A density functional theory (DFT) study has been carried out on transition metal phosphates with olivine structure and formula LiMPO4 (M = Fe, Mn, Co, Ni) to assess their potential as cathode materials in rechargeable Li-ion batteries based on their chemical and structural stability and high theoretical capacity. The investigation focuses on LiMnPO4, which could offer an improved cell potential...

Nickel was doped into Li3VO4 (Ni-LVO) successfully via a facile room temperature reaction, and the resulting Ni-LVO nanocrystallites showed excellent lithium-ion storage properties with a capacity of 650 mAh g−1 at 50 mAh g−1 and excellent capacity stability as an anode in lithium-ion batteries, maintaining nearly 100% of the initial reversible capacity after 800 cycles at 1 A g−1. The superior...

We present a method of measurement of the extraordinary refractive index dispersion in MIR for periodically and aperiodically poled nonlinear crystals with unknown or uncertain periods. The method is based on the spontaneous parametric down-conversion and is useful for the crystals with domain structure formed directly in the process of growth by Czochralski technique. As an example we measure ...

Ab initio density-functional theory study suggests that pillared Li-dispersed boron carbide nanotubes is capable of storing hydrogen with a mass density higher than 6.0 weight% and a volumetric density higher than 45 g/L. The boron substitution in carbon nanotube greatly enhances the binding energy of Li atom to the nanotube, and this binding energy (~ 2.7 eV) is greater than the cohesive energ...

A facile and low-cost strategy is demonstrated for preparing MnO/C-N hybrid, in which the MnO nanoparticles chemically combine with N-doped C by Mn-N bonding to achieve the hybridization of MnO with N-doped C. When served as an anode in lithium ion batteries (LIBs), the resultant hybrid manifested high capacity, excellent cyclability, and superior rate capability. A lithium storage capacity of ...

In this paper dielectric properties of LiNbO3:Gd single crystals at temperatures ~ 290–490 K at narrow frequency range (0.5–10 6 Hz) are presented. The influence of growth conditions was also investigated. The anomalies on dielectric plots depend on the development of the microand nano-domain structure.

周期分極反転素子は,いまや波長変換において欠かせないデバイス であり,その作製技術には高い関心が集まっている.光アシストによ る分極反転法は,従来の櫛型構造電極を用いた分極反転法と比べ,よ り細かい周期の分極反転構造を作製できる方法として注目されてい る.本論文では,下図に示すような光学配置により,ニオブ酸リチウ ム結晶における光照射の分極反転への影響を調べた.著者らは可視光 照射により分極反転ドメインの核形成電場が大幅に減少することを発 見し,その減少率はノンドープ結晶で30%,マグネシウムドープ結 晶で約90%に達するという結果を得ている.また,このような効果 は光照射をしているときのみ起こり,入射する面の方向 (+C面, -C面)には依存しないとも報告している.(図3,表1,文献18) 光アシストによる分極反転のメカニズムは,いまだ解明されていな い部分が多い.本論文のような研...

We have used density-functional theory generalized gradient approximation GGA to study lithium intercalation at low concentration into anatase TiO2. To describe the defect states produced by Li doping a Hubbard “+U” correction is applied to the Ti d states GGA+U . Uncorrected GGA calculations predict LixTiO2 to be metallic with the excess charge distributed over all Ti sites, whereas GGA+U pred...

"EXAFS and EPR analysis of the local structure of Mn-doped Li 2 B 4 O 7 " (2013). Peter Dowben Publications. 264. The local structure of Mn-doped Li 2 B 4 O 7 (001) was investigated using extended X-ray absorption fine structure (EXAFS) at the Mn K edge and electron paramagnetic resonance (EPR). The location of the Mn dopant in a lithium tetraborate crystal is consistent with occupation of a si...

Illumination of photorefractive, iron-doped lithium niobate crystals (LiNbO3 :Fe) with x-rays generates a conductivity that we determine from the speed of hologram erasure. The doping levels of the crystals and the acceleration voltage of our x-ray tube are varied. A theoretical model is presented, which describes the obtained results. A decrease of the conductivity with increasing Fe concentra...