Metal oxides represent a set of promising materials for use as electrodes within lithium ion batteries, but unfortunately, these tend to suffer from limitations associated with poor ionic and electron conductivity as well as low cycling performance. Hence, to achieve the goal of creating economical, relatively less toxic, thermally stable, and simultaneously high-energy-density electrode materials, we have put forth a number of targeted strategies, aimed at rationally improving upon electrochemical performance. Specifically, in this Perspective, we discuss the precise roles and effects of controllably varying not only (i) morphology but also (ii) chemistry as a means of advancing, ameliorating, and fundamentally tuning the development and evolution of Fe3O4, Li4Ti5O12, TiO2, and LiV3O8 as viable and ubiquitous energy storage materials.

This report describes the first detailed electrochemical examination of a series of copper birnessite samples under lithium-based battery conditions, allowing a structure/function analysis of the electrochemistry and related material properties. To obtain the series of copper birnessite samples, a novel synthetic approach for the preparation of copper birnessite, CuxMnOy·nH2O is reported. The copper content (x) in CuxMnOy·nH2O, 0.28 ≥ x ≥ 0.20, was inversely proportional to crystallite size, which ranged from 12 to 19 nm. The electrochemistry under lithium-based battery conditions showed that the higher copper content (x = 0.28) and small crystallite size (∼12 nm) sample delivered ∼194 mAh/g, about 20% higher capacity than the low copper content (x = 0.22) and larger crystallite size (∼19 nm) material. In addition, CuxMnOy·nH2O displays quasi-reversible electrochemistry in magnesium based electrolytes, indicating that copper birnessite could be a candidate for future application in magnesium-ion batteries.

Titanium oxide is a ubiquitous and commonly used material in the environment. Herein, we have systematically probed the use of various hydrothermally derived titania (TiO2) architectures including zero-dimensional (0D) nanoparticles, one-dimensional (1D) nanowires, and three-dimensional (3D) urchin-like motifs as anode materials for lithium-ion batteries. The structure and morphology of these nanomaterials were characterized using electron microscopy. The surface areas of these materials were quantitatively analyzed through Brunauer–Emmett–Teller (BET) adsorption measurements and were found to be relatively similar for both 1D and 3D samples with a slightly higher surface area associated with the 0D nanoparticles. Hence, to normalize for the surface area effect, readily available 0D commercial nanoparticles (Degussa P25), which possessed a similar surface area to that of as-prepared 1D and 3D materials, were also analyzed. Electrochemical analysis revealed a superior performance of hydrothermally derived 3D urchin-like motifs as compared with both as-prepared 0D and 1D samples as well as commercial Degussa P25. Our studies suggest the greater overall importance of morphology as opposed to surface area in dictating the efficiency of the Li ion diffusion process. Specifically, the 3D urchins yielded consistent rate capabilities, delivering 214, 167, 120, 99, and 52 mAh/g under corresponding discharge rates of 0.1, 1, 10, 20, and 50 C, respectively. Moreover, these 3D motifs gave rise to a stable cycling performance, exhibiting a capacity retention of ∼90% in cycles 1–100 under a discharge rate of 1 C. Furthermore, the rate capability and cycling performance of our 3D hierarchical motifs were (i) comparable to those of anatase TiO2/TiO2-(B) hybrid structures even with little if any electrochemically promising bronze (B) phase herein and (ii) clearly enhanced as compared with previous results using similar anatase 3D microspheres.

A research project for senior undergraduates of chemistry has been developed to introduce syntheses of a series of monodispersed semiconductor PbS quantum dots (QDs) and their characterization methodologies. In this paper, we report the preparation of monodispersed semiconductor PbS QDs with sizes smaller than the exciton Bohr radius using a simple, one-step process, and the characterization of the QDs using a range of instruments, including Fourier-transform infrared spectroscopy, transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and energy-dispersive X-ray spectroscopy. Our synthesis approach involves dissolving powdered sulfur (as the S precursor) in 1-tetradecene and adding PbCl 2 as the Pb precursor to the suspension as well as oleylamine as a capping ligand. The PbS QD project represents, we believe, an almost ideal opportunity to provide exposure of undergraduate students to nanotechnology research via syntheses and characterization of semiconductor nanoparticles.A dvances in nanotechnology in the past 20 years have resulted in enormous interest in introducing nanomaterials and associated technologies into the undergraduate curriculum, especially in chemistry. 1−6 As examples, Pavel et al. 2 have reported experiments involving a scattering species, rhodamine 6G (R6G), adsorbed onto silver nanoparticles (AgNPs), with the purpose of quantitatively measuring the surface-enhanced Raman scattering (SERS) phenomenon for the system; this study also incorporated absorbance and emission measurements. Reid et al. 3 developed a laboratory experiment involving semiconductor ZnO quantum dots (QDs) focusing on band gap 3 and absorbance characterization. Also, Lisensky et al. 6 discussed a laboratory experiment involving absorbance and emission characterization of semiconductor CdSe QDs. However, most of the reported studies involve theoretical issues that are somewhat sophisticated for undergraduate chemical education purposes. In this article, we present our recently developed research project of semiconductor QD synthesis and characterization to help to promote and improve college-level education focusing on undergraduate research. We also demonstrate that an undergraduate research project can be conveniently utilized as a laboratory experiment for curriculum development purposes.The main reason we selected lead sulfide QDs to introduce nanoscience research to our undergraduates is that lead sulfide QDs can be conveniently synthesized under mild temperature in a simple, one-step noninjection process. Our approach significantly reduce burn risks to undergraduates that may occur when high-temperature syntheses are undertaken. In addition, undergraduates can gain some basic knowledge related to semiconductor QDs and their applications.Semiconductor lead chalcogenide (PbS, PbSe, PbTe) QD materials show strong quantum confinement effects due to their relative large exciton Bohr radii and dielectric constants. 7,8 The quantum confinement phenomenon 3 associated with lead chalcogenide QDs can be easily obs...