Higher demands have been placed on the power system of near-space missions due to the low-temperature environment. Lithium-ion batteries (LIBs), the primary power source for space systems, have significant technical obstacles to normal operation in harsh environments due to their rapid capacity deterioration and eventual battery failure at below-freezing temperatures. E For LIBs to function at low temperatures, electrolyte—including bulk electrolyte and solid electrolyte interface (SEI) film—is essential. Therefore, the development of advanced electrolyte for low-temperature conditions is important for the operation of LIBs in extremely cold environments. The design status of the low-temperature electrolyte of LIBs for near-space vehicles was evaluated, along with a summary of pertinent strategies to improve the LIBs of electrolyte for low-temperature conditions, with the goal of identifying the factors limiting the low-temperature performance of LIBs. This work provides a feasible strategy for the development of Energy storage equipment in near-space vehicles.

Sodium-ion batteries are strong candidates for secondary batteries for near-space vehicles. Although there aren’t many reports, the monitoring, failure, and mechanism of sodium plating in hard carbon anodes provide guidelines for the use and management of sodium-ion batteries. For this, a trustworthy understanding of the sodium plating behavior of hard carbons is provided by setting a series of sodium precipitation gradients, using differential capacity curves, combined with scanning electron microscopy (SEM) and galvanostatic intermittent titration technique (GITT). The results show that sodium clusters appear on the surface of the hard carbon at a current density of 20 mA/g for 12.5 h. The sodium clusters are converted into sodium-metal by continuing to sodiate for 2.5 h and the voltage of desodiation of the sodium-metal can be detected by the differential capacity curves. The battery’s cycling performance is not impacted by the sodium clusters because of their low formation energy; however, the sodium-metal causes an increase in the battery’s interfacial impedance and charge transfer impedance, which accelerates the degradation of the battery’s cycling performance.

As a carbon resource with abundant nitrogen, polyacrylonitrile (PAN) has been used for the key raw materials to produce carbon materials. However, the direct carbonization will lead to the cementation of PAN particles, which is adverse to the subsequent activation. In this work, a hybrid porous carbon (HPC) was synthesized via dry ball-milling of thermal-reduced graphene and polyacrylonitrile, and subsequent stabilization and KOH activation. The effect of the ratio of graphene and polyacrylonitrile, along with activation treatment on the properties of hybrid porous carbon are systematically studied. The results demonstrate that the existence of graphene nanosheets enable the fast dissipation of heat produced in ball-milling process and avoid the cementation of PAN particles, while PAN particles act as spacers to prevent graphene restacking. The as-obtained polyacrylonitrile/graphene precursor is a loose powder, which favors the dispersion of activation agents within the precursor and results in a more homogeneous and effective activation. Meanwhile, graphene works as a 3D micro-current collector, thus providing a conductive network for convenient charge transfer in HPC. Based on the electrochemical characterization in either water or a non-aqueous electrolyte, HPC exhibits a superior capacitive behavior because of its well-developed porosity, large specific surface area, excellent electrical conductivity as well as nitrogen/oxygen heteroatom induced pseudo-capacitance. Particularly, HPC-4 offers a high energy density of 30.38 W·h/kg at a power density of 337.5 W/kg in TEABF4/EC-DMC electrolyte. This work provides an easy-to-operate and efficient synthesis strategy for developing porous carbon electrode towards supercapacitors with high power and energy density.