 current densities) than TM4. The key to such improvement depends on the high-entropy effect together with the synergistic effects of multiple electroactive redox centers. It is believed that this work can provide a new idea for the design and synthesis of high-entropy perovskite materials in the future. [Display omitted] • The high and medium-entropy perovskite fluorides were synthesized by ball milling combined with the hydrothermal method. • The 3D octahedral framework is conducive to the diffusion of lithium ions for high-entropy perovskite fluoride. • The high ionic intrinsic diffusion coefficient improves the reaction kinetics of the high-entropy perovskite fluoride. • Owing to the high-entropy effect and multiple electroactive redox centers, it delivers a superior performance. [ABSTRACT FROM AUTHOR]

Graphene-based phosphorus-doped carbon (GPC) is prepared through a facile and scalable thermal annealing method by triphenylphosphine and graphite oxide as precursor. The P atoms are successfully doped into few layer graphene with two forms of P-O and P-C bands. The GPC used as anode material for Na-ion batteries delivers a high charge capacity 284.8 mAh g−1 at a current density of 50 mA g−1 after 60 cycles. Superior cycling performance is also shown at high charge−discharge rate: a stable charge capacity 145.6 mAh g−1 can be achieved at the current density of 500 mA g−1 after 600 cycles. The result demonstrates that the GPC electrode exhibits good electrochemical performance (higher reversible charge capacity, super rate capability, and long-term cycling stability). The excellent electrochemical performance originated from the large interlayer distance, large amount of defects, vacancies, and active site caused by P atoms doping. The relationship of P atoms doping amount with the Na storage properties is also discussed. This superior sodium storage performance of GPC makes it as a promising alternative anode material for sodium-ion batteries. [ABSTRACT FROM AUTHOR]

NiO–NiSe nanocomposite thin films are successfully fabricated by pulsed laser deposition (PLD) method and electrochemical properties of this composite are investigated by cyclic voltammetry and discharge/charge measurements. NiO–NiSe composite electrode delivers an initial discharge capacity of 577.7 mAh·g −1 and retains reversible capacity of 495 mAh·g −1 after 50 cycles, which exhibits significant improvement in cycling stability when compared with NiO thin film electrode. The electrochemical reaction mechanism of NiO–NiSe with lithium is examined by high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) techniques. The decomposition reactions of NiO–NiSe with Li to form metal Ni, Li 2 O and possible small nanosized Li 2 Se during discharge process, and the reformation of NiO–NiSe nanocomposite after charge process are revealed. [ABSTRACT FROM AUTHOR]

Three dimensional self-assembled graphene aerogel (GA) anode materials with some surface defects have been successfully generated through a facile hydrothermal procedure using graphene oxide as precursor. The morphologies and textural properties of as-obtained GA were investigated by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman and other spectroscopy techniques. The surface defects and electrical conductivities of GA can be controlled by adjusting the hydrothermal reaction time. The results indicate that GA with a reaction time of 6 h exhibits extremely high reversible capacity (1430 mAh g −1 at the current density of 100 mA g −1 ) and superior rate capability (587 mAh g −1 at 800 mA g −1 ) with excellent cycling stability (maintaining a reversible capacity of 960 mAh g −1 at 100 mA g −1 after 100 cycles). It is demonstrated that the 3D porous network with increased defect density, as well as the considerable electrical conductivity, results in the excellent electrochemical performance of the as-made GA anodes in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel three-dimensional tremella -like FeS/C microspheres, has been prepared. • The capacitive behavior of FeS/C were investigated. • The composite performs excellent capacitive and electrochemical performance. • The special structure is helpful to develop other multiple sulfides hybrid. In this work, a simple experimental method one-step hydrothermal method is made to prepare tremella-like FeS anchored into three-dimensional carbon (FeS/C) and get substantial progress in electrochemical properties and microstructure. The unique tremella-like structure is formed by the self-assembly of layered FeS/C, which would make the contact between the active material and the electrolyte sufficient, and maintain pronounced electrochemical performance. The studies show that the FeS/C synthesized is mainly dominated by the pseudocapacitive behavior in the electrochemical reaction processes, leading to fast the electrode reaction kinetics. The FeS/C anode also exhibits a large initial capacity of 619 mAh g−1 and remains 410.5 mAh g−1 with excellent rate performances. [ABSTRACT FROM AUTHOR]