Boron-doped high-entropy oxide toward high-rate and long-cycle layered cathodes for wide-temperature sodium-ion batteries

03-type layered metal oxides hold great promise for sodium-ion batteries cathodes owing to their energy density advantage.However,the severe irreversible phase transition and sluggish Na^(+)diffusion kinetics pose significant challenges to achieve high-performance layered cathodes.Herein,a boron-doped03-type high entropy oxide Na(Fe_(0.2)Co_(0.15)Cu_(0.05)Ni_(0.2)Mn_(0.2)Ti_(0.2))B_(0.02)O_(2)(NFCCNMT-B_(0.02))is designed and the covalent B-O bonds with high entropy configuration ensure a robust layered structure.The obtained cathode NFCCNMT-B_(0.02)exhibits impressive cycling performance(capacity retention of 95%and 82%after100 cycles and 300 cycles at 1 and 10 C,respectively)and outstanding rate capability(capacity of 83 mAh g^(-1)at 10 C).Furthermore,the NFCCNMT-B_(0.02)demonstrates a superior wide-temperature performance,maintaining the same capacity level(113,4 mAh g^(-1)@-20℃,121 mAh g^(-1)@25℃,and 119 mAh g^(-1)@60℃)and superior cycle stability(90%capacity retention after 100 cycles at 1 C at-20℃).The high-entropy configuration design with boron doping strategy contributes to the excellent sodium-ion storage performance.The high-entropy configuration design effectively suppresses irreversible phase transitions accompanied by small volume changes(ΔV=0.65 A3).B ions doping expands the Na layer distance and enlarges the P3 phase region,thereby enhancing Na^(+)diffusion kinetics.This work offers valuable insights into design of high-performance layered cathodes for sodium-ion batteries operating across a wide temperature.

Effect of additives on iron recovery and dephosphorization by reduction roasting-magnetic separation of refractory high-phosphorus iron ore

The effect of CaCO_(3),Na_(2)CO_(3),and CaF_(2) on the reduction roasting and magnetic separation of high-phosphorus iron ore containing phosphorus in the form of Fe_(3)PO_(7) and apatite was investigated.The results revealed that Na_(2)CO_(3) had the most significant effect on iron recovery and dephosphorization,followed by CaCO_(3),the effect of CaF_(2) was negligible.The mechanisms of CaCO_(3),Na_(2)CO_(3),and CaF_(2) were investigated using X-ray diffraction(XRD),scanning electron microscopy and energy dispersive spectrometry(SEM-EDS).Without additives,Fe_(3)PO_(7) was reduced to elemental phosphorus and formed an iron-phosphorus alloy with metallic iron.The addition of CaCO_(3) reacted with Fe_(3)PO_(7) to generate an enormous amount of Ca_(3)(PO_(4))_(2) and promoted the reduction of iron oxides.However,the growth of iron particles was inhibited.With the addition of Na_(2)CO_(3),the phosphorus in Fe_(3)PO_(7) migrated to nepheline and Na_(2)CO_(3) improved the reduction of iron oxides and growth of iron particles.Therefore,the recovery of iron and the separation of iron and phosphorus were the best.In contrast,CaF_(2) reacted with Fe_(3)PO_(7) to form fine Ca_(3)(PO_(4))2 particles scattered around the iron particles,making the separation of iron and phosphorus difficult.

D-serine reduces memory impairment and neuronal damage induced by chronic lead exposure

Although exogenous D-serine has been applied as a neural regulatory intervention in many studies,the role played by D-serine in hippocampal injuries caused by lead exposure remains poorly understood.Rat models of chronic lead exposure were established through the administration of 0.05%lead acetate for 8 weeks.Simultaneously,rats were administered 30 or 60 mg/kg D-serine,intraperitoneally,twice a day.Our results showed that D-serine treatment shortened the escape latency from the Morris water maze,increased the number of times that mice crossed the original platform location,and alleviated the pathological damage experienced by hippocampal neurons in response to lead exposure.Although D-serine administration did not increase the expression levels of the N-methyl-D-aspartate receptor subtype 2B(NR2B)in the hippocampi of lead-exposed rats,60 mg/kg D-serine treatment restored the expression levels of NR2A,which are reduced by lead exposure.These findings suggested that D-serine can alleviate learning and memory impairments induced by lead exposure and that the underlying mechanism is associated with the increased expression of NR2A in the hippocampus.This study was approved by the Animal Ethics Committee of North China University of Science and Technology,China(approval No.LX2018155)on December 21,2018.

Dynamic Expression Profiles of Marker Genes in Osteogenic Differentiation of Human Bone Marrow-derived Mesenchymal Stem Cells

Objective To observe the expression profiles of osteoblast-related genes in human mesenchymal stem cells(MSCs) derived from bone marrow during osteogenic differentiation. Methods MSCs were induced to differentiate with MSC osteogenic differentiation medium for 7, 14, 21 and 28 days respectively. Alizarin Red staining was used to detect matrix mineralization. Expression of osteoblast-related genes, including osteocalcin, osteopontin, Runt-related transcription factor 2(Runx2), alkaline phosphatase and collagen type Ⅰ, was assessed with quantitative reverse transcription-polymerase chain reaction. Results On day 14 after induction of differentiation, cells were stained positively with Alizarin Red. The expression levels of these genes exhibited an upward trend as induction time was prolonged. Exposure to osteogenic differentiation medium less than 21 days did not significantly induce osteocalcin expression; osteocalcin expression levels in the differentiated cells induced for 21 and 28 days were 1.63 and 2.46 times as high as the undifferentiated cells respectively(all P<0.05). Stimulation with MSC osteogenic differentiation medium over 14 days significantly enhanced bone marrow-derived MSCs to express osteopontin and Runx2 genes(all P<0.05). Osteogenic differentiation medium could significantly induce the expressions of alkaline phosphatase and collagen type Ⅰgenes(all P<0.05). Their expressions reached the peak levels on day 21, which were increased more than 4- and 3-fold respectively. Conclusion Human bone marrow-derived MSCs could exhibit the sequential expression pattern of osteoblast marker genes during osteogenic differentiation in vitro.

High-temperature chlorination of gold with transformation of iron phase

Gold in cyanide tailings from Shandong Province is mainly encapsulated by hematite and magnetite at distribution rates of 76.49 % and 10.88 %, respectively.Chlorination-reduction one-step roasting of cyanide tailings was conducted under the following conditions： calcium chloride dosage of 6 %, bituminous coal dosage of 30 %, calcium oxide dosage of 10 %（all dosages are vs.the mass of cyanide tailings） at 1000 ℃ of roasting temperature. X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and chemical-phase analysis were performed to investigate the effects of iron phase transformation on the high-temperature chlorination of gold.Results indicate that the lattice structure of hematite undergoes expansion, pulverization, and reorganization when hematite is reduced to magnetite, which leads to42.03 % gold exposure, and the high-temperature chlorination rate of gold is 41.17 % at the same time. The structure of wustite formed by the reduction in magnetite is porous and loose, and thus 44.02 % of gold is exposed. The high-temperature chlorination rate of gold is increased by41.98 percentage points. When wustite is reduced to metallic iron, 4.42 % of gold is exposed, and the hightemperature chlorination rate of gold is increased by3.38 percentage points. Accordingly, the high-temperature chlorination of gold mainly occurs in two stages, in which Fe_2O_3 is reduced to Fe_3O_4, and Fe_3O_4 is reduced to Fe_xO finally.