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Nickel‐rich LiNi1−x−yCoxMnyO2 (NCM, 1−x−y ≥ 0.6) is known as a promising cathode material for lithium‐ion batteries since its superiority of high voltage and large capacity. However, polycrystalline Ni‐rich NCMs suffer from poor cycle stability, limiting its further application. Herein, single crystal and polycrystalline LiNi0.84Co0.07Mn0.09O2 cathode materials are compared to figure out the relation of the morphology and the electrochemical storage performance. According to the Li+ diffusion coefficient, the lower capacity of single crystal samples is mainly ascribed to the limited Li+ diffusion in the large bulk. In situ XRD illustrates that the polycrystalline and single crystal NCMs show a virtually identical manner and magnitude in lattice contraction and expansion during cycling. Also, the electrochemically active surface area (ECSA) measurement is employed in lithium‐ion battery study for the first time, and these two cathodes show huge discrepancy in the ECSA after the initial cycle. These results suggest that the single crystal sample exhibits reduced cracking, surface side reaction, and Ni/Li mixing but suffers the lower Li+ diffusion kinetics. This work offers a view of how the morphology of Ni‐rich NCM effects the electrochemical performance, which is instructive for developing a promising strategy to achieve good rate performance and excellent cycling stability. [ABSTRACT FROM AUTHOR]

Abstract Lithium ion capacitor (LIC) has been regarded as a promising device to combine the merits of high-energy lithium ion battery and high-power supercapacitor. The key challenge in developing high performance LIC is to achieve synergy between the high capacity of battery anode and the fast non-Faradaic reaction rate of capacitive cathode without compromising energy density. Here, we report 3D interconnected Fe 3 O 4 @C core@shell nanocomposites with enhanced lithium storage reaction kinetics as an anode material of LIC. Chitosan, a renewable biopolymer with rich functional groups, has been utilized as both structural directing agent and carbon precursor to assist the synthesis of Fe 3 O 4 @C composites, which have small particle size and an in-situ formed carbon coating layer. The carbon coating can not only dramatically improve the electronic conductivity, but also buffer the large volume expansion/contraction of Fe 3 O 4 during lithiation/delithiation. The Fe 3 O 4 @C composites show a reversible capacity of 1116.1 mA h g−1 at 0.1 A g−1 and 587.2 mA h g−1 at 2 A g−1, as well as stable capacity retention over cycling. Furthermore, the hybrid device based on Fe 3 O 4 @C composites achieves a specific energy of 110.1 Wh kg−1 at a specific power of 250 W kg−1, demonstrating promising application of the reported hybrid systems. Graphical abstract A lithium ion battery and supercapacitor hybrid device has been constructed with novel designed 3D interconnected Fe 3 O 4 @C anode prepared using chiotsan biopolymer, which combines high energy density and high power density simultaneously. The hybrid device achieves an exceptional energy density of 110.1 Wh kg−1 at a specific power of 250 W kg−1 with outstanding capacity retention. Image 1 [ABSTRACT FROM AUTHOR]

Abstract: The lithium‐ion capacitor (LIC) has been regarded as a promising device that combines the merits of lithium‐ion batteries and supercapacitors, and that meets the requirements for both high energy and high power density. The development of advanced electrode materials is the key requirement. Herein, we report the bottom‐up synthesis of activated carbon nanofiber (a‐PANF) with a hierarchical porous structure and a high degree of graphitization. Electrospinning has been employed to prepare an interconnected fiber network with macropores, and ferric acetylacetonate has been introduced as both a mesopore‐creating agent and a graphitic catalyst to increase the degree of graphitization. Furthermore, chemical activation enlarges the specific surface area by producing abundant micropores. Half‐cell evaluation of the as‐prepared a‐PANF gave a discharge capacity of 80 mA h g−1 at 0.1 A g−1 within 2–4.5 V and no capacity fading after 1000 cycles at 2 A g−1, which represents a significant improvement compared to conventional activated carbon (AC). Furthermore, an as‐assembled LIC with a‐PANF cathode and Fe3O4 anode showed a superior energy density of 124.6 W h kg−1 at a specific power of 93.8 W kg−1, which remained at 103.7 W h kg−1 at 4687.5 W kg−1. This indicates promising application potential of a‐PANF as an electrode material for efficient energy storage systems. [ABSTRACT FROM AUTHOR]

Graphene-containing nanomaterials have emerged as important candidates for electrode materials in lithium-ion batteries (LIBs) due to their unique physical properties. In this review, a brief introduction to recent developments in graphene-containing nanocomposite electrodes and their derivatives is provided. Subsequently, synthetic routes to nanoparticle/graphene composites and their electrochemical performance in LIBs are highlighted, and the current state-of-the-art and most recent advances in the area of graphene-containing nanocomposite electrode materials are summarized. The limitations of graphene-containing materials for energy storage applications are also discussed, with an emphasis on anode and cathode materials. Potential research directions for the future development of graphene-containing nanocomposites are also presented, with an emphasis placed on practicality and scale-up considerations for taking such materials from benchtop curiosities to commercial products. [ABSTRACT FROM AUTHOR]

Li 4 Ti 5 O 12 (LTO) based batteries have severe gassing behavior during charge/discharge and storage process. The interfacial reactions between LTO and electrolyte solution may be the main reason. In this work, the LTO spinel particles are modified with ZnO coating using a chemical process to reduce the surface reactivity of LTO particles. Results show that the ZnO coating can effectively stabilize the electrode/electrolyte interface and suppress the formation of a solid electrolyte interface (SEI) film. Simultaneously, this ZnO modification can improve the electronic conductivity and lithium ion diffusion coefficient, which contributes to a great improvement in cyclic and high rate capabilities of LTO electrode. The ZnO coating on LTO may be an effective method to restrict the gassing behavior of LTO based battery. [ABSTRACT FROM AUTHOR]

Graphene‐containing nanomaterials are promising candidates for electrode materials in next‐generation energy storage devices, particularly in Li‐ion batteries for electric vehicles. In article number 1500400, Songping Wu, Zhiqun Lin, and co‐workers highlight the variety of synthetic strategies for nanoparticles/graphene composites. The limitations of these materials for energy storage applications are also discussed and potential research directions for their future development are presented. [ABSTRACT FROM AUTHOR]

The antimony oxide/reduced graphene oxide (Sb 2 O 3 /rGO) nanocomposites are used as anode of Li-ion and Na-ion batteries (LIBs and NIBs). However, it is unclear about Li-ion and Na-ion storage mechanism in Sb 2 O 3 /rGO nanocomposites. Herein, the conversion-alloying mechanisms of Sb 2 O 3 /rGO anodes for Na-ion and Li-ion storage are comparatively studied with a combined in-situ XRD and quasi in-situ XPS method. The distinct behaviours are monitored during (de)lithiation and (de)sodiation with respect to crystal structure and chemical composition evolution. It is evidenced that the Na-ion can be easily transported to the inner part of the Sb 2 O 3 , where the Li-ion almost cannot reach, leading to a fully transformation during sodiation. In addition, the conversion reaction product of amorphous Na 2 O display their better chemical stability than amorphous Li 2 O during electrochemical cycles, which contribute to a stable and long cycling life of NIBs. This work gain insight into the high-capacity anodes with conversation-alloying mechanism for NIBs. [ABSTRACT FROM AUTHOR]

Template method has been used as an important method to prepare porous materials. However, there are few reports about template method employing potassium chloride as template. Here, potassium chloride is employed as a template to prepare the porous carbon, and transition metal nitrates (Fe(NO 3 ) 2 ,d Co(NO 3 ) 2 , Ni(NO 3 ) 2 ) are introduced to catalyze graphitization and to result different carbon structure during carbonization (denoted as Fe@C, Co@C and Ni@C). The Fe@C shows a formicary-like structure with an about 20 nm pore diameter and the Co@C displays a completely compact structure. Whereas, the Ni@C exhibits a foam-like structure with hierarchical porous structure consisting of macroporous frameworks, mesopores and ultrathin porous walls (∼5 nm). Its macropore and mesopore diameter is around 100 nm and 4 nm, respectively, its specific surface area is 464.5 m 2  g −1 . When adopted as anode material, the Ni@C presents much outstanding rate and cycling capability for lithium and sodium storage than Fe@C and Co@C, the capacity for sodium storage is 260 mAh g −1 after 100 cycles at 100 mA g −1 and 92 mAh g −1 after 1000 cycles at 1A g −1 , and the capacity for lithium storage is 683 mAh g −1 after 1000 cycles at a current density of 1 A g −1 . [ABSTRACT FROM AUTHOR]

The silicon/carbon (Si/C) hybrid fibers with a hierarchical core–shell structure are prepared by encapsulating Si nanoparticles in the interconnected hollow carbon fibers (Si@IHCFs) based on a dual coaxial electrospinning technique. For the hierarchical structure, Si nanoparticles are embedded in the honeycomb-like carbon framework in the fiber core, which is further wrapped by the interlocked cobweb-like carbon shell network. As lithium-ion battery anode, the well-defined Si@IHCFs demonstrates a reversible capacity of 903 mAh g −1 and a capacity retention of 89% after 100 cycles with a current density of 0.2 A g −1 . With the current density gradually increasing to 2.0 A g −1 , the electrode shows a specific capacity of 743 mAh g −1 , exhibiting superior rate capability compared to the Si/C fibers with a core–shell but unconnected structure. The excellent electrochemical properties are attributed to the hierarchical core–shell structure and cross-linked network for the Si/C composite fibers. The carbon framework in the core region accommodates the volume expansion of Si by the honeycomb-like pores. And the interconnected carbon shell can not only prevent electrolyte from permeating into the core section, but also improve the electronic conductivity by the connections in the fiber network. [ABSTRACT FROM AUTHOR]

Fe 3 O 4 nanoparticles encapsulated in porous carbon fibers (Fe 3 O 4 @PCFs) as anode materials in lithium ion batteries are fabricated by a facile single-nozzle electrospinning technique followed by heat treatment. A mixed solution of polyacrylonitrile (PAN) and polystyrene (PS) containing Fe 3 O 4 nanoparticles is utilized to prepare hybrid precursor fibers of Fe 3 O 4 @PS/PAN. The resulted porous Fe 3 O 4 /carbon hybrid fibers composed of compact carbon shell and Fe 3 O 4 -embeded honeycomb-like carbon core are formed due to the thermal decomposition of PS and PAN. The Fe 3 O 4 @PCF composite demonstrates an initial reversible capacity of 1015 mAh g −1 with 84.4% capacity retention after 80 cycles at a current density of 0.2 A g −1 . This electrode also exhibits superior rate capability with current density increasing from 0.1 to 2.0 A g −1 , and capacity retention of 91% after 200 cycles at 2.0 A g −1 . The exceptionally high performances are attributed to the high electric conductivity and structural stability of the porous carbon fibers with unique structure, which not only buffers the volume change of Fe 3 O 4 with the internal space, but also acts as high-efficient transport pathways for ions and electrons. Furthermore, the compact carbon shell can promote the formation of stable solid electrolyte interphase on the fiber surface. [ABSTRACT FROM AUTHOR]

A Li-ion capacitor (LIC) is constructed with Li 4 Ti 5 O 12 /C hybrid as the negative electrode and 3D porous graphene macroform (PGM) as the positive electrode. After optimizing the mass ratio (m + /m − ) of the electrode materials with the value of 2, the as-fabricated LIC delivers a maximum energy density of 72 Wh kg −1 with the power density of 650 W kg −1 in a voltage range of 1.0–3.0 V. Furthermore, the energy density of the LIC reaches 40 Wh kg −1 even at a high power density of 8.3 kW kg −1 . More significantly, the LIC exhibits a good cycling stability with the retention of 65% after 1000 cycles at a high current density of 10 A g −1 , suggesting great potential application in energy storage of the LIC. [ABSTRACT FROM AUTHOR]