采用ASTM C 1202《混凝土抵抗氯离子渗透能力的电量评价方法》,研究了不同干燥条件对混凝土导电量的影响;在电量试验结束后,检测了氯离子的迁移量和氯离子渗透深度.结果表明:60℃,7 d的干燥条件对水胶比小于0.42且不掺矿物掺和料的基准...采用ASTM C 1202《混凝土抵抗氯离子渗透能力的电量评价方法》,研究了不同干燥条件对混凝土导电量的影响;在电量试验结束后,检测了氯离子的迁移量和氯离子渗透深度.结果表明:60℃,7 d的干燥条件对水胶比小于0.42且不掺矿物掺和料的基准混凝土及水胶比小于0.49但掺加矿物掺和料的混凝土导电量影响很小,该条件可以作为气体渗透试验的干燥条件;105℃的干燥处理需要慎重,因为该条件会导致混凝土导电量及氯离子迁移量明显增加,混凝土抗渗性能变差;对于电量试验后氯离子渗透深度贯穿的试样,导电量评价标准已不适于评价此类试样的渗透性能,可以考虑将氯离子迁移量或试样的饱水量作为评价其渗透性能的一个定量指标.展开更多
Pursuing all-solid-state lithium metal batteries with dual upgrading of safety and energy density is of great significance. However, searching compatible solid electrolyte and reversible conversion cathode is still a ...Pursuing all-solid-state lithium metal batteries with dual upgrading of safety and energy density is of great significance. However, searching compatible solid electrolyte and reversible conversion cathode is still a big challenge. The phase transformation at cathode and Li deformation at anode would usually deactivate the electrode-electrolyte interfaces. Herein, we propose an all-solid-state Li-FeF_(3) conversion battery reinforced by hierarchical microsphere stacked polymer electrolyte for the first time. This gC_(3)N_(4) stuffed polyethylene oxide(PEO)-based electrolyte is lightweight due to the absence of metal element doping, and it enables the spatial confinement and dissolution suppression of conversion products at soft cathode-polymer interface, as well as Li dendrite inhibition at filler-reinforced anode-polymer interface. Two-dimensional(2 D)-nanosheet-built porous g-C_(3)N_(4) as three-dimensional(3 D) textured filler can strongly cross-link with PEO matrix and Li TFSI(TFSI: bistrifluoromethanesulfonimide) anion, leading to a more conductive and salt-dissociated interface and therefore improved conductivity(2.5×10^(-4) S/cm at 60℃) and Li+transference number(0.69). The compact stacking of highly regular robust microspheres in polymer electrolyte enables a successful stabilization and smoothening of Li metal with ultra-long plating/striping cycling for at least 10,000 h. The corresponding Li/LiFePO_(4) solid cells can endure an extremely high rate of 12 C. All-solid-state Li/FeF_(3) cells show highly stabilized capacity as high as 300 m Ah/g even after 200 cycles and of 200 m Ah/g at extremely high rate of 5 C, as well as ultra-long cycling for at least 1200 cycles at 1 C. High pseudocapacitance contribution(>55%) and diffusion coefficient(as high as10^(-12) cm^(2)/s) are responsible for this high-rate fluoride conversion. This result provides a promising solution to conversion-type Li metal batteries of high energy and safety beyond Li-S batteries, which are difficult to realize true "all-solid-state" due to the indispensable step of polysulfide solid-liquid conversion.展开更多
文摘采用ASTM C 1202《混凝土抵抗氯离子渗透能力的电量评价方法》,研究了不同干燥条件对混凝土导电量的影响;在电量试验结束后,检测了氯离子的迁移量和氯离子渗透深度.结果表明:60℃,7 d的干燥条件对水胶比小于0.42且不掺矿物掺和料的基准混凝土及水胶比小于0.49但掺加矿物掺和料的混凝土导电量影响很小,该条件可以作为气体渗透试验的干燥条件;105℃的干燥处理需要慎重,因为该条件会导致混凝土导电量及氯离子迁移量明显增加,混凝土抗渗性能变差;对于电量试验后氯离子渗透深度贯穿的试样,导电量评价标准已不适于评价此类试样的渗透性能,可以考虑将氯离子迁移量或试样的饱水量作为评价其渗透性能的一个定量指标.
基金supported by the National Key R&D Program of China (2016YFB0901600),NSAF (U1830113)the National Natural Science Foundation of China (51772313 and 21975276)Shanghai Science and Technology Committee (20520710800)。
文摘Pursuing all-solid-state lithium metal batteries with dual upgrading of safety and energy density is of great significance. However, searching compatible solid electrolyte and reversible conversion cathode is still a big challenge. The phase transformation at cathode and Li deformation at anode would usually deactivate the electrode-electrolyte interfaces. Herein, we propose an all-solid-state Li-FeF_(3) conversion battery reinforced by hierarchical microsphere stacked polymer electrolyte for the first time. This gC_(3)N_(4) stuffed polyethylene oxide(PEO)-based electrolyte is lightweight due to the absence of metal element doping, and it enables the spatial confinement and dissolution suppression of conversion products at soft cathode-polymer interface, as well as Li dendrite inhibition at filler-reinforced anode-polymer interface. Two-dimensional(2 D)-nanosheet-built porous g-C_(3)N_(4) as three-dimensional(3 D) textured filler can strongly cross-link with PEO matrix and Li TFSI(TFSI: bistrifluoromethanesulfonimide) anion, leading to a more conductive and salt-dissociated interface and therefore improved conductivity(2.5×10^(-4) S/cm at 60℃) and Li+transference number(0.69). The compact stacking of highly regular robust microspheres in polymer electrolyte enables a successful stabilization and smoothening of Li metal with ultra-long plating/striping cycling for at least 10,000 h. The corresponding Li/LiFePO_(4) solid cells can endure an extremely high rate of 12 C. All-solid-state Li/FeF_(3) cells show highly stabilized capacity as high as 300 m Ah/g even after 200 cycles and of 200 m Ah/g at extremely high rate of 5 C, as well as ultra-long cycling for at least 1200 cycles at 1 C. High pseudocapacitance contribution(>55%) and diffusion coefficient(as high as10^(-12) cm^(2)/s) are responsible for this high-rate fluoride conversion. This result provides a promising solution to conversion-type Li metal batteries of high energy and safety beyond Li-S batteries, which are difficult to realize true "all-solid-state" due to the indispensable step of polysulfide solid-liquid conversion.
