Compared to traditional extraction of lithium using solar evaporation, the electrochemical extraction is advantageous in many aspects, including elevated efficiency, superior selectivity, and low environmental pollution. In this study, LiNi 0·038 Mo 0·012 Mn 1·95 O 4 (LNMMO) with good lattice structure and nano morphology was successfully prepared and confirmed by XRD (X-ray diffraction), SEM-Mapping (scanning electron microscope mapping), SEM (scanning electron microscope), and EDX (Energy-dispersive X-ray spectroscopy) analyses. The pairing of LNMMO with activated carbon (AC) yielded obvious cost-effective and environmentally friendly composite when compared to conventional Noble metals used for battery anodes, such as Ag and Pt. A hybrid supercapacitor was assembled using delithiated LNMMO cathode (NMMO) and AC anode to form NMMO/AC. The cell showed high capacity, high rate performance, and excellent cyclic stability. A continuous flow NMMO/AC hybrid supercapacitor (CF-NMMO/AC) was developed for selective capture of Li + in aqueous solution by combining NMMO/AC hybrid supercapacitor with self-designed continuous flow control system. The device delivered high Li + extraction efficiencies reaching 14.4 mg/g per one cycle in simulated brine by consuming only 7.91 W h/mol Li + . The overall process produced 97.2％ Li + in simulated brine at optimized operating conditions. Overall, CF-NMMO/AC system provided higher efficiency, superior selectivity, and moderate energy utilization for Li + recovery from brine.
Weiqiang Hu,Zhi Dong,Hui Wang,Tansir Ahamad,Zongqing Ma
Oxide-dispersion-strengthened (ODS) tungsten based alloys with high performance were synthesized by optimized freeze-drying with PVP and PEG polymer dispersant additives and subsequent low temperature sintering . The pre-freezing principle developed firstly in our work shows that fast cooling rate and polymer dispersant additives contribute to the refinement and uniformity of precursor powders. The optimized freeze-dried W-Y 2 O 3 composite powders possess an average grain size of 9 nm, which can be attributed to the steric hindrance provided by polymer dispersants during freeze-drying and voids left by the decomposition of polymer dispersants during calcination . After sintering at low temperature, the W-Y 2 O 3 alloys have ultrafine W grain (210 nm) and nano second phase particles (<50 nm) dispersed in W matrix while maintaining a high relative density of 97.8%. These factors mentioned above lead to the microhardness and compressive strength as high as 721 ± 31 HV 0.2 , 814 MPa respectively, accompanied by a high total deformation plasticity of above 50%. These results indicate that the optimized freeze-drying and subsequent low temperature sintering is a promising way to fabricate ODS tungsten based alloys with high performance.
Al 2 O 3 –ZrO 2 (3Y)–SiC ceramic composites were prepared by spark plasma sintering in vacuum under 40 MPa of uniaxial compression between 1300 °C and 1400 °C. The effect of nano-size SiC and sintering temperature on the microstructure and mechanical properties of ceramic composites were investigated. The results showed that SiC particles was uniformly distributed in the composite, mainly within the matrix grains. Sintering temperature and SiC particles caused the shape of alumina grains to be columnar. The flexural strength of 22.3 vol% Al 2 O 3 -57.7 vol% ZrO 2 -20 vol% SiC sintered at 1350 °C composites was 1081 MPa, fracture toughness was 15.18 MPa m 1/2 and hardness was 16.42 GPa. The addition of SiC particles leads to grain boundary strengthening, and the change of fracture mode and cracks deflection and bridging are considered to be the main reasons for the increase in material fracture toughness.
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