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To design a high‐performance Fe2O3‐based anode for Li‐ion batteries (LIBs), Fe2O3 nanocubes (Fe2O3–NCs) and their graphite‐modified (Fe2O3–NCs–G) composite were synthesized using a simple two‐step method. The Fe2O3–NCs–G composite consisted of homogeneously distributed individual Fe2O3–NCs with graphite matrices, which were confirmed by X‐ray diffraction (XRD) and scanning electron microscopy. In addition, the Fe2O3–NCs–G composite delivered a high specific surface area and good electrical conductivity. To demonstrate the electrochemical Li insertion/extraction mechanism of the Fe2O3–NCs–G composite electrodes, ex‐situ XRD and Fe K‐edge extended X‐ray absorption fine structure analyses were performed. Because of its structural merits, the synthesized Fe2O3–NCs–G composite exhibited high electrochemical performance featuring a high reversible capacity of 865 mAh g−1 after 100 cycles and a fast rate capability, thus demonstrating its high possibility for high‐performance LIBs. [ABSTRACT FROM AUTHOR]

A nanostructured FeSn 2 /SnO 2 composite was directly synthesized using a simple solid-state ball milling synthesis method by exploiting the disproportionation reaction of SnO and the thermodynamically stable formation of FeSn 2. The as-synthesized FeSn 2 /SnO 2 composite comprised small (∼10–20 nm) FeSn 2 and SnO 2 nanocrystallites, and as a lithium-ion battery anode, it exhibited better electrochemical performance than FeSn 2 and SnO 2. Furthermore, we prepared a C-decorated FeSn 2 /SnO 2 (FeSn 2 /SnO 2 /C) composite. Compared to FeSn 2 /SnO 2 , FeSn 2 /SnO 2 /C contained smaller nanocrystallites of FeSn 2 (∼10 nm) and SnO 2 (∼5 nm), which were present in the amorphous C matrix and provided enhanced electrochemical performance. The FeSn 2 /SnO 2 /C composite had a high reversible initial capacity of 843 mAh·g−1, a stable capacity retention of above 80% after 100 cycles, and a high C-rate performance of ∼610 mAh·g−1 at 3C rate. Moreover, its electrochemical reaction mechanism during lithium insertion/extraction was determined by ex situ extended X-ray absorption fine structure analysis. Owing to their high electrochemical performance, FeSn 2 /SnO 2 /C composites are promising as a new high-performance anode material for lithium-ion batteries. Image 1 • FeSn 2 /SnO 2 -based nanocomposites are synthesized by a simple solid-state ball milling. • A FeSn 2 /SnO 2 /C composite contains small FeSn 2 and SnO 2 nanocrystallites. • The FeSn 2 /SnO 2 /C composite is tested for its suitability as Li-ion battery anodes. • The FeSn 2 /SnO 2 /C composite exhibits excellent electrochemical performances. [ABSTRACT FROM AUTHOR]

To design high performance SiO 2 -based anodes for Li-ion batteries (LIBs), an amorphous SiO 2 -FeSi-graphite ( a -SiO 2 /FeSi/G) composite was synthesized by a simple solid state synthetic method using SiO, Fe, and graphite powders. The a -SiO 2 /FeSi/G composite was comprised of well dispersed amorphous SiO 2 and tiny (5–10 nm sized) FeSi inactive matrices within the graphite buffering matrices. The a -SiO 2 /FeSi/G composite electrode showed excellent electrochemical performance featuring high initial charge capacity of 729 mAh g −1 , with high initial Coulombic efficiency of approximately 74%, and long capacity retention of 93.7% after 200 cycles, with a highly reversible capacity of 683 mAh g −1 . [ABSTRACT FROM AUTHOR]

Well-dispersed Fe 3 O 4 nanoparticles (around 10–20 nm) were simply produced by mechanochemical transformation of iron oxyhydroxides (FeO(OH)). When the Fe 3 O 4 nanoparticles were applied as anodes for rechargeable Li-ion batteries (LIBs), excellent electrochemical performance was observed with highly reversible capacities of 914 mAh g −1 over 120 cycles and fast rate capability. The metal oxides produced by mechanochemical transformation of metal oxyhydroxides will be highly applicable to electrodes for high-performance LIBs. [ABSTRACT FROM AUTHOR]

Abstract: Zinc selenide (ZnSe; mineral name: stilleite) and its nanostructured composite (ZnSe/C) are prepared by simple solid-state synthetic routes, and their potential as electrode materials for rechargeable Li-ion batteries is investigated. The reaction mechanism between ZnSe and Li is demonstrated using ex situ X-ray diffraction and extended X-ray absorption fine structure analyses. The X-ray diffraction patterns and high-resolution transmission electron microscopy observations confirm that ZnSe nanocrystallites in ZnSe/C are uniformly distributed within an amorphous carbon matrix. The nanostructured ZnSe/C composite electrode exhibit excellent electrochemical performances such as a high capacity and long cycling behavior of ca. 705 mAh g−1 over 300 cycles. [Copyright &y& Elsevier]

By using carbon nanotubes (CNTs) as a shape template and glucose as a carbon precursor and structure-directing agent, CNT@Fe3O4@C porous core/sheath coaxial nanocables have been synthesized by a simple one-pot hydrothermal process. Neither a surfactant/ligand nor a CNT pretreatment is needed in the synthetic process. A possible growth mechanism governing the formation of this nanostructure is discussed. When used as an anode material of lithium-ion batteries, the CNT@Fe3O4@C nanocables show significantly enhanced cycling performance, high rate capability, and high Coulombic efficiency compared with pure Fe2O3 particles and Fe3O4/CNT composites. The CNT@Fe3O4@C nanocables deliver a reversible capacity of 1290 mA h g−1 after 80 cycles at a current density of 200 mA g−1, and maintain a reversible capacity of 690 mA h g−1 after 200 cycles at a current density of 2000 mA g−1. The improved lithium storage behavior can be attributed to the synergistic effect of the high electronic conductivity support and the inner CNT/outer carbon buffering matrix. [ABSTRACT FROM AUTHOR]

Highlights: [•] An amorphized composite, Sb/Al2O3/C, is simply prepared by a straightforward mechanochemical reduction method. [•] Various analytical tools reveal that the composite is composed of amorphized Sb, amorphous Al2O3, and carbon. [•] The amorphized composite is investigated for use as an anode material for rechargeable Li-ion batteries. [•] The composite electrode shows a high energy density of more than 1800mAhcm−3 over 300 cycles. [Copyright &y& Elsevier]

Abstract: An Sb-based nanostructured composite with embedded TiO2 was prepared from Sb2O3, Ti, and carbon powders using a mechanochemical reduction method and was evaluated as an anode material in rechargeable Li-ion batteries. X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy analyses reveal that the Sb/TiO2/C nanocomposite is composed of nanocrystalline Sb, rutile-TiO2, and amorphous carbon. Electrochemical tests show that the electrochemical performance of the Sb/TiO2/C nanocomposite electrode is superior to that of the pure Sb electrode. [Copyright &y& Elsevier]

Abstract: An anode material with improved electrochemical performances for Li-ion batteries is prepared using the disproportionation reaction of SiO followed by a high energy mechanical milling process. The modified SiO is composed of embedded Si nano-crystallites in a Si-oxide matrix. Si-oxide matrix could be divided into two parts by reactivity with Li-ion. The inactive Si-suboxide matrix would buffer the volume expansion of embedded Si nano-crystallites and active amorphous SiO2 during the lithiation. This modified SiO electrode shows a large reversible capacity, close to 1000 mAh g−1, and good cyclability, over 50 cycles. [Copyright &y& Elsevier]

Cobalt oxide-based nanocomposites are prepared using CoO, various metals (Al, Mg), carbon powders, and a simple high-energy mechanical milling technique. X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy show that the cobalt oxide-based composites are mainly composed of nanostructured CoO/AlO, CoO/MgO, and CoO/C composites, respectively. Based on concepts related to the enhanced electrical conductivity of the CoO/C nanocomposite using conducting carbon matrix and to the resistance of inactive ceramic matrices (AlO, MgO) against active CoO particle growth during cycling, various nanostructured cobalt oxide-based composites are tested for use as anode materials. Among the composites, the CoO/C nanocomposite anode exhibits good electrochemical characteristics, such as high-capacity, good initial Coulombic efficiency, and long cycle behavior for Li-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: The electrochemical behaviors of pyrolized polyacrylonitrile (PAN) were investigated to be applied as a carbon source in a metal–carbon composite anode in Li-ion batteries. Pyrolized PAN showed a porous structure with a reversible capacity approximately 300mAhg−1. A pyrolyzed PAN based Sn/C composites were synthesized from SnO and PAN using a high energy ball milling followed by carbothermal reduction, and the Sn particles with diameters of 100–200nm were randomly embedded on the carbon matrix. The composite electrode exhibited a relatively large capacity and an excellent cycle behavior. The enhanced electrochemical performances of this composite were attributed to the role as a matrix and porous nature of pyrolyzed PAN which accommodated a large volume expansion of the Sn during the reaction with Li, the increased electrical conductivity of pyrolyzed PAN and the uniformly dispersed nanometer sized Sn that formed during the cycling. [Copyright &y& Elsevier]

Abstract: The suitability of silver sulfide (Ag2S) and its nanocomposite Ag2S/C, prepared by simple solid-state synthetic routes such as high-energy mechanical milling and heat treatment, for use as anode materials in rechargeable Li-ion batteries has been investigated. A well-developed Ag2S phase is identified from X-ray diffraction (XRD) patterns, and XRD and high-resolution transmission electron microscopy observations confirm that Ag2S nanocrystallites in Ag2S/C are uniformly distributed within an amorphous carbon matrix. The electrochemical reaction mechanism of Ag2S with Li is identified by ex situ XRD analyses of an Ag2S/C nanocomposite electrode. The Ag2S/C nanocomposite anode shows good cycling behavior and a high capacity of about 430mAhg−1 after 100cycles. [Copyright &y& Elsevier]

Abstract: The electrochemical behavior of the SiO (silicon monoxide) anode during its reaction with Li has been investigated using solid-state nuclear magnetic resonance (NMR) and high resolution transmission electron microscopy (HRTEM). It was mainly focused on identifying the intermediate and final phases formed with their microstructures of the electrochemically lithiated SiO at various voltage steps during the first cycle. A model for the reaction of SiO with lithium was suggested, which was consistent with the discharge capacity of about 2400mAhg−1. [Copyright &y& Elsevier]

Abstract: Bi2S3 and Bi2S3/C nanocomposites prepared by high-energy mechanical milling were evaluated as electrode materials in lithium secondary batteries. For a Bi2S3/C nanocomposite, Bi2S3 nanocrystallites were well distributed in an amorphous carbon matrix. The reaction mechanism of the Bi2S3/C electrode was also examined during the first cycle. The Bi2S3/C nanocomposite anode showed superior electrochemical performance (ca. 500mAhg−1 and 85% of the capacity retention over 100 cycles). [Copyright &y& Elsevier]

Abstract: Intermetallic FeSb2 and CrSb2 and their nanocomposites (FeSb2/C and Sb/Cr3C2/C) were prepared using solid-state routes, such as heat-treatment and high-energy mechanical milling, in order to enhance the electrochemical properties of Sb. These electrodes were tested as anode materials for rechargeable Li-ion batteries. The reaction mechanism of intermetallic FeSb2 and CrSb2 was investigated using ex situ X-ray diffraction and high resolution transmission electron microscopy. The FeSb2/C and Sb/Cr3C2/C nanocomposite electrodes exhibited greatly enhanced electrochemical behaviors compared to the FeSb2 and CrSb2 electrodes. Additionally, the Sb/Cr3C2/C nanocomposite electrode showed a better electrochemical performance than the FeSb2/C nanocomposite electrode. [Copyright &y& Elsevier]

Abstract: A Ge/Cu3Ge/C composite, prepared by pyrolysis and a high energy mechanical milling process, was investigated as an anode material for Li-ion batteries. Electron probe micro-analyzer images showed that Ge and Cu3Ge were well dispersed in the carbon matrix. Various analytical techniques were carried out to clarify the reaction mechanism of the Cu3Ge single phase and the Ge/Cu3Ge/C composite ex situ XRD and ex situ HRTEM analyses for Ge/Cu3Ge/C composite electrode were carried out and the final phase formed was Li15Ge4. For the case of pure Cu3Ge electrode, it reacted with Li at very low rate and the final product was probably a Li–Ge compound. Electrochemical tests showed that the Ge/Cu3Ge/C composite exhibited better capacity retention than that of the Ge/C composite anode probably due to the presence of amorphous carbon which acted as a buffering matrix during volume expansion and Cu that formed during the first discharge increased the electrical conductivity locally. [Copyright &y& Elsevier]

Intermetallic TiSb2 and Sb/TiC/C nanocomposites were prepared by alloying and dealloying reactions, respectively, and their potential as anode materials for rechargeable Li-ion batteries was investigated. The Sb/TiC/C nanocomposite was composed of nanocrystalline Sb and TiC, which were distributed uniformly in an amorphous carbon matrix. The reaction mechanism of intermetallic TiSb2 with Li was examined by ex Situ X-ray diffraction and high resolution transmission electron microscopy. The Sb/TiC/C nanocomposite exhibited good electrochemical performance, such as a high initial coulombic efficiency of 87% and a long cycle retention of 83% after 100 cycles.d. [ABSTRACT FROM AUTHOR]

Abstract: A nanostructured Sn/TiO2/C composite was prepared from SnO, Ti, and carbon powders using a mechanochemical reduction method and evaluated as an anode material in rechargeable Li-ion batteries. The Sn/TiO2/C nanocomposite was composed of uniformly dispersed nanocrystalline Sn and rutile TiO2 in amorphous carbon matrix. In addition, electrochemical Li insertion/extraction in rutile TiO2 was examined by ex situ XRD and extended X-ray absorption fine structure. The Sn/TiO2/C nanocomposite exhibited excellent electrochemical performance, which highlights its potential as a new alternative anode material in Li-ion batteries. [Copyright &y& Elsevier]

Abstract: At present, graphite (LiC6: 372mAhg−1, 840mAhcm−3) is used as the anode material for lithium-ion batteries. However, methods to enhance the energy density, cyclability, initial Coulombic efficiency, and rate capability of lithium-ion batteries are still actively being researched. Here, we report a simple, fast, and novel method for transforming micron-sized Sn and Sb powders into ca. 10nm- and 2–3nm-sized SnSb crystallites by mechanochemical synthesis and electrochemical reactions, respectively. These nanocrystallites are uniformly distributed in an amorphous carbon matrix, resulting in a SnSb/C nanocomposite structure. The fabricated SnSb/C nanocomposite showed excellent electrochemical properties, such as a high energy density (1st charge: 706mAhg−1), long cyclability (ca. 550mAhg−1 over 300 cycles), good initial Coulombic efficiency (ca. 81%), and a fast rate capability (1C: 590mAhg−1, 2C: 550mAhg−1). [Copyright &y& Elsevier]

Abstract: Nanostructured Bi/C and Bi/Al2O3/C composites, prepared by high-energy mechanical milling (HEMM), are investigated as anode materials for Li-ion rechargeable batteries. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) reveal that the Bi/C nanocomposite is composed of nano-sized Bi and amorphous C, while the Bi/Al2O3/C nanocomposite (obtained by the mechanochemical reduction of Bi2O3 and Al) is composed of nano-sized Bi, amorphous Al2O3, and amorphous C. The electrochemical reaction mechanism of the Bi/C nanocomposite electrode is identified by ex situ XRD analyses combined with a differential capacity plot. Electrochemical tests show that the Bi/C and Bi/Al2O3/C nanocomposites exhibit enhanced electrochemical performances compared with that of the pure Bi electrode. [Copyright &y& Elsevier]

Abstract: A Si–Zn–C composite material is prepared by mechanical ball-milling and investigated as an anode material for lithium-ion batteries. Electrochemical tests show that the first charge and discharge capacities are approximately 852 and 607mAhg−1, respectively, and that 91% of the initial discharge capacity of 607mAhg−1 can be maintained for up to 40 cycles. This improved cycling performance is attributed to the use of the third element Zn. Li2ZnSi is partially formed at the interface between Si and Zn and graphite to provide superior cycling performance compared with that of the binary system. [Copyright &y& Elsevier]

Abstract: An Mg–C composite, prepared by high energy mechanical milling, was investigated as an anode material for lithium-ion batteries. Electrochemical tests demonstrated that the first charge and discharge capacities were 1810 and 1433mAhg−1, respectively, with a coulombic efficiency for the first cycle of 80%. Ex situ XRD analyses combined with a differential capacity plot of the Mg–C composite electrode showed the phase changes during the electrochemical Li–Mg alloying/dealloying reaction. Significantly enhanced rate capability and reversibility of the electrochemical reaction of Mg with lithium were observed and the improvement in the electrochemical properties of the composite electrode was attributed to the high energy mechanical milling of Mg with carbon on the surface of the Mg–C composite. [Copyright &y& Elsevier]

Here, we report a simple, cheap, and rapid synthesis method combined with physical and chemical routes for porous structured metal-based carbon nanocomposites, which can be applicable to anode materials for high performance Li-ion batteries. [ABSTRACT FROM AUTHOR]

A two-dimensional layered Sb 2 Se 3 -based amorphous composite (a –Sb 2 Se 3 /C) is synthesized using a simple solid-state ball-milling process, and its potential for Li- and Na-ion batteries is evaluated. Ex situ extended X-ray absorption fine structure analyses clearly indicate the electrochemical reaction mechanisms of Sb 2 Se 3 and a –Sb 2 Se 3 /C as anodes for Li- and Na-ion batteries. During Li- and Na-insertion, the Sb 2 Se 3 and a –Sb 2 Se 3 /C electrodes are converted into the final phases of Li 3 Sb/Na 3 Sb and Li 2 Se/Na 2 Se, respectively. During Li- and Na-extraction, the Li 3 Sb/Na 3 Sb and Li 2 Se/Na 2 Se in the Sb 2 Se 3 electrode are converted into Sb and Se, showing a non-recovery reaction, whereas a recovery to the original Sb 2 Se 3 in the a –Sb 2 Se 3 /C electrode occurs after full Li and Na extraction. Owing to the interesting conversion/recovery reaction, the a –Sb 2 Se 3 /C electrode exhibits excellent electrochemical performance, such as high reversible capacities (Li-ion battery: 662 mAh g−1; Na-ion battery: 407 mAh g−1), a long cycle life with highly reversible capacities (Li-ion battery: 662 mAh g−1 and 1,205 mAh cm−3, respectively, after 100th cycle; Na-ion battery: 378 mAh g−1 and 688 mAh cm−3, respectively, after 50th cycle), and high rate capabilities (Li-ion battery: 623 mAh g−1 and 1,133 mAh cm−3 at 3C; Na-ion battery: 270 mAh g−1 and 492 mAh cm−3 at 2C). Image 1 • A layered Sb 2 Se 3 and its amorphous Sb 2 Se 3 /C composite is synthesized simply. • The reaction mechanisms during Li- and Na-insertion/extraction is demonstrated. • The Sb 2 Se 3 had conversion/non-recovery reactions during Li- and Na-reactions. • The Sb 2 Se 3 /C had conversion/full-recovery reactions during Li- and Na-reactions. • The amorphous Sb 2 Se 3 /C exhibited excellent electrochemical performances. [ABSTRACT FROM AUTHOR]

Herein, we describe a simple solid-state synthesis of zinc sulfide (ZnS) and its amorphous carbon–modified nanocomposite (ZnS/C) and examine their performance as high-capacity anode materials for rechargeable Li-ion batteries, probing lithiation/delithiation mechanisms by ex situ X-ray diffraction and extended X-ray absorption fine structure analyses. The ZnS converted into LiZn and Li 2 S during lithiation, being subsequently incompletely recombined into ZnS during delithiation and thus resulting in traces of Zn and S. Based on the above investigation of reaction mechanism, the ZnS/C electrode was electrochemically tested within a potential range of 0–2.0 V vs. Li + /Li and exhibited a high reversible capacity of 681 mAh g −1 , excellent cycling stability (>150 cycles), and high rate capability. [ABSTRACT FROM AUTHOR]

Abstract: A Sn–Co–C composite is prepared by mechanochemical synthesis using tin powder and a cobalt–carbon composite through the pyrolysis of Co (III)-acetylacetonate. The composite is studied as an anode material for Li secondary batteries. The reaction mechanism is investigated using various analytical techniques. Although the composite is initially composed of Co3Sn2 as the major phase and CoSn2 as the minor one, the Co3Sn2 transformed into CoSn2 during the second cycle and remained in this form throughout the following cycles. The Sn–Co–C composite shows an excellent capacity retention of 435mAhg−1 over 100 cycles. [Copyright &y& Elsevier]

[Display omitted] • A new synthesis method of black P-based composites is developed. • The composites are composed of nanocrystalline black P within the metal oxide matrices. • The composites are investigated as anode materials in rechargeable Li-ion batteries. • Black P@TiO 2 exhibited excellent electrochemical performance. A simple, inexpensive, and scalable method for transforming phosphorous pentoxide (P 2 O 5) into black phosphorus (BP)-based composites was developed. The BP-based composites of BP@MgO, BP@Al 2 O 3 , and BP@TiO 2 synthesized by a one-pot mechanochemical reduction of P 2 O 5 using Mg, Al, or Ti were composed of nanocrystalline BP within the metal oxide matrices of MgO, Al 2 O 3 , or TiO 2 , respectively. Subsequently, the potential of these composites as anode materials in rechargeable Li-ion batteries (LIBs) was investigated. BP@TiO 2 showed the highest electrochemical performance among the BP-based composites. Specifically, the BP@TiO 2 exhibited a high reversible capacity over 510 mAh g−1 after 300 cycles and a fast rate capability of ~ 400 mAh g−1 at the 3C rate. The superior electrochemical performance of BP@TiO 2 was attributed to the well-dispersed nanocrystalline BP and the Li-reactive TiO 2 matrix. Additionally, the formation of Li x TiO 2 in the Li-reactive TiO 2 matrix during Li cycling increased the electrochemical Li-ion conductivity and diffusivity, contributing to the enhanced electrochemical performance. Therefore, the BP@TiO 2 synthesized by the one-pot mechanochemical reduction has high potential as a superior LIB anode. [ABSTRACT FROM AUTHOR]

• Monoclinic VP 2 synthesized and tested as LIB anodes. • VP 2 undergoes topotactic/conversion and recombination during Li-insertion and extraction. • VP 2 shows high electrochemical performance in topotactic reaction potential region. • Graphite-modified composite VP 2 @G shows excellent Li storage performance. Vanadium diphosphide (VP 2) and its graphite-modified composite (VP 2 @G) were fabricated using a fast and simple solid-state manner, and evaluated as Li-ion battery (LIB) anodes. The electrochemical Li-mechanism of VP 2 was investigated using various ex situ tools. During Li-insertion, VP 2 underwent a topotactic-reaction by the formation of Li x VP 2 (x ≤ 1.5), and then was converted to Li 3 P and V phases with a partially unconverted Li x VP 2 phase at the Li-inserted state of 0 V via a partial conversion reaction. Conversely, during Li-extraction, Li 3 P, V, and unconverted Li x VP 2 phases recombined fully into VP 2. First, when VP 2 was used the topotactic-reaction between Li x VP 2 and VP 2 (potential region: 0.3–2.0 V), stable cycling performance with a high volumetric-capacity (595 mAh cm–3 after 100 cycles) and fast rate performance (~555 mAh cm–3 at 2 C and ~530 mAh cm–3 at 3 C) were attained. Additionally, the graphite-modified composite VP 2 @G (potential region: 0–2.0 V) also exhibited stable cycling performance with a high gravimetric-capacity (602 mAh g−1 after 100 cycles) and fast rate performance (~530 mAh g−1 at 1 C and ~470 mAh g−1 at 2 C), which was attributed to the well-dispersed nanocrystalline (~10–20 nm) VP 2 in the Li-buffering graphite matrix. Therefore, the VP 2 and VP 2 @G have high potential as a superior LIB anode. [ABSTRACT FROM AUTHOR]

Rechargeable K-ion batteries (KIBs) have attracted tremendous attention as a replacement for Li-ion batteries because potassium is earth-abundant and inexpensive. Although the formation of K-ion intercalated graphite compounds gives graphite a reasonable capacity, its capacity is insufficient, and its initial Coulombic efficiency (ICE) is low because of the slow kinetics of the large K ion. In this study, to address the shortcomings of graphite anodes for KIBs, we obtained a high-performance C-based anode by a simple, scalable two-step approach of amorphization and prepotassiation of carbon black (CB). CB was amorphized to provide numerous K-ion insertion sites and thus improve the K storage properties. However, the ICE and reversible capacity (RC) remained low. Therefore, to enhance the electrochemical performance, the amorphized CB (a-CB) was prepotassiated. The prepotassiated/amorphized CB showed a high RC (>300 mAh g−1) with an extraordinarily high ICE (>100%), high rate capability (255 mAh g−1 at 1C, 210 mAh g−1 at 2C), and remarkable cycling stability after 300 cycles at a high rate of 1C. Its electrochemical performance is among the best reported for C-based anode materials for KIBs, which suggests that it is a promising material for next-generation KIB anodes. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanocrystalline Ge exhibited higher Li reversibility than bulk Ge. • Li reaction pathways in nanocrystalline Ge were definitively established. • Ge/Al 2 O 3 /C was synthesized by one-pot mechanical solid-state reduction. • Ge/Al 2 O 3 /C exhibited good cyclic behavior, rate capability, and reversible capacity. Ge is a highly researched anode material for Li-ion batteries (LIBs) owing to its high theoretical Li storage capacity and higher electrical conductivity compared to that of Si. However, Li reaction pathways in Ge have not been definitively established due to the formation of various and complicated Li-Ge alloy phases during lithiation/delithiation. Evaluation of the Li storage characteristics of bulk and nanocrystalline Ge demonstrated that nanocrystalline Ge showed higher Li reversibility than bulk Ge. Various cutting-edge ex situ techniques were used to analyze nanocrystalline Ge, and the Li reaction pathways in Ge were thoroughly demonstrated. To enhance the electrochemical Li storage characteristics of Ge, a Ge-based nanocomposite, Ge/Al 2 O 3 /C, was synthesized via simple one-pot mechanical solid-state reduction using GeO 2 , Al, and C. Ge/Al 2 O 3 /C exhibited very stable cyclic behavior at a current density of 100 mA g−1 over 300 cycles (capacity retention after 300 cycles: ∼95 %). Moreover, Ge/Al 2 O 3 /C exhibited excellent rate capability with high reversible capacity and stable cyclic behavior at a high 1C-rate. The superior electrochemical performance of Ge/Al 2 O 3 /C was attributed to the nanoscale dimensions of Li-active nanocrystalline Ge (∼10 nm) and Li-inactive Al 2 O 3 (∼12 nm) embedded uniformly in the amorphous carbon matrices. The size of nanocrystalline Ge in nanocomposite was consistently maintained during repeated cycles owing to the anti-agglomeration effect of the uniformly distributed Li-inactive Al 2 O 3 and amorphous carbon matrices. We anticipate that the electrochemical Li reaction pathways in Ge and the resulting high-performance nanocomposite anodes will be highly useful in investigating high-performance Ge-based anodes for LIBs. [ABSTRACT FROM AUTHOR]

Sodium-ion battery is being regraded as an alternative to lithium-ion batteries in view of low-cost and high energy density. However, poor cycle life accompanying huge electrode swelling of existing metal based anode are the main issues to be solved. Sb 2 S 3 embedded in amorphous phosphorus/carbon matrix is synthesized from P 2 S 5 , Sb, and carbon by using a facile mechano-chemical method and subsequent heat treatment, which is investigated on its potential as anode material for rechargeable sodium ion batteries. Several analytical tools including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron spectroscopy (TEM) reveal that as-synthesized composite is composed of Sb 2 S 3 nano-crystallites (less than 10 nm) dispersed in robust phosphorus/carbon (P/C) composite matrix. Although Sb 2 S 3 nano-domain converts to the Sb and S during sodiation, the recombination of Sb and S to form the original Sb 2 S 3 phase is also confirmed by HR-TEM image of the subsequently desodiated electrode. This composite electrode exhibits superior electrochemical performances including a high reversible capacity of 654 mAh g −1 with well controlled electrode swelling of 62% at fully charged state, an excellent cycle stability with a capacity retention of 93.4% after 100th cycle at 50 mA g −1 for sodium ion batteries. Furthermore, even at a high current density of 2000 mA g −1 (3C rate), a desodiation capacity of 390 mAh g −1 is achieved. These outstanding electrochemical performances are attributed to the effective mechanical-buffering and electrical-conduction properties of the amorphous P/C composite matrix, which also prevent the aggregation of electroactive particles reacting with Na. [ABSTRACT FROM AUTHOR]

Amorphous ZnSb/MgO/C (I) and ZnSb/Al2O3/C (II) nanocomposite anodes are prepared via high-energy ball milling of ZnO and Sb2O3, Mg or Al, and C in molar ratios of 2:1:5 and 6:3:10 under Ar, respectively. [ABSTRACT FROM AUTHOR]

Robust hierarchical nanocube framework CoS 2 -based composites comprising of nanocrystalline CoS 2 (∼8–10 nm) encapsulated in a robust carbon-core matrix entangled in carbon nanotubes (CNTs) were synthesized, and their performance as electrodes for Li-ion batteries (LIBs) and Na-ion batteries (NIBs) was evaluated. The robust nanocube framework CoS 2 -C-CNT composites were synthesized from Co-based metal-organic frameworks by an efficient two-step synthesis process of carbonization and sulfidation. The structural phase change mechanism of CoS 2 was systematically characterized by ex situ analysis tools, which revealed that it involved a conversion during Li/Na-insertion and a recombination reaction during Li/Na-extraction. The unique structural characteristics of the nanocube framework CoS 2 -C-CNT composites and the unique structural phase change mechanism of CoS 2 are attributed to the superior Li/Na-storage performances. The nanocube framework CoS 2 -C-CNT composites delivered a large reversible capacity (LIB: 770 mAh g−1 and NIB: 629 mAh g−1), excellent cycling (LIB: 726 mAh g−1 after 250 cycles and NIB: 531 mAh g−1 after 100 cycles), and fast rate behavior (LIB: 613 mAh g−1 at 3C and NIB: 391 mAh g−1 at 2C rates). This remarkable robust nanocube framework composite structure is highly applicable to various LIB/NIB electrode materials owing to their excellent Li/Na-ion storage characteristics. [Display omitted] • Nanocube framework CoS 2 -based composite is synthesized by efficient two step method. • Li- and Na-reaction mechanism of CoS 2 anode is fully demonstrated. • The robust nature of nanocube framework CoS 2 -C-CNT is demonstrated by ex situ TEM. • Nanocube framework CoS 2 -C-CNT exhibits excellent Li- and Na-storage performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A superior carbon black as conducting additive and LIB and NIB anodes is developed. • The superior carbon black is synthesized by amorphization and pre-lithiation/sodiation. • Electrochemical mechanism of the superior carbon black is elucidated using various analytical techniques. • The superior carbon black compensates ICE and increases the reversible capacity of anode materials. Carbon black (CB) is an inexpensive and widely used carbonaceous material. However, the reversibility between CB and Li or Na is very poor, and the initial coulombic efficiency (ICE) is so low that it cannot be used as an electrode material for rechargeable batteries. In this study, we successfully designed superior CB as a high-performance conducting additive for Li-ion batteries (LIBs) and Na-ion batteries (NIBs) using a simple two-step strategy: amorphization and pre-lithiation/sodiation. The Li- and Na-reversible capacities of amorphized CB increased significantly from 213 to 564 mAh g−1 for LIB and from 92 to 209 mAh g−1 for NIB; however, the corresponding ICEs of 61.5% for LIB and 33.5% for NIB are poor. The poor ICEs are supplemented via pre-lithiation/sodiation in the amorphized CB, which show over 100% ICEs with high Li- and Na-reversible capacities. Specifically, the modified CB has highly reversible capacities (>500 mAh g−1 for LIB, >300 mAh g−1 for NIB) with exceptionally high ICEs (133% ICE for LIB, 160% ICE for NIB), stable reversible capacities for over 100 cycles (470 mAh g−1 for LIB, 278 mAh g−1 for NIB), fast rate capabilities with highly reversible capacities at a 3C rate (~330 mAh g−1 for LIB, ~190 mAh g−1 for NIB), and excellent cycling behavior for over 300 cycles at a 1C rate. When used as a conducting additive, this CB contributes to high electrical conductivity and increase of ICE and the reversible capacity for LIB and NIB anode materials. These results are expected to have a significant impact on LIBs and NIBs. [ABSTRACT FROM AUTHOR]

• A Si-based composite interconnected by multiple matrices is developed. • The Si-based composite is fabricated by a combination of two simple solid-state methods. • The Si-based composite contains Si, a Li-inactive Cu 3 Si, and multiple carbon-based matrices. • The Si-based composite exhibits excellent electrochemical performances. To obtain anode materials with high performance Li-ion batteries, a nanostructured Si-based composite, including Si, a Li-inactive conducting Cu 3 Si matrix, and multiple carbon-based matrices (carbon nanotube, graphite, and a pyrolytic carbon coating) is developed by facile step-by-step combination of solid-state synthetic technologies. First, various Si x Cu y alloys with different weight compositions are synthesized by a simple ball-milling process. Among the Si x Cu y alloys, Si 80 Cu 20 , which is comprised of Si and Cu 3 Si, displays the highest electrochemical performance. To further improve the electrochemical performance of Si-Cu 3 Si, an interconnected composite with 1D-structured CNT and 3D-structured graphite, Si-Cu 3 Si-CNT/G, is prepared via an additional ball-milling process. The Si-Cu 3 Si-CNT/G composite is finally coated via the pyrolysis of polyvinyl chloride, thus forming the carbon-coated Si-Cu 3 Si-CNT/G-C composite. This final product, Si-Cu 3 Si-CNT/G-C, is comprised of well-dispersed nanocrystalline Si and Cu 3 Si (Li-inactive conducting matrix) within the multiple interconnected carbon matrices. The Si-Cu 3 Si-CNT/G-C displays excellent electrochemical performance, with a high first reversible capacity of 1237 mA h g−1, a high initial coulombic efficiency of 82.8%, a long cycle durability of 1084 mAh g−1 over 100 cycles, and a high rate capability of ~1000 mAh g−1 at 1C-rate, which confirms its commercial application as a high-performance Si-based anode for Li-ion batteries. [ABSTRACT FROM AUTHOR]