Strong Li-Content Dependence of Li Diffusivity in TiO₂-B

Abstract

The lithiation process in TiO 2 -B as a function of Li content x is studied using density functional theory. Considering a variety of possible pathways, we find that stepwise insertion of Li in TiO 2 -B layers, followed by insertion of Li in O layers, is kinetically the most favorable scenario. Diffusion coefficient (D) varies only by 2 orders of magnitude with x for Li contents up to x = 0.75 (3.03 × 10 −10 cm 2 /s ≤ D ≤ 7.94 × 10 −8 cm 2 /s), but it becomes almost 6 and 26 orders of magnitude smaller for 0.75 < x ≤ 1.0 and 1.00 < x < 1.25, respectively. To make a direct comparison to experimental measurements, the maximum diffusion length was estimated for different values of C-rate. It is found that, for any reasonable value of C-rate between 0.1C and 10C, bulk TiO 2 -B cannot attain capacities larger than 251 mAh g −1 . However, larger capacities up to 335 mAh g −1 can be obtained by nanosized TiO 2 -B. In addition, we find that a capacity higher than 335 mAh g −1 cannot be achieved. Our results suggest that the small discharge capacity of bulk TiO 2 -B is due to the large increase in the energy barrier of Li diffusion for Li contents above x = 0.75.

Recent Progress in Ruthenium Oxide‐Based Composites for Supercapacitor Applications

“…[252] The ternary composite showed impressive electrochemical features, as demonstrated in Figure 16. [253] Comparative study of the ternary-3D-RuO 2 /graphitic C 3 N 4 /rGO-aerogel (RCGA)and binary 3D-RuO 2 / rGO aerogel composite (RGA)composite shows that the former sample electrode exhibits near-rectangular CV curves indicating better supercapacitive behavior with higher current densities at varying potential scan rates as observed in Figure 16(a)-(b). Better electrochemical performance of the ternary composite over binary is depicted from galvanostatic charging and discharging (GCD) measurements as well (Figure 16(c)-(d)).…”

“…RuO 2 and graphitic-C 3 N 4 combination increased the pseudocapacitive as well as the EDLC of graphene so that the ternary system exhibited high gravimetric capacitance of~704.3 F g À 1 measured at 0.5 A g À 1 specific current with good capacity retention efficiency (Figure 16(d-f). [253] Similarly, anodic deposition technique has been adapted for fabricating a ternary RuO 2 ·xH 2 O/rGO/CNT nanocomposite onto Ti current collector. The ternary composite displayed exceptionally high specific capacitance of~1210 F g À 1 under low optimum RuO 2 loading at 25 mV s À 1 scan rate with good capacitance retention.…”

“…Here, RGCA = 3D RuO 2 /g-C 3 N 4 @reduced graphene oxide (rGO) aerogel composite and RGA = 3D RuO 2 /rGO aerogel composite respectively. Reproduced with permission from Ref [253]…”

Photoluminescence, cathodoluminescence and thermal stability of Sm3+‐activated Sr3La(VO4)3 red‐emitting phosphors

“…6 H J (J = 5/2, 7/2, 9/2, 11/2). [10][11][12] It has been reported that Sm 3+ -activated Sr 2 CaWO 6 phosphors can exhibit bright red emissions and may have promising application in WLEDs. [13] Conversely, as is known, the luminescence properties of the RE ions are largely dependent on the host material, Abbreviations used: CL, cathodoluminescence; CN, coordinate number; CR, cross-relaxation; CRI, color rendering index; CT, charge transfer; ED, electric dipole; LED, light-emitting diode; MD, magnetic dipole; NR, non-radiative; NUV, near ultraviolet; PL, photoluminescence; PLE, photoluminescence excitation; PTI, Photon Technology International; RE, rare-earth; XRD, X-ray diffraction.…”

Copper(I)‐Catalyzed Decarboxylative Coupling of Propiolic Acids with Secondary Amines and Aldehydes

“…[16] In recent years, enormous progress has been made to expand the scope of the direct addition of alkynes to carbonnitrogen double bonds either from prepared imines or from aldehydes and amines in a one-pot procedure with various transition-metal catalysts through C-H activation of terminal alkynes. These include Ag I salts, [17] Au I /Au II salts, [18] Au III -salen complexes, [19] Cu I salts, [20] Hg 2 Cl 2 , [21] and Cu/ Ru dimetallic systems [22] under homogeneous conditions. Recently, Au III [23] and Ag I [24] in ionic liquids were used to catalyze A 3 -coupling reactions.…”