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A facile generic solvothermal strategy is employed to prepare C/SnOx/MoOy composite with evenly distributed C, Sn, Mo and O elements. The multi-element characteristic of active components and the introduction of carbon phase contribute greatly to the improved electrochemical performance as LIBs anodes. The influence of carbon phase and content of Sn and Mo on electrochemical behavior were investigated in this work. Carbon phase contributes greatly to the enhanced electric conductivity, structural integrity and pseudocapacitance contribution of the electrode. The best electrochemical performance is achieved in carbon/Sn–Mo oxide anode with a Sn/Mo ratio of about 1:1, indicating the mutual buffering relationship between Sn and Mo due to the different working voltage toward lithium. As a result, an excellent capacity retention of 98% (vs 2nd cycle) is delivered after 500 cycles at 0.5 A g−1. Even at a high rate of 2.0 A g−1, the capacity could be well remained after 500 cycles. Moreover, full cell employing such a C/SnOx/MoOy anode in combination with LiCoO2 cathode offers a good cycling performance. [ABSTRACT FROM AUTHOR]

Abstract Pseudocapacitive P-doped nickel cobaltate (P-NCO) porous microspheres were prepared via a two-step strategy. The P-NCO showed superior electrochemical performance than the pristine NiCo 2 O 4 as anode material for lithium ion batteries (LIBs). A reversible discharge capacity of 470 mAh g−1 can be maintained after 1000 cycles at a current density of 500 mA g−1, with an average capacity loss rate of 0.015% per cycle. The P-doped anode could deliver a reversible capacity of 496, 417, 303 and 210 mAh g−1 at 1.0, 2.0, 3.0 and 4.0 A g−1. Kinetic analysis revealed that pseudocapacitance plays a vital role in the lithium ion storage, which endows the P-NCO higher rate capacities and cycling stability. Attractive performance of the P-NCO anode is ascribed to the synergetic effect of porous structure and P-doping modification. The P-NCO demonstrates as a promising alternative to conventional anodes. Highlights • P-doped NiCo 2 O 4 has a capacity of 470 mAh g−1 after 1000 cycles at 500 mA g−1. • Pseudo-capacitance plays an important role in the lithium ion storage. • A possible mechanism of the attractive performance was put forward. [ABSTRACT FROM AUTHOR]

Commercialization of tin dioxide-based anodes for lithium-ion batteries has still not been achieved mainly due to the poor cycling performance caused by the huge volume changes of the electrodes. We herein synthesized a three-dimensional tin dioxide-graphene composite nanofiber (3D SnO/GNF) membrane via a hydrothermal and electrospinning method assisted by a subsequent calcination process. In this cross-linked three-dimensional network, SnO particles are loaded on the graphene crystal structure uniformly, with the aggregation and volume expansion partially inhibited. As a free-standing 3D network, the resultant nanofiber membrane could be used as the anode directly without the addition of the binder and conductive agent. Serving as a binder-free anode material for LIBs, the SnO/GNF anode exhibits good electrochemical performance with high reversible capacity and excellent cycling stability. More specifically, a high capacity of 763.9 mAh g was obtained at a current density of 100 mA g after 300 cycles. The extraordinary performance could be ascribed to the positive synergistic effect of the nanosized SnO particles and graphene. [ABSTRACT FROM AUTHOR]

Silicon/porous carbon nanofibers wrapped by reduced graphene oxide (Si/P-CNFs@rGO) are innovatively synthesized via a convenient preparation process consisting of a simple electrospinning method followed by a carbonization process and a sequent electrodeposition. Experimental results show that silicon nanoparticles (Si NPs) are anchored on the carbon fiber with rGO tightly wrapped on the fiber surface. This rGO protective layer acting as a dual-functional enhancer could not only accommodate the volume expansion of Si but also enhance the electrical conductivity, leading to an improved electrochemical performance. The as-obtained Si/P-CNFs@rGO electrode exhibits an excellent performance, with a high reversible capacity of 1851.3 mAh g at a current density of 0.2 A g with almost no capacity fading up to 50th cycle, a high reversible capacity of 1217.8 mAh g with an excellent coulombic efficiency (CE) of 99.0% at 0.53 A g after 300 cycles, and a high discharge specific capacity of 421.5 mAh g even at a high current density of 4 A g. [ABSTRACT FROM AUTHOR]

Silicon is regarded as one of the most promising candidates for lithium-ion battery anodes owing to its large theoretical energy density (about 4200 mAh g −1 ) and low working potential (vs. Li/Li + ). However, its practical application is limited by structure degradation and a comparatively poor capacity retention caused by large volume changes during cycling. In this study, we have prepared a novel nanofiber form of silicon/carbon with hollow core–shell structured silicon@carbon (Si@C) nanoparticles embedded in carbon nanofibers. Voids between the silicon nanoparticle (SiNP) core and carbon shell help to accommodate the volume expansion associated with the lithiation/delithiation process in a working electrode and allow formation of a stable solid electrolyte interphase (SEI) film. The obtained electrodes exhibited good cycle performance with a high reversible capacity of 1020.7 mAh g −1 after 100 cycles at a current density of 0.2 A g -1 , and also delivered excellent cycling performance at a high current density of 3.2 A g -1 . The design of this new structure provides a potential method for developing other functional composite anode materials with high reversible capacities and long-term cycle stabilities. [ABSTRACT FROM AUTHOR]

Novel sandwich-structured silicon-based anodes have been prepared to inhibit the fragmentation of silicon electrodes typically caused by the large volume changes that occur during charge/discharge processes. An electrostatic self-assembly method and hydrothermal dehydration are used to introduce a reduced graphene oxide layer (rGO) on the surface of silicon/carbon nanofibers (Si/CNFs), which prevent the exfoliation of nano-Si from the electrode bulk to the liquid electrolyte, reduce the electric contact loss, stabilize the electrode’s structural integrity, and improve electrochemical conductivity. The Si/CNFs@rGO exhibit superior electrochemical performance as an anode, retaining a high specific capacity of 1055.1 mAh g −1 up to 130 cycles at 0.1 A g −1 , with slight capacity loss. The Si/CNFs@rGO electrode also demonstrates outstanding rate behavior with a reversible capacity of 358.2 mAh g −1 at 5 A g −1 . Results indicate that the graphene layer significantly improves the electrochemical performance of the silicon/carbon nanofiber electrode. [ABSTRACT FROM AUTHOR]

Pyrolytic carbon-coated Si/C nanofibers (Si/C-CNFs) composites have been prepared through the sucrose coating and secondary thermal treatment of Si/CNFs composites produced via electrospinning and carbonization. This results in a structure in which Si nanoparticles are distributed along the fibers, with the fiber surface being coated with an amorphous carbon layer through pyrolysis of the sucrose. This carbon coating not only limits the volume expansion of the exposed Si nanoparticles, preventing their direct contact with the electrolyte, but also creates a connection between the fibers that is beneficial to Li + ion transport, structural integrity, and electrochemical conductivity. Consequently, the Si/C-CNFs composite exhibits a more stable cycle performance, better rate performance, and higher conductivity than Si/CNFs alone. The optimal level of performance was attained with a 20:200 mass ratio of sucrose to deionized water, with a high retained capacity of 1215.2 mAh g −1 after 50 cycles, thus indicating that it is a suitable anode material for Li-ion batteries. [ABSTRACT FROM AUTHOR]

Undoubtedly, silicon/carbon composites are one of the most promising anode classes for lithium-ion battery. However, they still suffer from poor cycle performance despite the introduction of carbon phase, which is usually expected to inhibit the volume expansion of Si phase and meanwhile enrich the electrode conductivity, improving the cycle stability. Here, a double-carbon protected silicon anode was designed and successfully synthesized through the liquid coating and in-situ polymerization method. In this structure, the primary seamless carbon layer make Si NPs maintain a close contact to conducting carbon, so that inserted Li+ could fully react with Si, improving the utilization of active materials. The secondary carbon skeleton could help to maintain the mechanical integrity of the structure and meanwhile enrich the charge transfer channels. The structural advantages enhance the mechanical integrity and electrochemical kinetics during cycling, that lead to superior electrochemical Li+ storage performance. The resulting double-carbon protected silicon anode demonstrates a high specific capacity, long-term stability (1919 mAh g−1 at 0.5 mA g−1, 90% retention after 400 cycles (vs. the capacity of second cycle)) and outstanding rate capability (1170 mAh g−1 at 2 A g−1). • Simple liquid coating and in-situ polymerization is used in this article. • Carbon source involved in the experiment is low-cost. • There are two different carbon phase in the Si@C@PC composite. • Excellent cyclic property is obtained for the double-carbon protected Si anode. [ABSTRACT FROM AUTHOR]

The low electrical conductivity and poor cycling stability at high current density of hausmannite (Mn 3 O 4) have greatly limited its practical application in commercial lithium ion batteries (LIBs). In order to tackle these above issues, porous carbon encapsulated Mn 3 O 4 has been designed and prepared. Carbon-encapsulated Mn 3 O 4 (Mn 3 O 4 @C) prepared via a MOF-derived strategy shows attractive cycling stability and rate performance in both half-cells and full cells. It could stably deliver a capacity of 730.20 mAh g−1 after 200 cycles at 250 mA g−1. An average capacity of 421 mAh g−1 is obtained at a current density of 4000 mA g−1. After a 400-cycle test at 2000 mA g−1, the Mn 3 O 4 @C anode can maintain 70.90% of its initial capacity. Full cells using Mn 3 O 4 @C as anode and NCM-523 as cathode could stably cycle for 100 times at 200 mA g−1, with a 73.30% capacity retention. Conversion mechanism of the Mn 3 O 4 @C anode has been investigated by ex-situ XPS. Upon the first discharge, Mn 3 O 4 is initially reduced into MnO and further reduced into metallic Mn0. The metallic Mn0 is then converted into MnO during the following charge. Subsequent lithiation/de-lithiation are governed by reversible conversion between MnO and metallic Mn0. Improved electrochemical performance of the Mn 3 O 4 @C anode is attributed to introduction of porous carbon, which could not only limit loss of active species but also enhance overall electrical conductivity. The Mn 3 O 4 @C composite can be a promising anode material for LIBs. Image 10987016 • Mn 3 O 4 @C composite is prepared via a MOF-derived strategy. • Mn 3 O 4 @C shows attractive electrochemical performance in both half cells and full cells. • Ex-situ XPS unveils the conversion mechanism between metallic Mn0 and MnO. [ABSTRACT FROM AUTHOR]

Transition metal oxide (TMO) is an important type of conversion reaction anode for lithium ion batteries. Carbon encapsulated zinc oxide and cobalt oxide (ZnO@C, Co 3 O 4 @C) were prepared via a MOF-derived strategy. MOF precursors were firstly coated with polypyrrole (PPy) layer and then subjected to subsequent thermal treatment. Benefiting from the synergetic effect of conductive coating layer and 3D porous structure, both anodes showed attractive electrochemical performance. The ZnO@C and Co 3 O 4 @C delivered a reversible capacity of 526 and 721 mAh∙g−1 after 500 cycles at 250 mA g−1. With attractive rate performance, the ZnO@C and Co 3 O 4 @C have an average capacity of 301 and 306 mAh∙g−1 at 2.0 A g−1. Kinetic analysis revealed that lithium ion storage in both ZnO@C and Co 3 O 4 @C were dominated by a surface controlled pseudo-capacitive process. In addition, ZnO@C and Co 3 O 4 @C could even stably cycle for 1000 times at a high current density of 2.0 A g−1. • ZnO@C and Co 3 O 4 @C were prepared via a facile MOF-derived strategy. • Both ZnO@C and Co 3 O 4 @C showed stably cycle for 1000 times at a high current density of 2.0 A g−1. • Lithium storage kinetics were investigated by in-depth analysis of CV curves collected at various scan rates. [ABSTRACT FROM AUTHOR]

Nickle foam-supported hierarchical ZnCo 2 O 4 nanosheets was prepared via a facile solution-based method. Porous ZnCo 2 O 4 nanosheets were in-situ grown on current collector, forming a binder-free electrode. When evaluated as anode for Lithium ion batteries (LIB S ), the binder-free electrode showed an attractive electrochemical performance. A reversible capacity of 773 mAh g −1 could be stably delivered after a 500-cycle test at a current density of 0.25 A g −1 , with a high capacity retention of 87%. The electrode could maintain a high reversible capacity of 245 mA h g −1 even at an elevated current density of 8.0 A g −1 . Integrated structure and rich porosity of the binder-free electrode were believed to contribute to the superior performance. Thus, the Nickle foam-supported ZnCo 2 O 4 electrode is a promising anode for high performance LIBs in the coming future. [ABSTRACT FROM AUTHOR]

A carbon-coated composite consisting of Sn, SnO 2 , and porous carbon-nanofiber membrane (Sn–SnO 2 –CNF@C) was successfully prepared via electrospinning followed by carbonization and low-temperature hydrothermal treatment. The thickness of the carbon overlayer formed by using sucrose as the carbon source could be well controlled by adjusting the sucrose concentration. The three-dimensional (3D) nanofiber network structure allowed the Sn–SnO 2 –CNF@C membrane to be used directly as an anode in lithium-ion batteries without adding any polymer binders or electrical conductors. The composite electrodes of this material exhibited a high discharge capacity of 712.2 mA h g −1 at a high current density of 0.8 A g −1 after 200 cycles, as well as good cycling stability and excellent rate capability, which can be ascribed to the improved electrochemical properties of the Sn–SnO 2 particles provided by the protective carbon coating and the 3D carbon nanofiber membrane. The composite can thus be widely used as an advanced binder-free anode material in high-current rechargeable lithium-ion batteries and extended to the fabrication of flexible electrodes. [ABSTRACT FROM AUTHOR]

To utilize the nanomaterials that could be mass manufactured for energy storage, a self-supported reduced graphene oxide (rGO) coated Cu 2 SnS 3 (CTS)/carbon nanofiber (CNF) electrode is fabricated by the facile gelation-solvothermal-electrodeposition method, and applied in lithium-ion batteries without a binder or conductive agent. Compared with the CTS microtubes synthesized from their complex template, the CTS nanoparticles in the rGO@CTS/CNF film are anchored on the CNF surface and surrounded by the conformal rGO with varying spacings. The whole self-supported rGO@CTS/CNF electrode (including the CNF and rGO) delivers an initial capacity of 678.8 mAh g−1 at 0.5 A g−1, and retains at 464.2 mAh g−1 after 200 cycles, which is superior to those of the pristine CTS microtubes and the uncoated CTS/CNF electrodes. Image 1 • The binder-free and self-supported CNF network, and rGO coated rGO@CTS composite. • The unique CTS microtubes are synthesized through the gelation-solvothermal process. • This work presents the carbon/CTS/carbon sandwich-structure electrode. [ABSTRACT FROM AUTHOR]

To develop next-generation lithium-ion batteries (LIBs) with novel designs, reconsidering traditional materials with enhanced cycle stability and excellent rate performance is crucial. We herein report the successful preparation of three-dimensional (3D) composites in which spilt Sn–Cu alloys are uniformly dispersed in an amorphous carbon nanofiber matrix (Sn–Cu–CNFs) via one-step carbonization-alloying reactions. The spilt Sn–Cu alloys consist of active Cu 6 Sn 5 and inactive Cu 3 Sn, and are controllable by optimization of the carbonization-alloying reaction temperature. The 3D carbon nanofiber framework allowed the Sn–Cu–CNFs to be used directly as anodes in lithium-ion batteries without the requirement for polymer binders or electrical conductors. These composite electrodes exhibited a stable cyclability with a discharge capacity of 400 mA h g −1 at a high current density of 1.0 A g −1 after 1200 cycles, as well as an excellent rate capability, which could be attributed to the improved electrochemical properties of the Sn–Cu–CNFs provided by the buffering effect of Cu 3 Sn and the 3D carbon nanofiber framework. This one-step synthesis is expected to be widely applicable in the targeted structural design of traditional tin-based anode materials. [ABSTRACT FROM AUTHOR]

• The novel thin film preparation technology through magnetron sputtering. • The unique binder-free ultrathin structure greatly improved the utilization ratio of active materials. • the binder-free SnS 2 electrode presents superior reversibility of conversion reaction. • The nanosized SnS 2 electrode exhibits high-rate performance because of the dominated pseudocapacitive effect. [Display omitted] To enhance the utilization of active materials and transform the traditional electrode preparation technology, a binder-free ultrathin SnS 2 anode for lithium ion batteries is fabricated through a simple magnetron sputtering method. In comparison with the electrode synthesized by solvothermal method and coating process, the binder-free SnS 2 electrode presents superior reversibility of conversion reaction due to the shorter ions and electrons transport path and the close contact of the active material with the electrolyte, suggesting a restraining effect on the tin agglomeration, then stabilize the electrode structure, it retains the superior capacity retention of 80% after 200 cycles at 0.5 A g−1 and the high rate capability of 788 mAh g−1 at 5.0 A g−1. The ultratiny SnS 2 nanoparticles uniformly arrayed on the substrate and occurred dominant pseudocapacitive effect, guaranteeing its high-rate performance with 967 mAh g−1 at 1.0 A g−1 after 200 cycles. The stable electrode morphology after cycling demonstrates its prospect for lithium ion batteries anode. [ABSTRACT FROM AUTHOR]