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Through alteration of the polarity of DC plasma during the growth of carbon nanotubes in a PECVD reactor, significantly different morphologies of such species have been achieved. By using this approach, for the first time, both Half‐aligned and Entangled structures were synthesized, along with Full‐aligned carbon nanotubes, introducing three binder‐free electrodes with various levels of tortuosity. The crucial parameter and influential effect of tortuosity in these three‐dimensional nanostructure scaffolds for application in lithium‐ion batteries were investigated. Previous research findings suggested that increasing the tortuosity of the conductive scaffolds leads to preferential accumulation of lithium at the top surface and causes the loss of capacity in subsequent charge‐discharge cycles. Our finding reveals that there exists a trade‐off between lithium‐demand, capacity, and preferential accumulation of lithium at the top surface. Among the presented scaffolds, the Half‐aligned MWCNTs was able to maintain a high capacity of 876.9 mAh/g over more than 300 cycles, and demonstrate capacity improvement during this period and excellent rate capability, even at a rate of 5 C. This capacity is almost three times that can be achieved with graphite, showcasing promising and outstanding results for carbon nanotubes. [ABSTRACT FROM AUTHOR]

In this study, synthesis of TiS2 nanoflakes is reported using a home-made CVD furnace. With vaporing sulfur powder in this system, TiS2 nanosheets were grown directly on the Ti powder. The application of these nanoflakes as a possible cathode material for sodium-ion battery has also been investigated. The prepared nanosheets were formed in highly packed clusters with a typical width of around 30 nm and height of 2 µm. The interlayer space between the nanoflakes can provide facile access path for intercalation of sodium ions. The synthesized TiS2 nanoflakes have been implemented for the fabrication of sodium-ion battery cathode electrode, using a 8:1:1 weight ratio of active material:C65: PVDF for slurry preparation, followed by coating on an aluminum current collector. The prepared electrode exhibits an initial reversible capacity (2nd cycle) of 114 mAh g−1 at current density of 66.7 mAg−1. It also showed remarkable coulombic efficiency of 99% after 100 cycles. It also showed superb cycling stability by only 7% decay after 100 cycles. These nanosheets are proposed as a high-performance cathode material for sodium-ion battery. [ABSTRACT FROM AUTHOR]

The NASICON-type lithium aluminum titanium phosphate (LATP) solid-state electrolyte is considered as a promising candidate for next-generation lithium metal batteries with high energy density. However, the instability of LATP in the presence of Li metal and its poor contact with the electrodes hinder its practical application. Here, a novel protective-layer (PL) consisting of a PVDF-HFP polymer matrix and LiF ceramic particles was developed. The proposed layer provides a suitable interface between LATP and the electrodes, prevents the reduction of LATP by Li metal, and suppresses the growth of Li dendrites. The excellent performance of the PL‖LATP‖PL structure as a ceramic-polymer composite electrolyte (CPCE) was demonstrated by Li‖CPCE‖Li symmetric cell plating/stripping for 1000 hours at 0.5 mA cm−2 without a short circuit. In addition, the assembled LiFePO4‖CPCE‖Li full-cell was tested at two different C-rates of 0.2C and 1C. The cell cycled at 0.2C was durable and stable for about eight months and retained 86.4% of the initial capacity of 135.6 mA h g−1, while the other cell cycled at 1C had desirable cycling performance for 2000 cycles with little capacity degradation of about 12.5%. In this study, an efficient and robust composite electrolyte was proposed for the development of solid-state Li-metal batteries with high stability, long lifetime, and high power density. [ABSTRACT FROM AUTHOR]

This study has investigated the effect of carbon coating on the electrochemical performance of SnO2 Nanowires (NWs) as an electrode along with a bis (trifluoromethane) sulfonimide lithium (LiTFSI)-based electrolyte in a lithium-ion battery (LIB). The vaporâ€"liquidâ€"solid approach has been used to grow SnO2 NWs on the stainless steel mesh current collector. The obtained results have demonstrated that the utilization of the LiTFSI-based electrolyte improved the battery performance with the SnO2 NWs electrode over the LiPF6-based electrolyte. This may be due to the formation of a stable and thin solid electrolyte interphase layer. Since bare SnO2 NWs exhibit inferior cycling stability due to their high volumetric expansion and poor conductivity, incorporating carbon coating could improve performance. Although the initial discharge specific capacity obtained for the carbon-coated SnO2 NWs (SnO2 NWs@C) electrode (1328.4 mAh gâˆ'1) was in the order of the first discharge capacity for the SnO2 NWs, the SnO2 NWs@C electrode possessed capacity retention with six times improvement as compared to the pristine SnO2 NWs after 120 cycles. The Coulombic efficiency of 99% has been achieved for the SnO2 NWs@C electrode over 120 cycles. Field emission scanning electron microscopy images revealed that the carbon coating could keep the overall structure of the electrode upon cycling. It has been evidenced that the SnO2 NWs@C electrode with LiTFSI-based electrolyte has an excellent potential to implement in high-performance LIBs. [ABSTRACT FROM AUTHOR]

SnO2 is considered as one of the high specific capacity anode materials for Lithium-ion batteries. However, the low electrical conductivity of SnO2 limits its applications. This manuscript reports a simple and efficient approach for the synthesis of Sb-doped SnO2 nanowires (NWs) core and carbon shell structure which effectively enhances the electrical conductivity and electrochemical performance of SnO2 nanostructures. Sb doping was performed during the vapor-liquid-solid synthesis of SnO2 NWs in a horizontal furnace. Subsequently, carbon nanolayer was coated on the NWs using the DC Plasma Enhanced Chemical Vapor Deposition approach. The carbon-coated shell improves the Solid-Electrolyte Interphase stability and alleviates the volume expansion of the anode electrode during charging and discharging. The Sb-doped SnO2 core carbon shell anode showed the superior specific capacity of 585 mAhg−1 after 100 cycles at the current density of 100 mA g−1, compared to the pure SnO2 NWs electrode. The cycle stability evaluation revealed that the discharge capacity of pure SnO2 NWs and Sb doped SnO2 NWs electrodes were dropped to 52 and 152 mAh g−1 after100th cycles. The process of Sb doping and carbon nano shielding of SnO2 nanostructures is proposed for noticeable improvement of the anode performance for SnO2 based materials. [ABSTRACT FROM AUTHOR]

By using silicon (Si) as an anode of lithium-ion batteries, the capacity can be significantly increased, but relatively large volume expansion limits the application as an efficient anode material. Huge volume expansion of the silicon anode during lithiation, however, leads to cracking and losing its connection with the current collector. This shortcoming can be improved by the deposition of a nanometric carbon- or nitrogen-doped carbon coating on the silicon surface, resulting in Si/C-layer and Si/C 3 N 4 interfaces. In this work, Li + diffusion in Si/C-layer and Si/C 3 N 4 composite materials along three Si surfaces and various ion pathways were carefully analyzed by using density functional theory and ab initio molecular dynamic (AIMD) simulations. Both Si/C and Si/C 3 N 4 interfaces and three Si surfaces of (100), (110), and (111) were investigated. The formation of nitrogen holes and monatomic carbon binders in the composite increases ion diffusivity and limits volume expansion. Furthermore, the Bader analysis shows that the type and orientation of the surfaces have important effects on ion distribution. The results indicated that the C 3 N 4 composite increases Li + diffusion in Si (100) from 7.82 × 10 -5 to 3.17 × 10 -4 cm 2 /s. The presented results provide a guide for the appropriate design of stable and safe high-energy-density batteries., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

SnO 2 is considered as one of the high specific capacity anode materials for Lithium-ion batteries. However, the low electrical conductivity of SnO 2 limits its applications. This manuscript reports a simple and efficient approach for the synthesis of Sb-doped SnO 2 nanowires (NWs) core and carbon shell structure which effectively enhances the electrical conductivity and electrochemical performance of SnO 2 nanostructures. Sb doping was performed during the vapor-liquid-solid synthesis of SnO 2 NWs in a horizontal furnace. Subsequently, carbon nanolayer was coated on the NWs using the DC Plasma Enhanced Chemical Vapor Deposition approach. The carbon-coated shell improves the Solid-Electrolyte Interphase stability and alleviates the volume expansion of the anode electrode during charging and discharging. The Sb-doped SnO 2 core carbon shell anode showed the superior specific capacity of 585 mAhg -1 after 100 cycles at the current density of 100 mA g -1 , compared to the pure SnO 2 NWs electrode. The cycle stability evaluation revealed that the discharge capacity of pure SnO 2 NWs and Sb doped SnO 2 NWs electrodes were dropped to 52 and 152 mAh g -1 after100th cycles. The process of Sb doping and carbon nano shielding of SnO 2 nanostructures is proposed for noticeable improvement of the anode performance for SnO 2 based materials., (© 2021 IOP Publishing Ltd.)

Here, we report 3D hierarchical SnO 2 nanowire (NW) core-amorphous silicon shell on free-standing carbon nanotube paper (SnO 2 @a-Si/CNT paper) as an effective anode for flexible lithium-ion battery (LIB) application. This binder-free electrode exhibits a high initial discharge capacity of 3020 mAh g -1 with a large reversible charge capacity of 1250 mAh g -1 at a current density of 250 mA g -1 . Compared to other SnO 2 NW or its core-shell nanostructured anodes, the fabricated SnO 2 @a-Si/CNT structure demonstrates an outstanding performance with high mass loading (∼5.9 mg cm -2 ), high areal capacity (∼5.2 mAh cm -2 ), and large volumetric capacity (∼1750 mAh cm -3 ) after 25 cycles. Due to the incorporation of CNT paper as the current collector, the weight and thickness of the total electrode is effectively reduced with respect to the conventional LIB anodes. The fabricated electrode has a total thickness of only 30 μm and considering the total weight of the electrode (active mass + current collector), an initial discharge/charge capacity of 2460/1018 mAh g -1 is obtained. Hence, this thin, lightweight and highly flexible structure is proposed as an excellent candidate for high-performance LIB anode materials, especially in flexible electronics.