Transactions of Nonferrous Metals Society of China (中国有色金属学报)•2026•DOI: 10.1016/S1003-6326(26)67065-3
Polycrystalline LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes undergo intergranular cracking and structural collapse during extended cycling, limiting their commercial viability. This study reports single-crystalline NCM811 synthesized via a rapid ethanol–water solvothermal method. The solvothermal duration was varied, and the 60 min sample (NCM-60) exhibited optimal electrochemical performance. X-ray diffractometry confirmed an α-NaFeO2 structure with R-3m space group and high crystallinity. NCM-60 delivered a reversible capacity of 157.28 mA·h/g at 1C and a capacity retention of 55.06% after 200 cycles, significantly outperforming polycrystalline NCM (PC-NCM). Cross-sectional scanning electron microscopy revealed no apparent cracks in NCM-60 after 200 cycles, whereas PC-NCM exhibited severe intergranular fracture. The results demonstrate that shortening solvothermal time reduces precursor particle size and crystallinity, but 60 min yields the best balance. Pre-oxidation of the carbonate precursor before lithiation is recommended to mitigate CO2 evolution and lithium–nickel disorder during high-temperature sintering. This rapid solvothermal route offers a scalable pathway to single-crystal NCM811 with enhanced cycling stability and mechanical integrity.
Journal of Central South University•2026•DOI: 10.1007/s11771-026-6256-8
This study integrates true triaxial hydraulic fracturing experiments with finite-discrete element method (FDEM) numerical simulation to systematically investigate the control mechanisms of interface strength and inclination angle on hydraulic fracture propagation in coal measure strata under different in-situ stress conditions. The results indicate that the fracture propagation path at the rock interface is jointly controlled by the interface strength coefficient (η), the interface inclination angle (θ), and the vertical stress difference coefficient (k). When fractures propagate from soft rock to hard rock, the interface strength coefficient (η) plays a dominant role. The larger the η is, the more likely the hydraulic fracture is to penetrate the interface along the direction of vertical stress. Conversely, when fractures propagate from hard rock to soft rock, vertical stress primarily controls the propagation path. A larger vertical stress difference coefficient promotes interface crossing, while a smaller coefficient tends to cause the fracture to extend laterally along the interface. The interface inclination angle influences the magnitude and direction of the vertical stress component along the interface. A smaller θ facilitates interface penetration by hydraulic fractures, whereas a larger θ leads to fracture propagation along the interface. The complexity of the hydraulic fracture network increases with higher k and θ . Moreover, the complexity of hydraulic fracture morphology exhibits a non-monotonic trend, initially decreasing and then increasing with rising k and θ. This research provides an important theoretical basis for the design and control of hydraulic fracturing in coal measure strata.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01697-1
The transition to renewable energy sources has elevated the importance of SIBs (SIBs) as cost-effective alternatives to lithium-ion batteries (LIBs) for large-scale energy storage. This review examines the mechanisms of gas generation in SIBs, identifying sources from cathode materials, anode materials, and electrolytes, which pose safety risks like swelling, leakage, and explosions. Gases such as CO2, H2, and O2 primarily arise from the instability of cathode materials, side reactions between electrode and electrolyte, and electrolyte decomposition under high temperatures or voltages. Enhanced mitigation strategies, encompassing electrolyte design, buffer layer construction, and electrode material optimization, are deliberated upon. Accordingly, subsequent research endeavors should prioritize long-term high-precision gas detection to bolster the safety and performance of SIBs, thereby fortifying their commercial viability and furnishing dependable solutions for large-scale energy storage and electric vehicles.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-024-01546-7
Sodium-ion batteries hold great promise as next-generation energy storage systems. However, the high instability of the electrode/electrolyte interphase during cycling has seriously hindered the development of SIBs. In particular, an unstable cathode–electrolyte interphase (CEI) leads to successive electrolyte side reactions, transition metal leaching and rapid capacity decay, which tends to be exacerbated under high-voltage conditions. Therefore, constructing dense and stable CEIs are crucial for high-performance SIBs. This work reports localized high-concentration electrolyte by incorporating a highly oxidation-resistant sulfolane solvent with non-solvent diluent 1H, 1H, 5H-octafluoropentyl-1, 1, 2, 2-tetrafluoroethyl ether, which exhibited excellent oxidative stability and was able to form thin, dense and homogeneous CEI. The excellent CEI enabled the O3-type layered oxide cathode NaNi1/3Mn1/3Fe1/3O2 (NaNMF) to achieve stable cycling, with a capacity retention of 79.48% after 300 cycles at 1 C and 81.15% after 400 cycles at 2 C with a high charging voltage of 4.2 V. In addition, its nonflammable nature enhances the safety of SIBs. This work provides a viable pathway for the application of sulfolane-based electrolytes on SIBs and the design of next-generation high-voltage electrolytes.