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• The ant's nest-like Si/C composite anode enhances cyclic stability in micron-sized Si/C composites under high mass loading. • Different carbon materials significantly affect the independent charge–discharge behavior of Si within Si/C composites. • In-situ XRD reveals transitions of Si between crystalline and amorphous states during charge/discharge in Si/C anodes. • The use of hard carbon in Si/C composite anodes leads to improved conversion depth of amorphous Si-Li alloys. Due to the demand for high mass loading in industrial application, micron-sized Si/C composites are preferred compared to nanoparticles. Utilizing Al-Si alloy as the raw material, an ant's nest-like porous Si/C composite material was successfully constructed through carbon coating and acid etching techniques, leading to an improvement in the cyclic stability of micron-sized Si/C composites under high mass loading. Furthermore, notable observations were made regarding the influence of carbon material type on the independent charge–discharge behavior of Si within the Si/C composite material, especially during the plateau region of Si-Li conversion processes. In-situ XRD test revealed transitions of Si between crystalline and amorphous states in the Si/C composite material during charge and discharge processes. Additionally, in Si/C composite materials fabricated using hard carbon, the increased lithium-ion transport rate attributed to the highly disordered structure of hard carbon promotes the acquisition of charges during delithiation process. As a result, this decelerates the lithium de-alloying process in Si-Li alloys, leading to an improved conversion depth of amorphous Si-Li alloys and a reduction in electrode capacity decay. This study provides valuable insights into Si conversion processes within Si/C composite materials and offers rational strategies for future material optimization. [ABSTRACT FROM AUTHOR]

As a class of redox active materials with some preferable properties, including rigid structure, insoluble characters, and large amounts of nitrogen atoms, covalent triazine frameworks (CTFs) have been frequently adopted as electrode materials in Lithium-ion batteries (LIBs). Herein, a triazine-based covalent organic framework employing 3,4-ethylenedioxythiophene (EDOT) as the bridging unit is synthesized by the presence of carbon powder through Stille coupling reaction. The carbon powder was added in an in-situ manner to overcome the low intrinsic conductivity of the polymer, which led to the formation of the polymer@C composite (PTT-O@C, PTT-O is a type of CTFs). The composite material is then employed in LIBs as anode material. The designed polymer shows a narrow band gap of 1.84 eV, proving the effectiveness of the nitrogen-enriched triazine unit in reducing the band gap of the resultant polymers. The CV results showed that the redox potential of the composite (vs. Li/Li+) is around 1.0 V, which makes it suitable to be used as the anode material in lithium-ion batteries. The composite material could exhibit the stable specific capacity of 645 mAh/g at 100 mA/g and 435 mAh/g at 500 mA/g, respectively, much higher than the pure carbon materials, indicating the good reversibility of the material. This work provides some additional information on electrochemical performance of the triazine and EDOT based CTFs, which is helpful for developing a deep understanding of the structure–performance correlations of the CTFs as anode materials. [ABSTRACT FROM AUTHOR]

Extraordinarily high reversible capacity of lithium-ion battery anodes is realized from SnO2/α-MoO3core-shell nanobelts. The reversible capacity is much higher than traditional theoretical results. Such behavior is attributed to α-MoO3that makes extra Li2O reversibly convert to Li+. [ABSTRACT FROM AUTHOR]

α-MoO 3 @MnO 2 core-shell nanorods are synthesized via a facile two-step method. The electrochemical measurement of lithium-ion batteries (LIBs) shows that prepared α-MoO 3 @MnO 2 core-shell nanorods as the anode exhibit high discharge capacity, high rate capability, and excellent cycling stability. The reversible capacity of α-MoO 3 @MnO 2 core-shell nanorods is 1475 mAh/g at 0.1 C rate (10 hours per charging cycle) and retains at 1127 mAh/g after 50 cycles, much higher than that of pure α-MoO 3 and MnO 2 . Even at high current rate of 6 C, the reversible capacity of α-MoO 3 @MnO 2 core-shell nanorods is 394 mAh/g and retains at 286 mAh/g after 50 cycles. Our results indicate that α-MoO 3 @MnO 2 core-shell nanocomposites have enormous potential for application in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: Core–shell SnO2@TiO2–B nanowires are synthesized via a two-step hydrothermal route. SnO2 nanoparticles are uniformly coated on the whole surface of TiO2–B nanowires. As the anode of lithium ion batteries, core–shell SnO2@TiO2–B nanowires exhibit high lithium storage capacity and superior rate capability. The reversible capacity is ~1160mAhg−1 at C/5 rate (5h per charging cycle) and the retention is 790mAhg−1 after 30 cycles. At the rate of 2C, the capacity can be maintained at 556mAhg−1. Such a good lithium storage performance can be attributed to the synergistic effect between SnO2 and TiO2–B nanostructures. [Copyright &y& Elsevier]

Abstract: SnS2–graphene nanocomposites are synthesized by a hydrothermal method, and their application as anodes of lithium-ion batteries has been investigated. SnS2 nanosheets are uniformly coating on the surface of graphene. SnS2–graphene nanocomposites exhibit high cyclability and capacity. The reversible capacity is 766 mAh/g at 0.2C rate and maintains at 570 mAh/g after 30 cycles. Such a high performance can be attributed to high electron and Li-ion conductivity, large surface area, good mechanical flexibility of graphene nanosheets and the synergetic effect between graphene and SnS2 nanostructures. The present results indicate that SnS2–graphene nanocomposites have potential applications in lithium-ion battery anodes. [Copyright &y& Elsevier]

Abstract: SnO2–MnO2–SnO2 sandwich-structured nanotubes are synthesized by uniformly coating SnO2 nanoparticles on both the inner and outer walls of α-MnO2 nanotubes via a simple wet-chemical route. As the anodes of lithium ion batteries, SnO2–MnO2–SnO2 sandwich-structured nanotubes exhibit high reversible capacity, cyclability and rate capability. The reversible capacity of the nanocomposites is 847.5mAh/g and retains 716.0mAh/g after 50 cycles, which is higher than that of α-MnO2 or SnO2. At 20C rate, SnO2–MnO2–SnO2 sandwich-structured nanotubes can deliver a capacity of 224.2mAh/g. Such excellent performances can be attributed to the synergistic effect and the tubular nanostructures. Our results imply that one-dimensional sandwich-structured nanocomposites have potential applications in lithium ion batteries. [Copyright &y& Elsevier]

Abstract: SnO2/NiO core-shell nanobelts have been synthesized simply by coating NiO nanobelts with a thin layer of SnO2 nanoparticles. As the anode material of lithium-ion battery, SnO2/NiO core-shell nanobelts exhibit higher reversible capacity (∼900mAh/g at C/20 rate) and better cycling performance than individual NiO or SnO2 materials. The excellent performance can be attributed to the synergistic effect between SnO2 and NiO. Our results demonstrate the potential applications of SnO2/NiO core-shell nanobelts in high-performance lithium-ion batteries. [Copyright &y& Elsevier]

Abstract: Hybrid SnO2/nanocarbon families (graphene nanosheets (GNSs), single-wall carbon nanotubes (SWCNTs), multi-wall carbon nanotubes (MWCNTs) and carbon nanospheres (CNSs)) have been synthesized by a similar wet chemical method. SnO2 nanoparticles are uniformly loaded on the surface of the nanocarbon families. As lithium battery anodes, their electrochemical properties of the reaction of lithium are investigated under the same conditions. To compare between them, SnO2/GNSs have the largest capacity; SnO2/GNSs and SnO2/SWCNTs have high cyclability; and SnO2/MWCNTs can maintain the capacity at high current density. Such behaviors are ascribed to their surface-to-volume ratio, structure flexibility, ion mobility and electron conductivity. The present results are the bases for their practical applications in lithium-ion battery anodes. [Copyright &y& Elsevier]

Abstract: NiO nanowalls/graphene nanosheets (NiO/GNSs) nanocomposites are synthesized by a hydrothermal method, and their application as anodes of lithium-ion batteries has been investigated. NiO nanowalls were uniformly coated over the surface of graphene. NiO/GNSs nanocomposites exhibit extremely high cyclability and capacity. The reversible capacity is 844.9mAhg−1 at 0.1C rate (10h per half cycle) and fades merely 7.1% after 50 cycles. The present results indicate that NiO/GNS nanocomposites have potential applications in lithium-ion battery anodes. [Copyright &y& Elsevier]

Abstract: Co3O4/graphene nanocomposites are synthesized by a hydrothermal method, and their extremely high capacity and stability as the anode of lithium-ion battery is obtained. Co3O4 nanowires with the length of ~500nm and the diameter of ~50nm are uniformly coated on the surface of graphene nanosheets. The reversible capacity is 906.6mAhg−1 at 0.1C rate (10h per charging cycle) and fades merely 6.9% after 50 cycles. Such behaviors can be attributed to high electron and Li-ion conductivity, large surface area, good mechanical flexibility of graphene nanosheets and the synergetic effect between graphene and Co3O4 nanostructures. The present results indicate that Co3O4/graphene nanocomposites have potential applications in the anode of LIB. [Copyright &y& Elsevier]