Currently ether solvents have been regarded as the most compatible organic solvents with lithium metal in electrolytes of lithium batteries.However,ether solvents are unstable under high voltage (>4.0 V),and prone ...Currently ether solvents have been regarded as the most compatible organic solvents with lithium metal in electrolytes of lithium batteries.However,ether solvents are unstable under high voltage (>4.0 V),and prone to side reactions with nickel-rich high-voltage cathode materials.In this work,a novel dual-solvent electrolyte in ethylene glycol dimethyl ether (DME) and butyronitrile (BN) mixed solvent was designed and fabricated for Li/Li Ni_(0.5)Mn_(0.3)Co_(0.2)O_(2)-based lithium metal batteries.When charged to high voltage4.3 V,the battery cycled in this optimal electrolyte can maintain the capacity at 133.7 m Ah g^(-1) with a retention of 88.84%after 150 cycles at 0.2 C and-10℃.During long-term cycling,the battery also exhibits excellent cycling performance with capacity maintained at about 112.0 m Ah g^(-1) after 500 cycles at 1C and-10℃.BN has strong oxidation resistance and high conductivity,which can inhibit the decomposition of ether solvents under high voltage and improve the low temperature performance of battery effectively.Additionally,the cyano (–C≡N) group in BN molecular has a strong coordination ability with the high-valent metal ions and can mask the active ions on the cathode,correspondingly reducing the corrosion of cathode material by the electrolyte.Moreover,cyano group can participate in the hydrolysis to remove trace amounts of water and acidic by-products such as HF in the electrolyte.Therefore,the boosting effect of butyronitrile for ether solvents can provide a promising strategy for enhancing the performance of high voltage lithium metal batteries for practical industrialization.展开更多
The synthesis of methanol and dimethyl ether(DME) from CO hydrogenation has been investigated on Cu-based catalysts.A series of Cu/ZnO/Al2O3 catalysts were prepared using a solvent-free routine which involved a direct...The synthesis of methanol and dimethyl ether(DME) from CO hydrogenation has been investigated on Cu-based catalysts.A series of Cu/ZnO/Al2O3 catalysts were prepared using a solvent-free routine which involved a direct blend of copper/zinc/aluminum salts and citric acid,followed by calcination at 450 °C.The calcination processes were monitored using thermogravimetry differential scanning calorimetry(TG-DSC).Catalysts were further characterized using N2 adsorption,scanning electronic microscopy(SEM),X-ray diffraction(XRD),N2O oxidation followed by H2 titration,and temperature-programmed reduction with H2(H2-TPR).The reduction processes were also monitored with in-situ XRD.The physicochemical properties of catalysts depended strongly on the types of precursor salts,and catalysts prepared using Al acetate and Cu nitrate as starting materials had a larger surface area,larger exposed metallic copper surface area,and lower reduction temperature.The CO hydrogenation performances of these catalysts were compared and discussed in terms of their structures.Catalysts prepared with copper nitrate,zinc and aluminum acetates exhibited the highest catalytic activity.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21978073 and U1903217)Project funded by the China Postdoctoral Science Foundation(No.2019M662574)。
文摘Currently ether solvents have been regarded as the most compatible organic solvents with lithium metal in electrolytes of lithium batteries.However,ether solvents are unstable under high voltage (>4.0 V),and prone to side reactions with nickel-rich high-voltage cathode materials.In this work,a novel dual-solvent electrolyte in ethylene glycol dimethyl ether (DME) and butyronitrile (BN) mixed solvent was designed and fabricated for Li/Li Ni_(0.5)Mn_(0.3)Co_(0.2)O_(2)-based lithium metal batteries.When charged to high voltage4.3 V,the battery cycled in this optimal electrolyte can maintain the capacity at 133.7 m Ah g^(-1) with a retention of 88.84%after 150 cycles at 0.2 C and-10℃.During long-term cycling,the battery also exhibits excellent cycling performance with capacity maintained at about 112.0 m Ah g^(-1) after 500 cycles at 1C and-10℃.BN has strong oxidation resistance and high conductivity,which can inhibit the decomposition of ether solvents under high voltage and improve the low temperature performance of battery effectively.Additionally,the cyano (–C≡N) group in BN molecular has a strong coordination ability with the high-valent metal ions and can mask the active ions on the cathode,correspondingly reducing the corrosion of cathode material by the electrolyte.Moreover,cyano group can participate in the hydrolysis to remove trace amounts of water and acidic by-products such as HF in the electrolyte.Therefore,the boosting effect of butyronitrile for ether solvents can provide a promising strategy for enhancing the performance of high voltage lithium metal batteries for practical industrialization.
基金supported by the National Natural Science Foundation of China (Nos. 21073159 and 90610002)the National Basic Research Program (973) of China (No. 2007CB210207)the Zhejiang Provincial Natural Science Foundation of China (No. Z406142)
文摘The synthesis of methanol and dimethyl ether(DME) from CO hydrogenation has been investigated on Cu-based catalysts.A series of Cu/ZnO/Al2O3 catalysts were prepared using a solvent-free routine which involved a direct blend of copper/zinc/aluminum salts and citric acid,followed by calcination at 450 °C.The calcination processes were monitored using thermogravimetry differential scanning calorimetry(TG-DSC).Catalysts were further characterized using N2 adsorption,scanning electronic microscopy(SEM),X-ray diffraction(XRD),N2O oxidation followed by H2 titration,and temperature-programmed reduction with H2(H2-TPR).The reduction processes were also monitored with in-situ XRD.The physicochemical properties of catalysts depended strongly on the types of precursor salts,and catalysts prepared using Al acetate and Cu nitrate as starting materials had a larger surface area,larger exposed metallic copper surface area,and lower reduction temperature.The CO hydrogenation performances of these catalysts were compared and discussed in terms of their structures.Catalysts prepared with copper nitrate,zinc and aluminum acetates exhibited the highest catalytic activity.
