Li-ion battery technology has become very important in recent years as these batteries show great promise as power sources that can lead us to the electric vehicle (EV) revolution. The development of new materials for Li-ion batteries is the focus of research in prominent groups in the field of materials science throughout the world. Li-ion batteries can be considered to be the most impressive success story of modern electrochemistry in the last two decades. They power most of today's portable devices, and seem to overcome the psychological barriers against the use of such high energy density devices on a larger scale for more demanding applications, such as EV. Since this field is advancing rapidly and attracting an increasing number of researchers, it is important to provide current and timely updates of this constantly changing technology. In this review, we describe the key aspects of Li-ion batteries: the basic science behind their operation, the most relevant components, anodes, cathodes, electrolyte solutions, as well as important future directions for R&D of advanced Li-ion batteries for demanding use, such as EV and load-leveling applications.

Challenges in the development of advanced Li-ion batteries: a review

Research Development on Sodium-Ion Batteries

[Liu, Chang; Li, Feng; Ma, Lai-Peng; Cheng, Hui-Ming] Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China.;Cheng, HM (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, 72 Wenhua Rd, Shenyang 110016, Peoples R China;cheng@imr.ac.cn

Advanced Materials for Energy Storage

Since the discovery of mechanically exfoliated graphene in 2004, research on ultrathin two-dimensional (2D) nanomaterials has grown exponentially in the fields of condensed matter physics, material science, chemistry, and nanotechnology. Highlighting their compelling physical, chemical, electronic, and optical properties, as well as their various potential applications, in this Review, we summarize the state-of-art progress on the ultrathin 2D nanomaterials with a particular emphasis on their recent advances. First, we introduce the unique advances on ultrathin 2D nanomaterials, followed by the description of their composition and crystal structures. The assortments of their synthetic methods are then summarized, including insights on their advantages and limitations, alongside some recommendations on suitable characterization techniques. We also discuss in detail the utilization of these ultrathin 2D nanomaterials for wide ranges of potential applications among the electronics/optoelectronics, electrocat...

Recent Advances in Ultrathin Two-Dimensional Nanomaterials

Metal Oxides and Oxysalts as Anode Materials for Li Ion Batteries

Nanoflakes of α-Fe2O3 were prepared on Cu foil by using a thermal treatment method. The nanoflakes were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and Raman spectroscopy. The reversible Li-cycling properties of the α-Fe2O3 nanoflakes have been evaluated by cyclic voltammery, galvanostatic discharge–charge cycling, and impedance spectral measurements on cells with Li metal as the counter and reference electrodes, at ambient temperature. Results show that Fe2O3 nanoflakes exhibit a stable capacity of (680 ± 20) mA h g–1, corresponding to (4.05 ± 0.05) moles of Li per mole of Fe2O3 with no noticeable capacity fading up to 80 cycles when cycled in the voltage range 0.005–3.0 V at 65 mA g–1 (0.1 C rate), and with a coulombic efficiency of > 98 % during cycling (after the 15th cycle). The average discharge and charge voltages are 1.2 and 2.1 V, respectively. The observed cyclic voltammograms and impedance spectra have been analyzed and interpreted in terms of the ‘conversion reaction' involving nanophase Fe0–Li2O. The superior performance of Fe2O3 nanoflakes is clearly established by a comparison of the results with those for Fe2O3 nanoparticles and nanotubes reported in the literature.

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α‐Fe2O3 Nanoflakes as an Anode Material for Li‐Ion Batteries

We report the fabrication of vertically aligned NiO nanowalls on nickel foils using a plasma assisted oxidation method. Electrochemical properties of as-synthesized NiO nanowalls were evaluated by galvanostatic cycling and cyclic voltammetery. The results show a capacity of ∼638 (mA h)/g (at 1.25C rate), with excellent capacity retention of up to 85 cycles, when cycled in the range, 0.005−3.0 V vs Li. The superior electrochemical performance of NiO nanowalls in comparison to the previously reported results on nanosized NiO particles can be attributed to its large surface area and shorter diffusion length for mass and charge transport. A possible reaction mechanism is discussed. We also report that electron field emission studies show that the verticllay aligned NiO nanowalls are efficient field emitters with a turn-on field of 7.4 V/µm and a maximum current density of ∼160 µA/cm2 can be achieved.

Fabrication of NiO Nanowall Electrodes for High Performance Lithium Ion Battery

Polymorphs of 1D nanostructures of niobium pentoxide (Nb2O5) are synthesized by electrospinning. Pseudohexagonal (H−Nb2O5), orthorhombic (O−Nb2O5), and monoclinic (M−Nb2O5) structures of Nb2O5 are developed in this study by appropriate heat treatment. Morphological, structural, and electrochemical properties of these nanofibrous polymorphs are studied in detail. The H− and O− phases maintain the usual fibrous morphology, whereas the M− phase adopted a distorted nugget structure. These phases are evaluated for their application as cathode for lithium batteries. The M−Nb2O5 exhibits the highest capacity and better capacity retention compared to the other phases. The M−Nb2O5 delivers a specific capacity of 242(±3) and 218(±3) mAhg−1, cycled at a current of 50 mAg−1 in the voltage range, 1.0−2.6 V versus Li/Li+ at the end of second and 25th cycle, respectively. The electrospun M−Nb2O5 nuggets-based battery performs better than its particle/nanofiber counterpart and could be a cathode material of choice for 2 ...

Nanostructured Nb2O5 Polymorphs by Electrospinning for Rechargeable Lithium Batteries

Metal sulfides, known as being analogous to metal oxides, have emerged as a new class of materials for energy conversion and/or storage applications due to their low cost and high electrochemical activity. They have shown fascinating properties such as excellent redox reversibility, conductivity, and capacitance. Further, binary metal sulfides have gained enormous attention due to their large redox reaction sites and high electrical conductivity compared to metal sulfides. Recently, use of binary metal sulfides as electrode materials for various applications such as lithium-ion batteries (LIBs), supercapacitors (SC), and solar cells has been extensively studied by various research groups and this review critically overviews the strategies and advances made towards attaining high performances from these sulfides in an effort to provide leads for scale-up and to find long term solutions for energy and environment crisis. Finally, challenges in achieving superior performances and the future scope of research for metal sulfide based energy materials have been outlined.

M. V. Reddy

Papers

Metal Oxides and Oxysalts as Anode Materials for Li Ion Batteries

α‐Fe2O3 Nanoflakes as an Anode Material for Li‐Ion Batteries

Fabrication of NiO Nanowall Electrodes for High Performance Lithium Ion Battery

Nanostructured Nb2O5 Polymorphs by Electrospinning for Rechargeable Lithium Batteries

Nanostructured binary and ternary metal sulfides: synthesis methods and their application in energy conversion and storage devices