Sodium-ion hybrid capacitors (SICs), which combine the high energy density of batteries with the high power density and long cycle life of capacitors, are considered promising next-generation energy storage devices. Ensuring the performance of SICs in low-temperature environments is crucial for applications in high-altitude cold regions, where the desolvation process of Na⁺ and the transport process in the solid electrolyte interphase (SEI) are determinant. In this paper, we proposed a multi-ether modulation strategy to construct a solvation sheath with multi-ether participation by modulating the coordination of Na⁺ and solvents. This unique solvation sheath not only reduces the desolvation energy barrier of Na⁺, but more importantly forms a Na₂O-rich inorganic SEI and enhances the ionic dynamics of Na⁺. Benefiting from the excellent solvation structure design, SICs prepared with this electrolyte can achieve energy density of up to 178 Wh·kg^‒1 and ultra-high power density of 42390 W·kg^‒1 at room temperature. Notably, this SIC delivers record-high energy densities of 149 Wh·kg^‒1 and 119 Wh·kg^‒1 as well as power densities of up to 25 200 W·kg^‒1 and 24 591 W·kg^‒1 at ‒20 ℃ and ‒40 ℃, respectively. This work provides new ideas for the development of high-performance SICs for low-temperature operating environments.

As a critical role in battery systems, polymer binders have been shown to efficiently suppress the lithium polysulfide shuttling and accommodate volume changes in recent years. However, preparation processes and safety, as the key criterions for Li-S batteries’ practical applications, still attract less attention. Herein, an aqueous multifunction binder (named PEI-TIC) is prepared via an easy and fast epoxy-amine ring-opening reaction (10 min), which can not only give the sulfur cathode a stable mechanical property, a strong chemical adsorption and catalytic conversion ability, but also a fire safety improvement. The Li-S batteries based on the PEI-TIC binder display a high discharge capacity (1297.8 mAh g⁻¹), superior rate performance (823.0 mAh g⁻¹ at 2 C), and an ultralow capacity decay rate of 0.035% over more than 800 cycles. Even under 7.1 mg cm⁻² S-loaded, the PEI-TIC electrode can also achieve a high areal capacity of 7.2 mA h g⁻¹ and excellent cycling stability, confirming its application potential. Moreover, it is also noted that TG-FTIR test is performed for the first time to explore the flame-retardant mechanism of polymer binders. This work provides an economically and environmentally friendly binder for the practical application and inspires the exploration of the flame-retardant mechanism of all electrode components.

With the rapid development of flexible and portable microelectronics, the extreme demand for miniaturized, mechanically flexible, and integrated microsystems are strongly stimulated. Here, biomass-derived carbons (BDCs) are prepared by KOH activation using Qamgur precursor, exhibiting three-dimensional (3D) hierarchical porous structure. Benefiting from unobstructed 3D hierarchical porous structure, BDCs provide an excellent specific capacitance of 433 F g⁻¹ and prominent cyclability without capacitance degradation after 50000 cycles at 50 A g⁻¹. Furthermore, BDC-based planar micro-supercapacitors (MSCs) without metal collector, prepared by mask-assisted coating, exhibit outstanding areal-specific capacitance of 84 mF cm⁻² and areal energy density of 10.6 μWh cm⁻², exceeding most of the previous carbon-based MSCs. Impressively, the MSCs disclose extraordinary flexibility with capacitance retention of almost 100% under extreme bending state. More importantly, a flexible planar integrated system composed of the MSC and temperature sensor is assembled to efficiently monitor the temperature variation, providing a feasible route for flexible MSC-based functional micro-devices.