Hydrothermal synthesis of carbon nanotube/cobalt oxide core-shell one-dimensional nanocomposite and application as an anode material for lithium-ion batteries

A Review on Recent Advancements of Ni-NiO Nanocomposite as an Anode for High-Performance Lithium-Ion Battery

Recently, lithium-ion batteries (LIBs) have been widely employed in automobiles, mining operations, space applications, marine vessels and submarines, and defense or military applications. As an anode, commercial carbon or carbon-based materials have some critical issues such as insufficient charge capacity and power density, low working voltage, deadweight formation, short-circuiting tendency initiated from dendrite formation, device warming up, etc., which have led to a search for carbon alternatives. Transition metal oxides (TMOs) such as NiO as an anode can be used as a substitute for carbon material. However, NiO has some limitations such as low coulombic efficiency, low cycle stability, and poor ionic conductivity. These limitations can be overcome through the use of different nanostructures. This present study reviews the integration of the electrochemical performance of binder involved nanocomposite of NiO as an anode of a LIB. This review article aims to epitomize the synthesis and characterization parameters such as specific discharge/charge capacity, cycle stability, rate performance, and cycle ability of a nanocomposite anode. An overview of possible future advances in NiO nanocomposites is also proposed.

Carbon Nanotubes-Based Nanomaterials and Their Agricultural and Biotechnological Applications

Carbon nanotubes (CNTs) are considered a promising nanomaterial for diverse applications owing to their attractive physicochemical properties such as high surface area, superior mechanical and thermal strength, electrochemical activity, and so on. Different techniques like arc discharge, laser vaporization, chemical vapor deposition (CVD), and vapor phase growth are explored for the synthesis of CNTs. Each technique has advantages and disadvantages. The physicochemical properties of the synthesized CNTs are profoundly affected by the techniques used in the synthesis process. Here, we briefly described the standard methods applied in the synthesis of CNTs and their use in the agricultural and biotechnological fields. Notably, better seed germination or plant growth was noted in the presence of CNTs than the control. However, the exact mechanism of action is still unclear. Significant improvements in the electrochemical performances have been observed in CNTs-doped electrodes than those of pure. CNTs or their derivatives are also utilized in wastewater treatment. The high surface area and the presence of different functional groups in the functionalized CNTs facilitate the better adsorption of toxic metal ions or other chemical moieties. CNTs or their derivatives can be applied for the storage of hydrogen as an energy source. It has been observed that the temperature widely influences the hydrogen storage ability of CNTs. This review paper highlighted some recent development on electrochemical platforms over single-walled CNTs (SWCNTs), multi-walled CNTs (MWCNTs), and nanocomposites as a promising biomaterial in the field of agriculture and biotechnology. It is possible to tune the properties of carbon-based nanomaterials by functionalization of their structure to use as an engineering toolkit for different applications, including agricultural and biotechnological fields.

Insights into Metal Oxide and Zero-Valent Metal Nanocrystal Formation on Multiwalled Carbon Nanotube Surfaces during Sol-Gel Process

Carbon nanotubes are hybridized with metal crystals to impart multifunctionality into the nanohybrids (NHs). Simple but effective synthesis techniques are desired to form both zero-valent and oxides of different metal species on carbon nanotube surfaces. Sol-gel technique brings in significant advantages and is a viable technique for such synthesis. This study probes the efficacy of sol-gel process and aims to identify underlying mechanisms of crystal formation. Standard electron potential (SEP) is used as a guiding parameter to choose the metal species; i.e., highly negative SEP (e.g., Zn) with oxide crystal tendency, highly positive SEP (e.g., Ag) with zero-valent crystal-tendency, and intermediate range SEP (e.g., Cu) to probe the oxidation tendency in crystal formation are chosen. Transmission electron microscopy and X-ray diffraction are used to evaluate the synthesized NHs. Results indicate that SEP can be a reliable guide for the resulting crystalline phase of a certain metal species, particularly when the magnitude of this parameter is relatively high. However, for intermediate range SEP-metals, mix phase crystals can be expected. For example, Cu will form Cu₂O and zero-valent Cu crystals, unless the synthesis is performed in a reducing environment.

Superior shuttling of lithium and sodium ions in manganese-doped titania @ functionalized multiwall carbon nanotube anodes

In order to improve the electrochemical kinetics of anatase titania (TiO₂), Mn-doped TiO₂ incorporated with functionalized multiwall carbon nanotubes (MWCNTs) has been prepared by a modified hydrothermal method and tested for both lithium (LIB) and sodium-ion battery (SIB) anodes. The size of the TiO₂ particles is controlled to ∼35-40 nm, with almost even distribution on the MWCNTs surface. The nanostructuring and appropriate doping of cost-effective manganese into the TiO₂ host improved the electrochemical performance in terms of high rate capability and specific capacity for both the rechargeable battery systems. For the LIBs, the charge capacity of the 5% Mn-TiO₂/MWCNT anode is 226.3 mA h g^-1 in the first cycle, and is retained at 176.4 mA h g^-1 after 80 cycles as compared with the SIBs, in which the charge capacity is 152.1 mA h g^-1 in the first cycle, and is retained at 121.4 mA h g^-1 after 80 cycles. After testing the electrodes at a high current rate of 20C, the nanocomposite electrode can still demonstrate charge capacities of 131.2 and 117.2 mA h g^-1 at a 0.1C rate for LIBs and SIBs, respectively. The incorporation of Mn-ions (2+, 4+) is found to play a crucial role in terms of defects and vacancy creation, increasing conduction band electrons and lattice expansion to facilitate alkali metal ion diffusion for superior electrochemical performance. The combination of heteroatom doping and use of a highly conductive additive in the form of MWCNTs has resulted in excellent electrode integrity, high ion accessibility, and fast electron transport. Its outstanding cycling stability and remarkable rate performance make the 5% Mn-TiO₂/MWCNT a promising anode material for high-performance LIBs and SIBs.

Fe3O4 nanoparticles encapsulated in multi-walled carbon nanotubes possess superior lithium storage capability

Fe₃O₄ nanoparticles are successfully introduced inside multi-walled carbon nanotubes (Fe₃O₄@MWNTs) by an innovative wet chemical injection method.

Three-dimensional free-standing carbon nanotubes for a flexible lithium-ion battery anode

Flexible lithium-ion batteries (LIBs) have received considerable attention as energy sources for wearable electronics. In recent years, much effort has been devoted to study light-weight, robust, and flexible electrodes. However, high areal and volumetric capacities need to be achieved for practical power and energy densities. In this paper, we report the use of three-dimensional (3D) free-standing carbon nanotubes (CNTs) as a current collector-free anode to demonstrate flexible LIBs with enhanced areal and volumetric capacities. High density CNTs grown on copper (Cu) mesh are transferred to a flexible graphene/polyethylene terephthalate  film and integrated into a flexible LIB. A fully flexible LIB cell integrated with the 3D CNT anode delivers a high areal capacity of 0.25 mAh cm(-2) at 0.1C and shows fairly consistent open circuit voltage under bending. These findings may provide significant advances in the application of flexible LIB based electronic devices.

Synthesis of cobalt-based layered coordination polymer nanosheets and their application in lithium-ion batteries as anode materials

Layered cobalt-based coordination polymer ([Co(tfbdc) (4,4′-bpy)(H₂O)₂], Co-LCP) nanosheets have been synthesized, which show an excellent performance as anode materials for lithium ion batteries.

Rechargeable Co3O4 porous nanoflake carbon nanotube nanocomposite lithium-ion battery anodes with enhanced energy performances

Multi-walled carbon nanotube nanocomposites intertwined with porous Co₃O₄ nanoflakes serve as lithium-ion battery anode materials with enhanced performances.

Self-assembly synthesis of Co3O4/multiwalled carbon nanotube composites: an efficient enzyme-free glucose sensor

Electrochemical detection and sensing of glucose by direct glucose oxidation using a non-enzymatic sensor with high efficiency and greater stability.

Multi-walled carbon nanotubes composited with nanomagnetite for anodes in lithium ion batteries

The multi-walled carbon nanotube (MWNT) nanocomposites with homogenously anchored nanomagnetite of 10–20 nm prepared by a hydrothermal-annealing method exhibit excellent performances as anode materials for lithium ion batteries.

Solution synthesis of metal oxides for electrochemical energy storage applications

This article provides an overview of solution-based methods for the controllable synthesis of metal oxides and their applications for electrochemical energy storage. Typical solution synthesis strategies are summarized and the detailed chemical reactions are elaborated for several common nanostructured transition metal oxides and their composites. The merits and demerits of these synthesis methods and some important considerations are discussed in association with their electrochemical performance. We also propose the basic guideline for designing advanced nanostructure electrode materials, and the future research trend in the development of high power and energy density electrochemical energy storage devices.

Preparation of composite electrodes with carbon nanotubes for lithium-ion batteries by low-energy ball milling

A method to prepare oxide–carbon nanotube composite electrodes for lithium-ion batteries has been demonstrated. A phase with severe transport limitations, LiFeTiO₄, has been selected as a model electrode material.