In order to balance the conductivity and flexural strength of graphite composite bipolar plates,the influence of conductive filler on the properties of graphite composite bipolar plate was comprehensively studied by u...In order to balance the conductivity and flexural strength of graphite composite bipolar plates,the influence of conductive filler on the properties of graphite composite bipolar plate was comprehensively studied by using phenolic resin as binder,natural flake graphite as conductive substrate and functional carbon materials with different structures as auxiliary filler.The results show that the particle size of conductive substrate has an important influence on the conductivity enhancement of auxiliary filler.The influence of conductive particle size on auxiliary filler electrical conductivity improvement was first investigated in this research.The effects of various auxiliary filler concentrations on improving electrical conductivity and flexural strength were then examined.This research has substantial implications for the balance of electrical conductivity and flexural strength of graphite composite bipolar plates.展开更多
A method of size exclusion chromatography coupled with ultraviolet spectrophotometry and off-line graphite furnace atomic absorption spectrometry was developed to assess the complexation properties of iron（Fe） and h...A method of size exclusion chromatography coupled with ultraviolet spectrophotometry and off-line graphite furnace atomic absorption spectrometry was developed to assess the complexation properties of iron（Fe） and humic acid（HA） in a water environment. The factors affecting the complexation of Fe and HA, such as ionic strength, pH, temperature and UV radiation, were investigated. The Fe–HA complex residence time was also studied. Experimental results showed that pH could influence the deprotonation of HA and hydrolysis of Fe, and thus affected the complexation of Fe and HA. The complexation was greatly disrupted by the presence of NaCl. Temperature had some influence on the complexation. The yield of Fe–HA complexes showed a small decrease at high levels of UV radiation, but the effect of UV radiation on Fe–HA complex formation at natural levels could be neglected. It took about 10 hr for the complexation to reach equilibrium, and the Fe–HA complex residence time was about 20 hr.Complexation of Fe and HA reached a maximum level under the conditions of pH 6, very low ionic strength, in the dark and at a water temperature of about 25°C, for 10 hr. It was suggested that the Fe–HA complex could form mainly in freshwater bodies and reach high levels in the warm season with mild sunlight radiation. With changing environmental parameters, such as at lower temperature in winter or higher pH and ionic strength in an estuary, the concentration of the Fe–HA complex would decrease.展开更多
基金the financial supports from the National Key R&D Program of China(Nos.2020YFB1505904 and 2018YFB1502502-04)。
文摘In order to balance the conductivity and flexural strength of graphite composite bipolar plates,the influence of conductive filler on the properties of graphite composite bipolar plate was comprehensively studied by using phenolic resin as binder,natural flake graphite as conductive substrate and functional carbon materials with different structures as auxiliary filler.The results show that the particle size of conductive substrate has an important influence on the conductivity enhancement of auxiliary filler.The influence of conductive particle size on auxiliary filler electrical conductivity improvement was first investigated in this research.The effects of various auxiliary filler concentrations on improving electrical conductivity and flexural strength were then examined.This research has substantial implications for the balance of electrical conductivity and flexural strength of graphite composite bipolar plates.
基金supported by the National Natural Science Foundation of China (No. 41176075)
文摘A method of size exclusion chromatography coupled with ultraviolet spectrophotometry and off-line graphite furnace atomic absorption spectrometry was developed to assess the complexation properties of iron（Fe） and humic acid（HA） in a water environment. The factors affecting the complexation of Fe and HA, such as ionic strength, pH, temperature and UV radiation, were investigated. The Fe–HA complex residence time was also studied. Experimental results showed that pH could influence the deprotonation of HA and hydrolysis of Fe, and thus affected the complexation of Fe and HA. The complexation was greatly disrupted by the presence of NaCl. Temperature had some influence on the complexation. The yield of Fe–HA complexes showed a small decrease at high levels of UV radiation, but the effect of UV radiation on Fe–HA complex formation at natural levels could be neglected. It took about 10 hr for the complexation to reach equilibrium, and the Fe–HA complex residence time was about 20 hr.Complexation of Fe and HA reached a maximum level under the conditions of pH 6, very low ionic strength, in the dark and at a water temperature of about 25°C, for 10 hr. It was suggested that the Fe–HA complex could form mainly in freshwater bodies and reach high levels in the warm season with mild sunlight radiation. With changing environmental parameters, such as at lower temperature in winter or higher pH and ionic strength in an estuary, the concentration of the Fe–HA complex would decrease.
