The
use of TiNb2O7 (TNO) as an anode material
for Li-ion battery is attracting tremendous attention because of its
stable structure and high theoretical capacity. However, the inherent
poor electronic conductivity and ionic conductivity restrict its practical
application. Herein, we designed and prepared zirconium-doped TiNb2O7 nanospheres (Zr
x
-TNO NSs, x = 0, 0.05, 0.010) with pores through
a simple hydrolysis method to adjust the lattice spacing and electron
distribution. The nanosphere-structured electron materials with pores
can not only prevent aggregation of active materials but also provide
more channels for Li+ and electrons’ transportation.
Meanwhile, X-ray diffraction coupled with high-resolution transmission
electron microscopy results verified the crystal spacing increasement.
The X-ray photoelectron spectrum exhibited partial reduction of metal
atoms. As a result, Zr0.05-TNO NSs showed improved cycling
stability in the half cell (i.e., delivers a reversible capacity of
170 mA h/g at 5 C after 1000 cycles). It also showed excellent performance
in the rate capabilities of 260.0 and 177.8 mA h/g at 0.5 and 10 C,
making it highly competitive for quick-charging lithium-ion batteries.
NiMgAlO catalysts were prepared by two methods: coprecipition and impregnation. They were used to simultaneously adsorb SO2and NO with O2in a fixed bed at atmospheric pressure. Typically the molar composition of the feed gas was 1% SO2, 0.2% NO and O2with ultra-high purity Ar as the diluent. The results showed the catalysts were excellent materials for the simultaneous oxidation adsorption of SO2and NOx. The two kinds of catalysts were compared for the SO2and NOx adsorption capacity. The NiMgAlO catalyst prepared by coprecipition had better adsorption than impregnation. When NiMgAlO catalysts with 10 wt-% Ni content were calcined at 550°C, adsorption capacity was the largest at 120°C adsorption temperature: 1.392 mmol SO2and 0.213 mmol NOx were adsorbed on 1 g catalyst prepared by the coprecipition method. The causes are seen by the XRD, surface area and porous size analysis.
Microporous carbons (MCs) for supercapacitors were prepared from coal tar pitch (CTP) with potassium hydroxide (KOH) as activating agent at different KOH/CTP mass ratio by different heating modes. The results show that the specific surface area (SBET), micropore surface area (Smic), total pore volume (Vt) and micropore volume ((Vmic) of MCs made by microwave heating at 30 min heating time increases with the KOH/CTP mass ratio, respectively. At 14/7 of the KOH/CTP mass ratio, the SBET of MCs made by microwave heating at 30 min heating time reaches 1786 m2/g while that of MCs made by conventional heating at 180 min heating time is 1769 m2/g. The specific capacitance and energy density of the former reaches 269 F/g and 9.2 Wh/kg in 6 M KOH aqueous electrolyte while that of the latter is up to 307 F/g and 10.5 Wh/kg, respectively. And yet, the former brings bigger MC yield and bigger retention of energy density. The effects of the pore size distribution and pore volume on the specific capacitance and energy density of MC samples with the similar SBET by different heating modes are addressed in this paper.
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