Batteries with an energy storage capacity of 280 Ah play a crucial role in promoting the development of smart grids. However, the inhomogeneity of their internal temperature cannot be accurately measured at different constant charge and discharge power, affecting the efficiency and safety of the battery. This work adopts finite element analysis to determine the typical internal temperature of a single-cell model, which can guide the measuring position of the battery. Before the manufacturing process, a slim pre-buried sensor is utilized to reduce the negative impacts of different constant charge and discharge powers. The maximum internal temperature of the battery is up to 77 °C at a constant charge and discharge power of 896 W. The temperature difference between the two poles and the battery surface is as high as 26.2 °C, which is beyond the safety temperature (55 °C). This phenomenon will result in the degradation of the positive electrode through dQ/dV curves. These measurements of battery internal temperature can improve battery heat control and facilitate the development of energy storage technology.

A biomass-derived aramid-ZrO₂ composite separator for Li-ion batteries has superior electrolyte wettability, thermal stability and ionic conductivity, enabling 128.2 mAh g⁻¹ discharge capacity (10C) and 93.5% energy retention after 1200 cycles.

Positive temperature coefficient (PTC) materials are pivotal for safeguarding lithium iron phosphate batteries, yet their industrial application is hindered by critical drawbacks: excessive film thickness, high internal resistance, and poor solvent sustainability. Addressing these challenges, this study innovatively develops a solvent-free thermal rolling process to fabricate an asymmetric expansion polymer film, specifically thermoplastic polyurethane (TPU) reinforced polyethylene (PE)/carbon composites, which significantly enhances the PTC effect. The core mechanism lies in the asymmetric thermal expansion of TPU and PE: this unique behavior disrupts the conductive carbon network, triggering a sharp PTC transition at around 120 °C. Further validation via an electrochemical-thermal coupling model confirms that the abrupt resistance increase effectively terminates battery discharge, a key safety function. The optimized composite (1% TPU-1% C@PE) exhibits exceptional performance: it features an ultrathin structure (8.5 μm) with low resistance (78 Ω) at room temperature, while reaching a high-resistance state (10 380 Ω) at 120 °C, achieving an impressive resistance ratio of 133.1. Notably, this performance is achieved without compromising the battery's cycling stability. The open circuit voltage of the 1% TPU-1% C@PE battery can quickly drop to 2.5 V within 570 s in an environment of 160 °C, due to the PTC effect. This work not only overcomes long-standing industrial bottlenecks but also provides a practical, scalable strategy, paving the way for advanced safety in lithium battery technology.

Developing cost-effective yet high-performance hard carbon anodes is critical for advancing the commercialization of sodium-ion batteries (SIBs), as they offer a balance of low cost, high capacity, and compatibility with Na⁺ storage mechanisms. Herein, waste towels, an abundant, low-cost precursor with a high carbon yield (>49%), were utilized to synthesize hard carbons via a two-step process: pre-oxidation at 250 °C to stabilize the fibrous structure, followed by carbonization at 1100 °C (THC-1100), 1300 °C (THC-1300), or 1500 °C (THC-1500). Electrochemical evaluations revealed that THC-1300, carbonized at an intermediate temperature, exhibited superior Na⁺ storage performance compared to its counterparts: it delivered a high reversible specific capacity of ~320 mAh/g at 1.0 C (1 C = 320 mA/g), with 78% capacity retention after 200 cycles, demonstrating excellent long-term cyclic stability. Its rate capability was equally impressive, achieving specific capacities of 341.5, 331.2, 302.0 and 234.8 mAh/g at 0.2, 0.5, 2.0 and 5.0 C, respectively, indicating efficient Na⁺ diffusion even at high current densities. Notably, THC-1300 also showed an improved initial Coulombic efficiency (ICE) of 75.4%, reflecting reduced irreversible Na⁺ consumption during the first cycle. These enhancements are attributed to the synergistic effects of THC-1300’s optimized structural and textural properties: a balanced interlayer spacing (d₍₀₀₂₎ = 0.387 nm) that facilitates rapid Na⁺ intercalation, a low BET surface area (1.62 m²/g) helps to minimize electrolyte side reactions. The combined advantages of high specific capacity, improved ICE, and remarkable cycling stability position this waste-towel-derived hard carbon as a highly viable and sustainable candidate for anode materials in next-generation SIBs, addressing both performance and cost requirements for large-scale energy storage applications.

Selective laser sintering (SLS) provides a promising route for the rapid fabrication of polymeric insulating components with complex geometries. However, its layer-by-layer manufacturing process inherently introduces structural anisotropy, which may significantly affect the electrical, thermal, and mechanical properties of the printed materials. In this study, polyamide 12 (PA12) specimens fabricated by SLS at different printing orientations were systematically investigated for dielectric properties, volume resistivity, DC and AC breakdown strength, tensile properties, and thermal conductivity. Scanning electron microscopy and X-ray microscopy were further employed to characterize the microstructure and clarify the origin of the anisotropic behavior. The results show that SLS-printed PA12 exhibits pronounced orientation-dependent properties. As the printing angle increases from 0° to 90°, the volume resistivity and DC breakdown strength generally decrease. In contrast, the relative permittivity generally increases with printing angle, whereas the AC breakdown strength and dielectric loss exhibit more complex non-monotonic variations. The tensile strength and elongation at break both gradually decrease with increasing printing angle. The thermal conductivity varies only slightly across different orientations but increases overall with printing angle. Microstructural observations reveal numerous interlayer pores, incompletely sintered regions, and heterogeneous interfaces with a distinct layered distribution. These heterogeneous interlayer structures affect the transport of charge, heat, and load, thereby contributing to the anisotropic electrical, thermal, and mechanical properties of SLS-printed PA12. These findings provide a basis for optimizing the printing orientation and structural design of SLS-printed PA12 for high-voltage insulation applications.