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Separators are becoming increasingly important in both academic research and industrial production as a means of enhancing the performance of lithium‐ion batteries (LIBs), particularly at a high rate. However, fast charge–discharge processes will produce local heat accumulation, which accelerates the local reaction rate of Li+ to form lithium dendrites. Commercial polyolefin separators fail to tackle the above issue due to inferior thermal stability. Herein, a core–shell structure is proposed to reinforce the polyvinylidene fluoride‐hexafluoropropylene (PVDF‐HFP) matrix through encircling carbon nanotube (CNT) by adherent polydopamine (PDA). The core–shell 3D structure with PDA avoids the short circuits caused by the electrically conductive CNT, and meantime, the CNT serves as an effective radiator for dispersing local heat sources verified through finite element analysis. The composite separator allows LIBs to achieve high Li+ conductivity (0.49 × 10−3 S cm−1) and Li+ transfer number (0.74), resulting in a high capacity retention of 87.35% after 800 cycles at 5C. In particular, the safety is confirmed that the composite separator avoids violent growth of lithium dendrites caused by local heat accumulation through phase‐field simulations. This work suggests a promising approach for the fabrication of core–shell nanotube composite separators for high‐rate and safe LIBs. [ABSTRACT FROM AUTHOR]

Piezoelectric ceramic and polymeric separators have been proposed to effectively regulate Li deposition and suppress dendrite growth, but such separators still fail to satisfactorily support durable operation of lithium metal batteries owing to the fragile ceramic layer or low‐piezoelectricity polymer as employed. Herein, by combining PVDF‐HFP and ferroelectric BaTiO3, we develop a homogeneous, single‐layer composite separator with strong piezoelectric effects to inhibit dendrite growth while maintaining high mechanical strength. As squeezed by local protrusion, the polarized PVDF‐HFP/BaTiO3 composite separator generates a local voltage to suppress the local‐intensified electric field and further deconcentrate regional lithium‐ion flux to retard lithium deposition on the protrusion, hence enabling a smoother and more compact lithium deposition morphology than the unpoled composite separator and the pure PVDF‐HFP separator, especially at high rates. Remarkably, the homogeneous incorporation of BaTiO3 highly improves the piezoelectric performances of the separator with residual polarization of 0.086 μC cm−2 after polarization treatment, four times that of the pure PVDF‐HFP separator, and simultaneously increases the transference number of lithium‐ion from 0.45 to 0.57. Beneficial from the prominent piezoelectric mechanism, the polarized PVDF‐HFP/BaTiO3 composite separator enables stable cyclic performances of Li||LiFePO4 cells for 400 cycles at 2 C (1 C = 170 mA g−1) with a capacity retention above 99%, and for 600 cycles at 5 C with a capacity retention over 85%. [ABSTRACT FROM AUTHOR]

In tight sandstone reservoirs, diagenesis has a significant impact on the development of reservoirs and pore structures. To clarify the effect of diagenesis on the pore structure of tight sandstone, 12 samples of the Yanchang Formation in the basin were studied based on experiments such as high-pressure mercury intrusion and low-temperature nitrogen adsorption. The diagenetic facies in the study area are divided into two categories: strong cementation facies of carbonate minerals and strong compaction facies of soft component minerals, which are relatively unfavorable diagenetic facies, and stable facies of felsic minerals and strong dissolution facies of feldspar minerals, which are dominant diagenetic facies. The pore structure of the Chang 6 3 reservoir in the study area has obvious fractal characteristics, with a fractal dimension D 1 greater than D 2 and a greater heterogeneity of large pore throats. Compared to compaction and cementation, dissolution has a stronger controlling effect on the pore structure of reservoirs. In tight sandstone reservoirs with low porosity and permeability, dissolution has a more important impact on reservoir transformation and development. The intensity of different types of diagenesis in the Chang 6 3 reservoir affects reservoir heterogeneity, and the level of the reservoir heterogeneity affects the complexity of reservoir pore structure. In tight sandstone reservoirs, cementation has a stronger controlling effect on the structural complexity of large pores, while dissolution has a stronger controlling effect on the structural complexity of small pores. The dissolution has a strong control effect on the physical properties of the reservoir. This study provides insights into the relationships among the diagenetic facies, reservoir quality, and pore structure of tight sandstone reservoirs. This study has reference significance for the exploration and development of tight oil in the research area., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)