Nano-floating gate memory devices with ZnO nano-crystals as charge storage layers are fabricated,and the influence of post-deposition annealing temperature and thickness of the ZnO layer are investigated.Atomic force ...Nano-floating gate memory devices with ZnO nano-crystals as charge storage layers are fabricated,and the influence of post-deposition annealing temperature and thickness of the ZnO layer are investigated.Atomic force microscopy and scanning electron microscopy reveal the morphology of discrete ZnO nano-crystals.For capacitance-voltage measurements,it is found that the memory device with 1.5 nm ZnO and annealed at 700℃shows a larger memory window of 4.3 V（at±6 V）and better retention characteristics than memoriy devices with2.5 nm ZnO or annealed at other temperatures.These results indicate that the nano-floating gate memory with ZnO nano-crystals can obtain good trade-off memory properties.展开更多
Supercapacitors(SCs) are high-power energy storage devices with ultra-fast charge/discharge properties.SCs using concentrated aqueous-based electrolytes can work at low temperatures due to their intrinsic properties, ...Supercapacitors(SCs) are high-power energy storage devices with ultra-fast charge/discharge properties.SCs using concentrated aqueous-based electrolytes can work at low temperatures due to their intrinsic properties, such as higher freezing point depression(FPD) and robustness. Besides the traditional organic-and aqueous-based(salt-in-water) electrolytes used in SCs, water-in-salt(WISE) sodium perchlorate electrolytes offer high FPD, non-flammability, and low-toxicity conditions, allowing the fabrication of safer, environmentally friendly, and more robust devices. For the first time, this work reports a comprehensive study regarding WISE system’s charge-storage capabilities and physicochemical properties under low-temperature conditions(T < 0 ℃) using mesoporous carbon-based electrodes. The effect of temperature reduction on the electrolyte viscosity and electrical properties was investigated using different techniques and the in-situ(or operando) Raman spectroscopy under dynamic polarization conditions.The cell voltage, equivalent series resistance, and specific capacitance were investigated as a function of the temperature. The cell voltage(U) increased ~ 50%, while the specific capacitance decreased ~20%when the temperature was reduced from 25 ℃ to -10 ℃. As a result, the maximum specific energy(E = CU^(2)/2) increased ~ 100%. Therefore, low-temperature WISEs are promising candidates to improve the energy-storage characteristics in SCs.展开更多
Sodium-ion battery materials and devices are promising candidates for largescale applications,owing to the abundance and low cost of sodium sources.Emerging sodium-ion pseudocapacitive materials provide one approach f...Sodium-ion battery materials and devices are promising candidates for largescale applications,owing to the abundance and low cost of sodium sources.Emerging sodium-ion pseudocapacitive materials provide one approach for achieving high capacity at high rates,but are currently not well understood.Herein,a comprehensive overview of the fundamentals and electrochemical behaviors of vanadium-based pseudocapacitive materials for sodium-ion storage is presented.The insight of sodium-ion storage mechanisms for various vanadium-based materials,including vanadium oxides,vanadates,vanadium sulfides,nitrides,and carbides are systematically discussed and summarized.In particular,areas for further development to improve fundamental understanding of electrochemical and structural properties of materials are identified.Finally,we provide a perspective on the application of pseudocapacitive materials in high-power and high-energy sodium-ion storage devices(e.g.,sodium-ion capacitors).展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 61404055
文摘Nano-floating gate memory devices with ZnO nano-crystals as charge storage layers are fabricated,and the influence of post-deposition annealing temperature and thickness of the ZnO layer are investigated.Atomic force microscopy and scanning electron microscopy reveal the morphology of discrete ZnO nano-crystals.For capacitance-voltage measurements,it is found that the memory device with 1.5 nm ZnO and annealed at 700℃shows a larger memory window of 4.3 V（at±6 V）and better retention characteristics than memoriy devices with2.5 nm ZnO or annealed at other temperatures.These results indicate that the nano-floating gate memory with ZnO nano-crystals can obtain good trade-off memory properties.
基金the financial support from the Brazilian funding agencies CNPq(310544/2019-0),FAPESP(2014/02163-7&2017/11958-1)FAPEMIG(Financial support for the LMMA/UFVJM Laboratory)and CNPq(PQ-2 grant:Process 301095/2018-3)the support from Shell and the strategic importance of the support given by ANP(Brazil’s National Oil,Natural Gas,and Biofuels Agency)through the R&D levy regulation。
文摘Supercapacitors(SCs) are high-power energy storage devices with ultra-fast charge/discharge properties.SCs using concentrated aqueous-based electrolytes can work at low temperatures due to their intrinsic properties, such as higher freezing point depression(FPD) and robustness. Besides the traditional organic-and aqueous-based(salt-in-water) electrolytes used in SCs, water-in-salt(WISE) sodium perchlorate electrolytes offer high FPD, non-flammability, and low-toxicity conditions, allowing the fabrication of safer, environmentally friendly, and more robust devices. For the first time, this work reports a comprehensive study regarding WISE system’s charge-storage capabilities and physicochemical properties under low-temperature conditions(T < 0 ℃) using mesoporous carbon-based electrodes. The effect of temperature reduction on the electrolyte viscosity and electrical properties was investigated using different techniques and the in-situ(or operando) Raman spectroscopy under dynamic polarization conditions.The cell voltage, equivalent series resistance, and specific capacitance were investigated as a function of the temperature. The cell voltage(U) increased ~ 50%, while the specific capacitance decreased ~20%when the temperature was reduced from 25 ℃ to -10 ℃. As a result, the maximum specific energy(E = CU^(2)/2) increased ~ 100%. Therefore, low-temperature WISEs are promising candidates to improve the energy-storage characteristics in SCs.
基金support of the Office of Naval Research(ONR grant numbers N000141712244 and N000141912113)support from the National Key R&D Program of China(Grant Number:2016YFA0202602)+1 种基金Natural Science Foundation of Fujian Province of China“Double-First Class”Foundation of Materials and Intel igent Manufacturing Discipline of Xiamen University
文摘Sodium-ion battery materials and devices are promising candidates for largescale applications,owing to the abundance and low cost of sodium sources.Emerging sodium-ion pseudocapacitive materials provide one approach for achieving high capacity at high rates,but are currently not well understood.Herein,a comprehensive overview of the fundamentals and electrochemical behaviors of vanadium-based pseudocapacitive materials for sodium-ion storage is presented.The insight of sodium-ion storage mechanisms for various vanadium-based materials,including vanadium oxides,vanadates,vanadium sulfides,nitrides,and carbides are systematically discussed and summarized.In particular,areas for further development to improve fundamental understanding of electrochemical and structural properties of materials are identified.Finally,we provide a perspective on the application of pseudocapacitive materials in high-power and high-energy sodium-ion storage devices(e.g.,sodium-ion capacitors).
