Nitrogen-doped TiO2(B) nanobelts enabling enhancement of electronic conductivity and efficiency of lithium-ion storage

To enhance the intrinsic electrical conductivities of TiO₂(B) nanobelts, nitrogen(N)-doped TiO₂(B) nanobelts (N-TNB) were prepared in this study by a facile and cost-effective hydrothermal method using urea as the nitrogen source with TiO₂ (P25) nanoparticles. x-ray photoelectron spectroscopy confirmed that the N-atoms preferentially occupied up to ∼0.516 atom% in the interstitial sites of the N-TNB and the maximum concentration of substituted-N bonds in the N-TNB was ∼0.154 atom%, thereby the total concentration of doped nitrogen elements of ∼0.67 atom% improved the high intrinsic electrical conductivity and ionic diffusivity of the TiO₂(B) nanobelts. The as-prepared N-TNB electrode delivered the highest specific capacity of 133.9 mAh g^-1 in the first cycle, with an exceptional cyclic capacity retention at an ultrafast current rate of 1000 mA g^-1; this is not less than 51% after 500 cycles and represents an excellent rate capability of ∼37 mAh g^-1 at an ultra-high rate of 40 C. These values are among the best ever reported on comparison of the delivered highest discharge capacity of N-TNB at 1000 mA g^-1 and high-rate capabilities of its Li⁺ ion storage with the literature data for N-TNB (∼231.5 mAh g^-1 at a very low current density of 16.75 mA g^-1, ∼0.1 C) of similar materials used in sodium-ion batteries. This implies the potential feasibility of these N-TNB as high-capacity anode materials for next-generation, high-energy-density, electrochemical energy-storage devices.

Ti-Based Oxide Anode Materials for Advanced Electrochemical Energy Storage: Lithium/Sodium Ion Batteries and Hybrid Pseudocapacitors

Titanium-based oxides including TiO₂ and M-Ti-O compounds (M = Li, Nb, Na, etc.) family, exhibit advantageous structural dynamics (2D ion diffusion path, open and stable structure for ion accommodations) for practical applications in energy storage systems, such as lithium-ion batteries, sodium-ion batteries, and hybrid pseudocapacitors. Further, Ti-based oxides show high operating voltage relative to the deposition of alkali metal, ensuring full safety by avoiding the formation of lithium and sodium dendrites. On the other hand, high working potential prevents the decomposition of electrolyte, delivering excellent rate capability through the unique pseudocapacitive kinetics. Nevertheless, the intrinsic poor electrical conductivity and reaction dynamics limit further applications in energy storage devices. Recently, various work and in-depth understanding on the morphologies control, surface engineering, bulk-phase doping of Ti-based oxides, have been promoted to overcome these issues. Inspired by that, in this review, the authors summarize the fundamental issues, challenges and advances of Ti-based oxides in the applications of advanced electrochemical energy storage. Particularly, the authors focus on the progresses on the working mechanism and device applications from lithium-ion batteries to sodium-ion batteries, and then the hybrid pseudocapacitors. In addition, future perspectives for fundamental research and practical applications are discussed.

TiO₂ Nanobelt@Co₉S₈ Composites as Promising Anode Materials for Lithium and Sodium Ion Batteries

TiO₂ anodes have attracted great attention due to their good cycling stability for lithium ion batteries and sodium ion batteries (LIBs and SIBs). Unfortunately, the low specific capacity and poor conductivity limit their practical application. The mixed phase TiO₂ nanobelt (anatase and TiO₂-B) based Co₉S₈ composites have been synthesized via the solvothermal reaction and subsequent calcination. During the formation process of hierarchical composites, glucose between TiO₂ nanobelts and Co₉S₈ serves as a linker to increase the nucleation and growth of sulfides on the surface of TiO₂ nanobelts. As anode materials for LIBs and SIBs, the composites combine the advantages of TiO₂ nanobelts with those of Co₉S₈ nanomaterials. The reversible specific capacity of TiO₂ nanobelt@Co₉S₈ composites is up to 889 and 387 mAh·g⁻¹ at 0.1 A·g⁻¹ after 100 cycles, respectively. The cooperation of excellent cycling stability of TiO₂ nanobelts and high capacities of Co₉S₈ nanoparticles leads to the good electrochemical performances of TiO₂ nanobelt@Co₉S₈ composites.

Enhanced cell viability of hydroxyapatite nanowires by surfactant mediated synthesis and its growth mechanism

Hydroxyapatite (HA) nanowires were synthesized using cetyl-trimethyl-ammonium-bromide (CTAB) as a surfactant and exhibited enhanced cell viability over other HA nanostructures.

Interconnected mesoporous NiO sheets deposited onto TiO2nanosheet arrays as binder-free anode materials with enhanced performance for lithium ion batteries

TiO₂nanosheet arrays were synthesized by a hydrothermal method as a stable backbone for subsequent chemical bath deposition of interconnected NiO sheets.