Electrospun TiO₂–rGO Composite Nanofibers with Ordered Mesopores by Molecular Level Assembly: A High Performance Anode Material for Lithium‐Ion Batteries

Abstract

cycling especially on fast changing rate due to their low lithium intercalation potential (≈0.1 V vs Li/Li + ), resulting the risk of short circuit that may end up with thermal explosion. [7] Whereas, in case of TiO 2 anode materials, not only its relatively high discharge potential (≈1.7 V vs Li/Li + ) suppresses the formation of lithium dendrites but also its low volume expansion during lithiation/delithiation improves long cycling durability and inhibits the formation of solid electrode interface. [8,9] Thus these two aspects of TiO 2 synergistically facilitate superior safety of batteries along with a theoretical capacity of ≈170 mAh g -1 which is comparable with the commercialized cathode material. [10] Additionally, TiO 2 materials are of low cost, nontoxic, chemically and thermally stable. All these properties make TiO 2 advantageous anode material for lithium ion battery application. Unfortunately, the electrochemical performances of TiO 2 is still challenging due to its low electronic conductivity and Li-ion diffusivity inducing a poor rate capability. [11] In addition to that, uses of TiO 2 nanoparticle anodes are restricted by other several issues like particle agglomeration and dissolution during cycling that result in decrease in electroactive area and performance degradation. Present research on this field has made considerable effort to fabricate dimensionally controlled nanostructured TiO 2 with high surface area to enhance the energy storage performances. [12,13] This is because nanostructured materials offer shortening of Li + diffusion path, large interfacial active area, and also possess the ability to relax the strain generated during Li + insertion/extraction process. [14][15][16] In this perspective 1D nanomaterials such as nanotubes or nanofibers are good choice to satisfy all these criteria due to their large specific surface area and high aspect ratio (surface to volume ratio) which assure favorable transport of both the electrons and Li + . [3,17,18] On the other side, porosity within the structure not only enables high rate capability by decreasing the polarization resistance but also it allows easy access of active sites for Li + , electrons and electrolyte resulting improved kinetics favorable for better cycle performance and storage capacity. [19][20][21] Moreover, Li storage performances in The authors report a novel strategy to fabricate electrospun anatase TiO 2 -rGO composite nanofibers with 3D cubic ordered mesoporosity. Such synthesis route not only ensures molecular level composite formation between rGO and TiO 2 but also retains the rGO content and orders mesostructure after calcination of the nascent fiber at an optimum condition that only removes the surfactant and polymer. Transmission electron microscopic and low angle X-ray diffraction studies confirm the presence of ordered mesoporosity within the nanofibers. Raman and X-ray photoelectron spectroscopy studies reveal the molecular level composite formation between rGO and TiO 2 with chemical bonding. This composite nano...

A Review of Recent Advancements in Electrospun Anode Materials to Improve Rechargeable Lithium Battery Performance

“…10 −12 − 10 −7 S/cm)) [ 66 , 83 , 84 , 85 , 86 ]. Designing one-dimensional nanostructures through the electrospinning process is considered an efficient route to overcome the diffusion issue related to the reduced lithium-ion diffusion path and a high surface-to-volume ratio [ 84 ]. Figure 7 shows the representative TiO 2 one-dimensional nanostructures.…”

“…There have been efforts to improve the electrical conductivity of the TiO 2 nanofibers. It is simple and intuitive to composite the TiO 2 nanofibers with conducting materials such as gold or silver nanoparticles [ 83 , 90 ], reduced graphene oxide (rGO) [ 66 , 84 ], and hard carbon [ 85 ]. By extension, silver paste has been used to adhere the TiO 2 active materials and current collector and to provide the electrical conducting pathway to the active materials [ 91 ], and the surfaces of the hollow TiO 2 nanofibers were nitridated to increase electrical conductivity [ 92 ].…”

Rational design and kinetics study of flexible sodium-ion full batteries based on binder-free composite film electrodes

“…C n is the double layer capacitance on the electrode surface. They represent the ion transport across the six interphases, such as (1) the interphase between HCF and NVP, R ct1 through HCF and insertion capacity (C 1 ), (2) the interphase between NVP and the solid electrolyte interphase (SEI), R ct2 through NVP and insertion capacity (C 2 ), (3) the interphase between the electrolyte and SEI, R ct3 through SEI and insertion capacity (C 3 ), (4) the interphase between the electrolyte and SEI, R ct4 through SEI and insertion capacity (C 4 ), (5) the interphase between the SEI and GN/SiC, R ct5 through GN/SiC and insertion capacity (C 5 ), and (6) the interphase between GN/SiC and HCF, R ct6 through HCF and insertion capacity (C 6 ). According to the Nyquist plots in Fig.…”

“…Developing new and low-cost technologies in environmentally friendly energy storage systems is a life-time goal for researchers. [1][2][3][4][5] With the rapidly increasing demand for versatile energy storage devices, great interest has been aroused in exible/bendable electronic equipment, such as rollup displays, wearable and portable electronic devices and implantable biomedical products. [6][7][8] Nevertheless, exible rechargeable batteries still suffer from the lack of advanced electrodes with high energy density, high reversible capacities, fast chargedischarge rates and a long lifespan.…”

Strongly Surface‐Bonded MoO2@Carbon Nanocomposites by Nitrogen‐Doping with Outstanding Capability for Fast and Stable Li Storage

“…At present, graphite is widely used as the anode material of LIBs, however, its low theoretical specific capacity (372 mA h g −1 ) and sluggish kinetics for Li + insertion/extraction seriously limit the further application of LIBs in high‐energy and high‐power devices . Under these circumstances, transition metal oxides are attracting significant attention due to their high capacity, low cost, and environmental friendliness . In particular, molybdenum dioxide (MoO 2 ) stands out among numerous potential candidates because of its high theoretical capacity of 838 mA h g −1 and low electrical resistivity .…”