Enhanced Rate Capability and Low-Temperature Performance of Li₄Ti₅O₁₂ Anode Material by Facile Surface Fluorination

A commercial Li₄Ti₅O₁₂ material was modified by NH₄F using a facile and dry method at a low temperature in air. X-ray diffraction reveals that the fluorination did not change the bulk structure of Li₄Ti₅O₁₂. X-ray photoelectron spectroscopy demonstrates that LiF was formed at the surface and Ti⁴⁺ was partially changed into Ti³⁺. Microscopic images show that some nanoislands were formed on the surface, which enlarged the surface area. Consequently, the NH₄F-modified Li₄Ti₅O₁₂ material exhibited significantly enhanced capacities and rate capabilities, even at low temperatures. The discharge capacity was increased from 149 to 167 mA h g^–1 at 1 C, and the capacity retention was increased from 17.8 to 52.0% at 15 C. The capacity retention of NH₄F-modified Li₄Ti₅O₁₂ was greater than that of Li₄Ti₅O₁₂ at each low-temperature point. Additionally, the introduction of F can protect the Li₄Ti₅O₁₂ material from side reactions with the electrolyte and the atmosphere, enhancing the surface stability and reducing the release of gaseous products. It is believed that the NH₄F-modified Li₄Ti₅O₁₂ with enhanced electrochemical performance is a promising anode material for lithium ion batteries. Furthermore, this facile surface fluorination strategy is amenable to large-scale production

Additional file 1: Table S1. of Evaluation of different nested PCRs for detection of Anaplasma phagocytophilum in ruminants and ticks

Nucleotide sequence accession numbers of A. phagocytophilum, A. centrale, A. ovis, A. marginale, A. bovis, Anaplasma sp. and R. rickettsii isolates analyzed in this study. (DOCX 35 kb