Aqueous alkaline rechargeable batteries(ARBs)have huge potential in energy storage equipment because of their low cost,safety and high ionic conductivity.However,the performance of actual ARBs is largely limited by el...Aqueous alkaline rechargeable batteries(ARBs)have huge potential in energy storage equipment because of their low cost,safety and high ionic conductivity.However,the performance of actual ARBs is largely limited by electrode materials.Here,the CoNiMn-LDH cathode with a hollow cubic structure and the Bi_(2)O_(3) anode with a rod-shaped structure were successfully prepared using MOFs as templates.Compared with binary CoNi-LDH,the ternary CoNiMn-LDH has a larger voltage window,higher capacity,and faster charge transport dynamics and ion diffusion dynamics.A full battery was assembled with CoNiMn-LDH and Bi_(2)O_(3),and exhibited a high specific capacity of 247.32 mA h g^(−1) at 1 A g^(−1).It exhibited cycling stability for up to 1400 cycles and its capacity retention was 87% at 4 A g^(−1).In addition,a high energy density of 120 W h kg^(−1) could also be achieved at a power density of 4219 W kg^(−1).This study provides an instructive paradigm for the design and preparation of advanced electrode materials for full batteries.展开更多
The enhancement of gibbsite precipitation in Bayer process by 33 kHz ultrasound has been studied. From orthome-thod experiment, the optimized operating parameters of treatment under 33 kHz ultrasonic cleaner have obta...The enhancement of gibbsite precipitation in Bayer process by 33 kHz ultrasound has been studied. From orthome-thod experiment, the optimized operating parameters of treatment under 33 kHz ultrasonic cleaner have obtained. Compared with crystallization of AI(OH)3 without treatment of ultrasound, the precipitation time is reduced by 15 h when the precipitation ratio is 45%. From the results of grain size distribution and SEM photographs of gibbsite, it is found that secondary nucleation and agglomeration could be enhanced under 33 kHz ultrasound. The products are same from comparison of X-ray powder diffraction, but the Raman spectrum of sodium aluminate solution under 33 kHz ultrasound is different from that without ultrasound.展开更多
Large trihydroxy bauxite deposit was once considered unavailable in China.With the prospecting think-ing of diwa theory,the author has drawn a contrary conclusion.From the view of the law of progression with transform...Large trihydroxy bauxite deposit was once considered unavailable in China.With the prospecting think-ing of diwa theory,the author has drawn a contrary conclusion.From the view of the law of progression with transformation between mobile and stable regions and the metallogenic specialization of tectonic elements,he reveals the principal reason why the known bauxite deposits in China are mostly of monohydroxide type,and acquires the way of searching for trihydroxide bauxite deposits.He considers that the residual-mobility period of the diwa stage in the crustal development in South China pocesses-tectonic conditions favourable to the formation of bauxite deposits of this type.He believes that the Cenozoic structural sublayer of the residual-mobility period of the diwa stage developed on the carbonate rock of the Paleozoic platformal structural layer is the preferrential target of prospecting.With this thinking and many years of efforts,we have gained prelimi-nary achievements and have discovered Guigang-type latee-ritic trihydroxied bauxite deposits in Guangxi.In future,by extension and analogy of the thinking,we are likely to find large,high-grade bauxite deposits in its vicinity and to discover weathering-type bauxite deposits with other parent rocks.展开更多
Aluminum(Al)transformations between solid and liquid states in the Na_(2)O:Al_(2)O_(3):H_(2)O system often involve changes in coordination and polymerization,with the intermediate molecular states challenging to resol...Aluminum(Al)transformations between solid and liquid states in the Na_(2)O:Al_(2)O_(3):H_(2)O system often involve changes in coordination and polymerization,with the intermediate molecular states challenging to resolve.To detect Al transformations in situ,a solid-state mixture of sodium hydroxide monohydrate(NaOH·H_(2)O)and boehmite(AlOOH)was heated above the melting point of NaOH·H_(2)O to dissolve AlOOH and prepare nonasodium bis(hexahydroxyaluminate)trihydroxide hexahydrate(NSA).In situ 27Al magic angle spinning,nuclear magnetic resonance(MAS NMR)spectroscopy was used to monitor Al speciation and coordination during AlOOH dissolution into a homogenous melt,and the crystallization of NSA during cooling to room temperature,supported with ex situ X-ray diffraction,Raman spectroscopy,and 27Al multiple-quantum,3QMAS NMR spectroscopy.Novel metastable aluminate species were identified during the transformation.Dissolution of AlOOH in molten NaOH·H_(2)O entails a transition from octahedral Al in AlOOH to tetrahedral Al in the aluminate anion[Al(OH)_(4)]^(−)and mu-oxo aluminate dimer[Al_(2)O(OH)_(6)]^(2−)present in solution.These tetrahedral solution-state species then precipitate to form an intermediate,amorphous,tetrahedrally coordinated,sodium aluminate hydrate phase which is stable at 70℃,and subsequentially crystallizes during cooling to form monomeric octahedral Al in the NSA structure.These transformations and associated intermediates provide insight into the molecular scale mechanisms of Al coordination changes,which in this case appear to be mediated by an amorphous precursor containing oligomerized,tetrahedral Al.展开更多
基金supported by the National Natural Science Foundation of China(22269024)Ph.D.Research Startup Foundation of Yan’an University(YDBK2020-22)+1 种基金Technology Innovation Leading Program of Shaanxi(2022QFY07-04)Joint Project between Department of Science&Technology and the Local Government in Shaanxi(2022GD-TSL-66,2022GD-TSL-68).
文摘Aqueous alkaline rechargeable batteries(ARBs)have huge potential in energy storage equipment because of their low cost,safety and high ionic conductivity.However,the performance of actual ARBs is largely limited by electrode materials.Here,the CoNiMn-LDH cathode with a hollow cubic structure and the Bi_(2)O_(3) anode with a rod-shaped structure were successfully prepared using MOFs as templates.Compared with binary CoNi-LDH,the ternary CoNiMn-LDH has a larger voltage window,higher capacity,and faster charge transport dynamics and ion diffusion dynamics.A full battery was assembled with CoNiMn-LDH and Bi_(2)O_(3),and exhibited a high specific capacity of 247.32 mA h g^(−1) at 1 A g^(−1).It exhibited cycling stability for up to 1400 cycles and its capacity retention was 87% at 4 A g^(−1).In addition,a high energy density of 120 W h kg^(−1) could also be achieved at a power density of 4219 W kg^(−1).This study provides an instructive paradigm for the design and preparation of advanced electrode materials for full batteries.
基金The authors would like to acknowledge the support by the National Priority Development Project Fundamental Research(G1999064902-3)the National Natural Science Foundation of China(59874031).
文摘The enhancement of gibbsite precipitation in Bayer process by 33 kHz ultrasound has been studied. From orthome-thod experiment, the optimized operating parameters of treatment under 33 kHz ultrasonic cleaner have obtained. Compared with crystallization of AI(OH)3 without treatment of ultrasound, the precipitation time is reduced by 15 h when the precipitation ratio is 45%. From the results of grain size distribution and SEM photographs of gibbsite, it is found that secondary nucleation and agglomeration could be enhanced under 33 kHz ultrasound. The products are same from comparison of X-ray powder diffraction, but the Raman spectrum of sodium aluminate solution under 33 kHz ultrasound is different from that without ultrasound.
文摘Large trihydroxy bauxite deposit was once considered unavailable in China.With the prospecting think-ing of diwa theory,the author has drawn a contrary conclusion.From the view of the law of progression with transformation between mobile and stable regions and the metallogenic specialization of tectonic elements,he reveals the principal reason why the known bauxite deposits in China are mostly of monohydroxide type,and acquires the way of searching for trihydroxide bauxite deposits.He considers that the residual-mobility period of the diwa stage in the crustal development in South China pocesses-tectonic conditions favourable to the formation of bauxite deposits of this type.He believes that the Cenozoic structural sublayer of the residual-mobility period of the diwa stage developed on the carbonate rock of the Paleozoic platformal structural layer is the preferrential target of prospecting.With this thinking and many years of efforts,we have gained prelimi-nary achievements and have discovered Guigang-type latee-ritic trihydroxied bauxite deposits in Guangxi.In future,by extension and analogy of the thinking,we are likely to find large,high-grade bauxite deposits in its vicinity and to discover weathering-type bauxite deposits with other parent rocks.
基金supported by IDREAM(Interfacial Dynamics in Radioactive Environments and Materials),an Energy Frontier Research Center funded by the U.S.Department of Energy(DOE),Office of Science,Basic Energy Sciences(BES)XRD,Raman spectroscopy,and NMR spectroscopy were performed using facilities at the Environmental Molecular Science Laboratory(EMSL,grid.436923.9),a DOE Office of Science User Facility sponsored by the Office of Biological and Environmental Research at Pacific Northwest National Laboratory(PNNL)+1 种基金PNNL is a multiprogram national laboratory operated for DOE by Battelle Memorial Institute operating under Contract No.DE AC05-76RL0-1830The 14.1 T NMR spectrometer was acquired with support from the BES Chemical Sciences,Geosciences,&Biosciences(CSGB)Division。
文摘Aluminum(Al)transformations between solid and liquid states in the Na_(2)O:Al_(2)O_(3):H_(2)O system often involve changes in coordination and polymerization,with the intermediate molecular states challenging to resolve.To detect Al transformations in situ,a solid-state mixture of sodium hydroxide monohydrate(NaOH·H_(2)O)and boehmite(AlOOH)was heated above the melting point of NaOH·H_(2)O to dissolve AlOOH and prepare nonasodium bis(hexahydroxyaluminate)trihydroxide hexahydrate(NSA).In situ 27Al magic angle spinning,nuclear magnetic resonance(MAS NMR)spectroscopy was used to monitor Al speciation and coordination during AlOOH dissolution into a homogenous melt,and the crystallization of NSA during cooling to room temperature,supported with ex situ X-ray diffraction,Raman spectroscopy,and 27Al multiple-quantum,3QMAS NMR spectroscopy.Novel metastable aluminate species were identified during the transformation.Dissolution of AlOOH in molten NaOH·H_(2)O entails a transition from octahedral Al in AlOOH to tetrahedral Al in the aluminate anion[Al(OH)_(4)]^(−)and mu-oxo aluminate dimer[Al_(2)O(OH)_(6)]^(2−)present in solution.These tetrahedral solution-state species then precipitate to form an intermediate,amorphous,tetrahedrally coordinated,sodium aluminate hydrate phase which is stable at 70℃,and subsequentially crystallizes during cooling to form monomeric octahedral Al in the NSA structure.These transformations and associated intermediates provide insight into the molecular scale mechanisms of Al coordination changes,which in this case appear to be mediated by an amorphous precursor containing oligomerized,tetrahedral Al.
