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MOF-derived XMn 2 O 4 (X = Zn, Co, Cu, Ni) nanomaterials achieve superior electrochemical performance for lithium storage. [Display omitted] • Two methods are proposed for the synthesis of XMn 2 O 4 (X = Zn, Co, Cu, Ni). • MOF-derived anodes exhibit excellent electrochemical capabilities compared with the ones obtained by simple coprecipitation. • Lithium storage capacity and rate performance of XMn 2 O 4 is best when X = Zn. • DFT calculations are performed to demonstrate that ZnMn 2 O 4 as an anode material is conducive to the diffusion of Li+. Bimetallic spinel transition metal oxides play a major part in actualizing eco-friendly electrochemical energy storage systems (ESSs). However, structural precariousness and low electrochemical capacitance restrict their actual implementation in lithium-ion batteries (LIBs). To address these demerits, the sacrificial template approach has been considered as a prospective way to strengthen electrochemical stability and rate performance. Herein, metal-organic frameworks (MOFs) derived XMn 2 O 4 -BDC (H 2 BDC = 1,4-dicarboxybenzene, X = Zn, Co, Cu, Ni) are prepared by a hydrothermal approach in order to discover the effects of various metal cations on the electrochemical performance. Among them, ZnMn 2 O 4 -BDC displays best electrochemical properties (1321.5 mAh g−1 at the current density of 0.1 A g−1 after 300 cycles) and high efficiency with accelerated Li+ diffusivity. Density functional theory (DFT) calculations confirm the ZnMn 2 O 4 possesses the weakest adsorption energy on Li+ with a minimized value of −0.92 eV. In comparison with other XMn 2 O 4 through traditional fabrication method, MOF-derived XMn 2 O 4 -BDC possesses a higher number of Li+ transport channels and better electric conductivity. This tactic provides a feasible and effective method for preparing bimetallic transition metal oxides and enhances energy storage applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A double-layer coating strategy is used to enhance the performance of SiO x anode. • The dual-shell structure consists of an Sn inner layer and N-doped outer layer. • The inner Sn can improve electronic conductivity and charge transfer kinetics. • The outer N-doped carbon shell can further maintain the structural integrity. • The dual-shell SiO x /C@Sn@NC anode exhibits excellent lithium storage ability. SiO x -based anode materials (0 < x < 2) have been regarded as an appealing candidate for anode material of commercial Lithium-ion batteries accounting for their ultrahigh theoretical capacity and low cost. However, its large-scale applications have been hampered by the serious volume expansion during repeated cycles, low intrinsic conductivity and unsatisfactory initial Coulombic efficiencies. Herein, to address these inherent deficiencies, a hierarchical SiO x -based anode with double-layer coatings of Sn inner layer and N-doped carbon outer shell is elaborately designed by a facile two-step hydrolysis process and polymer coating technology. Benefiting from the "synergistic effect" between Sn and SiO x at different working potentials and a well-designed double-layer coating structure, the resultant SiO x /C@Sn@NC anode displays excellent electrochemical properties, including an enhanced initial Coulomb efficiency (73.3%) efficiency, higher reversible capacity (991 mAh g−1) and superior long lifespan. Moreover, comprehensive characterization based on the reaction kinetics and structural stability proved that such enhanced ICE and cycling stability of anode material stem from its unique double-layer coating structure and multiple active components, which can significantly improve the diffusion of ion and charge transport, stabilize solid-electrolyte interphase (SEI) layer and absorb the expansion stress of electrode. Therefore, this study provides an efficient and feasible strategy to overcome the limitations of high-capacity SiO x -based anode materials via hybridization design with various active components and a double-layer coating strategy. [ABSTRACT FROM AUTHOR]

Attracted due to their potentially high theoretical capacities, storage redox activities, and diverse shape, cobalt phosphides (Co 2 P, CoP etc.) are thought to be the promising anodes for lithium-ion batteries (LIBs). Nevertheless, there still remain challenging bottlenecks of their low intrinsic conductivity and severe volume expansion when subjected to repeated electrochemical cycles, which unavoidably bring about structural collapse, active particle aggregation and rapid capacity degradation, and thereby poor long-term lifespan. Herein, we present a distinctively facile route and adopt metal-organic frameworks (MOFs) as the self-sacrificing hosts to construct carbon-encapsulated CoP/Co 2 P@N C composites which are composed of monodispersed electroactive Co x P (CoP/Co 2 P) nanoparticles encapsulated in carbon nanotubes (CNTs) based on N-doped carbon substrates. Remarkably, one exemplary CoP/Co 2 P@N C-600 electrode among them, when serves as anode for LIBs, exhibits high reversible capacity (977.9 mAh g−1, 100 cycles at 0.1 A g−1) and superior rate capability (639.7 mAh g−1 at 4 A g−1). Furthermore, an assembled LFP//CoP/Co 2 P@N C-600 full cell displays remarkable cycling performance. The more advantageous synergistic interaction of distinctive carbon-encapsulated architectures, robust N-doped carbon frameworks and electroactive components provides the fundamental foundation for superior lithium storage capabilities, where the synergistic interaction contributes towards enhancing electronic conductivity, offering extra electrochemical active sites, shortening the Li+/e− transport channels and alleviating volumetric variation. This contribution emphasizes the value of rationally designing MOF-derived carbon-encapsulated metal phosphide-based anodes for advanced LIBs. [ABSTRACT FROM AUTHOR]

SiO x is proposed as one of the most promising high-performance anodes for its favorable capacity and stable lithium insertion/extraction electric potential, however its effective commercial application still faces giant challenge. To overcome poor electrical conductivity and huge volume effect of silicon oxide-based material, we adopt a valid strategy to synthesis the SiO x nanosphere double-wrapped by MoS 2 and multi-walled carbon nanotubes (CNTs) as anode material. The influences of MoS 2 and CNTs on the structure, morphology and electrochemical performances of nanohybrid are probed detailly by transmission electron microscopy, X-ray photoelectron spectroscopy and charge-discharge measurements. The results show that as-prepared nanohybrids release a steady reversible capacity of 798 mAh g−1 with high capacity retention of 81.4% at 500 mA g−1 after 300 cycles. The outstanding electrochemical properties can be ascribed to the facts that the hollow mesoporous structure affords ample buffer space and the introduction of MoS 2 with a two-dimensional layered structure can provide more exposed active-sites for lithium adsorption, as well as the CNTs wrapping can form a favorable conductivity matrix, endowing the nanocomposites with great structural stability. Accordingly, this new structure design by means of a heterogeneous dual-wrapped architecture develops a significant strategy for the development of high-performance SiO x -based anode materials. Unlabelled Image • Heterogeneous dual-wrapped architecture of SiO x /MoS 2 -CNTs is successfully prepared. • The hollow structure shortens the transportation of Li+/e− and offers buffer space. • Wrapping MoS 2 can own more exposed active sites for promoting transport of Li+/e−. • The conductive twining CNTs form a favorable conductivity framework. • The material presents excellent cycling performance and rate capability. [ABSTRACT FROM AUTHOR]

The hollow Si nanospheres modified by the mechanically robust titanium dioxide (TiO 2 ) shell and the uniform carbon layer are intentionally designed and successfully prepared as the anode active material of high performance lithium-ion batteries. The effects of the robust TiO 2 shell and the uniform carbon layer on the structure and electrochemical performances for the Si@TiO 2 @C nanospheres are studied in detail by X-ray photoelectron spectroscopy, transmission electron microscopy, X-ray diffraction and charge/discharge tests. The results show that the hollow structure of the Si core can spontaneously absorb the huge volume expansion stress, the robust TiO 2 shell is used as a compact fence to promote the expansion towards the interior of the Si cavity instead of the exterior in the processes of charge/discharge, and the uniform carbon layer can effectively enhance the electrical conductivity and further control the integrity and stability of the well-wrapped core-shell-shell framework. Typically, the resultant hollow Si@TiO 2 @C nanospheres exhibit a high initial discharge capacity of 2557.1 mAh g −1 with coulombic efficiency of 86.06% as well as a large recuperative discharge capacity of 1270.3 mAh g −1 after 250 cycles at 1 A g −1 with a mean coulombic efficiency of 99.53%. Therefore, the hollow Si@TiO 2 @C nanospheres prepared by one-step sol-gel coating process show outstanding electrochemical properties and are considered as a prospective candidate to the adhibitions of the anode material for new generation power LIBs. [ABSTRACT FROM AUTHOR]

Abstract The hollow mesoporous silicon nanobox dually encapsulated by tin oxide and carbon layers is successfully fabricated and used for anode active material of lithium ion battery. The effects of the double coating layers on the structure, morphology and features of nanocomposite are systematically investigated by transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and galvanostatic charge-discharge tests. The results reveal that hollow mesoporous silicon/tin oxide/carbon nanobox has the adjustable void space and a rationally designed hierarchical structure, which permits the free expansion of Si core without breaking double coating layers and preserves the structural integrity of the electrode during the (de)lithiation processes, as well as significantly enhances the electronic conductivity of anode. As expected, the resultant hollow mesoporous silicon/tin oxide/carbon nanobox exhibits a high reversible capacity up to 1535 mAh g−1 at 0.5 A g−1 after 200 cycles of (dis)charging due to the unique nanostructure. Especially, the as-synthesized nanocomposite exhibits an excellent rate capacity as high as 858 mAh g−1 at 6 A g−1. This rational structure design and innovative approach can be of visible significance for the development of new anode active materials of next-generation lithium-ion battery. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

• Graphite was regenerated by acid leaching and graphene-like carbon coating. • The structure defects of graphite are well repaired. • The graphene-like carbon layer improves electrochemical performance of graphite. • The recycled graphite can meet the standard of commercial material. The recycling of waste electrode materials from spent lithium-ion batteries (LIBs) is attracting widespread attention from the perspective of the reutilization of resources and environment protection. Nevertheless, the low added value, complex separation steps and the structure defects induced in the long-term charge/discharge process reduce people's interest for secondary utilization of waste graphite anode. More importantly, if waste graphite anode is not prudently treated, it will cause black pollution. Herein, we report a facile and efficient graphene-like coating strategy for the regeneration of waste graphite. Using low-cost Humic Acid as the coated carbon source and waste graphite as the core, graphene-like-coated graphite anode material was prepared by sulfuric acid leaching and in situ carbonization of Humic Acid. Humic Acid containing aromatic rings can be in-situ converted to a graphene-like coating layer to repair the surface defects of graphite during thermal treatment, which can effectively restore the Li+ transport channels, improve the rate performance and cycle stability of the reconstructed graphite anode. When it is reused as anode material of LIBs, the reconstructed graphite anode shows a high initial Coulombic efficiency of 86.2 %, high capacity of 352.76 mAh/g and good retention capacity rate of 86.7 % after 400 cycles at 0.5C. Therefore, the graphene-like coating strategy provides a significant exploration for the recycling and regeneration of waste graphite anode materials, and it is conducive to the realization of the carbon peaking and carbon neutrality goals. [ABSTRACT FROM AUTHOR]

• Construct carbon protective shell to alleviate huge volume changes of Si. • Robust carbon framework can effectively maintains the structure integrity. • Carbon buffer layer can offer rich e-/ion channels to improve reaction kinetics. • The SCM electrode exhibited excellent electrochemical performance. Si-based anodes have revealed the potential as the next generation of lithium ion battery anode material, whereas the poor conductivity and huge volume changes during (de)lithiation process of silicon still limit their practical application. Herein, the Si/nitrogen doped carbon layer/carbon framework microspheres (SCM) are designed by nano-Si via electro-spray technology as anodes for lithium ion batteries. It has been found that the SCM consists of individual carbon-coated nano-Si primary particles linked by PAN framework, in which the carbon buffer layer can further absorb the stress of volume changes during charge/discharge process, and the carbon framework carbon framework not only provides fast diffusion path of electron, but also effectively reduces the consumption of electrolyte. Therefore, the initial columbic efficiency (ICE) of SCM anode can reach as high as 72%, and the SCM anode also shows a high specific capacity of 1192 mAh g−1 at 0.2 A g−1 and keeps a reversible capacity of 746 mAh g−1 after 200 cycles, demonstrating the as-designed SCM possesses an high ICE and a good electrochemical performance. This strategy provides a significant inspiration for fabricating high-performance Si/C anode materials of lithium-ion battery. [ABSTRACT FROM AUTHOR]

SiO x has aroused great attractions as a promising substitute for the anode materials of high-performance lithium-ion batteries (LIBs) because of the high specific capacity and the longer cycle life as well as relatively low volume expansion compared to Si. However, the unstable structure and poor conductivity of the SiO x lead to unideal electrochemical properties in LIBs, and thus hindering the widespread application of the SiO x anode. Herein, a facile approach has been put forward to prepare the high-performance mesoporous structure SiO x /carbon (m-SiO x /C) composites by electrospinning technique and sintering processes. The spherical SiO x nanoparticles are well anchored on the carbon fibers, and the reserved space can accommodate large volume expansion of the SiO x materials. Besides, the fibrous carbon materials can significantly enhance the conductivity for the SiO x anodes. Therefore, the resultant m-SiO x /C composites exhibit high discharge specific capacity of 1434 mAh g−1 at 500 mA g−1 with 67.5% capacity retention after 500 cycles and the good rate properties of 410 mAh g−1 at 2000 mA g−1. In consequence, the reasonable structural design and innovative fabrication technique can facilitate the practical application for the m-SiO x /C composites and further promote the comprehensive electrochemical performance of LIBs. [ABSTRACT FROM AUTHOR]

Oriented construction of high-performance mesoporous TiNb 2 O 7 (m-TNO) is important to the design innovation of anode material for next-generation lithium-ion batteries (LIBs) due to the high capacity and long cyclic life of m-TNO. However, the conductivity enhancement of m-TNO and thus accelerating Li+ transfer is still the key point to realize its practical application in LIBs. In this work, a synergistic strategy based on the single-core/dual-shell m-TNO@TiC@NC hierarchical structure is put forward, which is achieved by using m-TNO as host architecture as well as TiC and N-doped carbon layer (NC) as dual-shell layers. The results show that the m-TNO@TiC@NC hierarchical structure can not only provide an integrated conductive network to improve the conductivity of m-TNO, but also can establish a reinforced structure to maintain the anode stability. Besides, it is found that the m-TNO@TiC@NC composite has a high capacity of 328.6 mAh g−1 at 0.5 C after 200 cycles and a high-rate capacity of 186.4 mAh g−1 at 5 C by galvanostatic discharge-charge tests. Therefore, this kind of special single-core/dual-shell structure design can convincingly enhance the conductivity of m-TNO and facilitate the Li+ transfer rate, thus promoting electrochemical performances of LIBs due to the synergistic effect of dual-shell layers. Image 1 • The m-TNO@TiC@NC composite is achieved by using m-TNO as host architecture as well as TiC and NC as dual-shell layers. • The m-TNO@TiC@NC composite shows the single-core/dual-shell hierarchical structure. • The new-type ceramic material TiC is used as conducting layer. • The m-TNO@TiC@NC composite displays good electrochemical performance. [ABSTRACT FROM AUTHOR]

The activated carbon cloth (ACC@TNO) with flexible self-support structure, which is decorated by TiNb 2 O 7 (TNO) nanoparticle, is successfully obtained through hydrothermal reaction and calcination process in high temperature, and is used as the binder-free anode material of lithium ion batteries (LIBs). The morphology characteristic, pore structure properties and the phase structure of the ACC@TNO composites are detailedly studied by the scanning electron microscopy (SEM), Brunauer–Emmett–Teller adsorption/desorption measurement (BET) and X-ray diffraction (XRD). Meanwhile, the electrochemical properties of ACC@TNO composite are further tested by cyclic voltammetry and galvanostatic charge-discharge tests. As a result, the LIBs with ACC@TNO as anode material shows an initial discharge capacity of 356 mAh g−1 and an initial coulombic efficiency (ICE) of 87% at the current density of 0.5 C with the voltage window of 1.0–3.0 V. It also has been found that the reversible capacity can still keep as 290 mAh g−1 with the capacity retention of 81% after 500 cycles. Besides, when the cutoff voltage range is set to 0.01–3.0 V, the reversible capacity can reach 340 mAh g−1. Apparently, this work is of great significance for the exploration of the new anode materials with high performance and long cyclic life in next-generation LIBs. Image 1 • The ACC@TNO composite is obtained by epitaxially growing TNO particles on ACC surface like stab grown on the thorn. • The thiourea is use as a nitrogen source and sulfur source to treat the carbon cloth. • The ACC@TNO composite is binder-free anode material. • The ACC@TNO composite displays good electrochemical performance. [ABSTRACT FROM AUTHOR]