1,2,3-Tris (2-cyanoethoxy) propane (TPPN) as a new electrolyte additive has been investigated in 4.55 V high voltage lithium cobaltate (LiCoO₂) /graphite pouch cells. By comparing the cycle performance of cells without and with TPPN, it is found that the addition of TPPN can improve the performance, and the optimal weight proportion is 2%. At 3.00-4.55 V and 1C/1C, the cells with 2%TPPN has a capacity retention rate of 86.4% at 25℃ for 900 cycles compared with the capacity retention rate of 8.7% that without 2%TPPN. According to the theoretical calculation and linear sweep voltammetry, the decomposition of TPPN is preferred to that of the electrolyte solvent. It can be seen from N 1s spectra from X-ray photoelectron spectroscopy on LiCoO₂ surface that TPPN forms an interfacial film on the LiCoO₂ surface. It can be seen from the impedance data that the interface film formed by TPPN has low impedance and high stability. From theoretical calculation, scanning, transmission electron microscopy, X-ray diffraction on LiCoO₂ surface and Co 2p spectra from X-ray photoelectron spectroscopy on graphite surface, it is revealed that the interface film formed by TPPN can effectively suppress the decomposition of electrolyte and the dissolution of cobalt ions, confirming the high stability of the interface film formed by TPPN.

The sodium-iodine (Na-I) battery exhibits significant potential as an alternative energy storage device to the lithium-ion battery. However, its development is hindered by inadequate electrical and thermal stability, as well as the dissolution and shuttling of polyiodide. In this study, we report a preparation method for melamine carbon sponge (MC) via carbonizing a commercially available kitchen sponge. It was revealed that the as-prepared MC, composed of unique self-growing carbon nanotubes, could provide both physical and chemical adsorption capabilities for intermediate polyiodides to improve the electrochemical performance of NaI. Consequently, the NaI/MC electrode effectively minimized polyiodide dissolution and reduced the electrochemical impedance. The NaI/MC cathode demonstrated a high average discharge capacity of 92.75 mAh·g^–1 over 200 cycles while maintaining a coulombic efficiency of 94%. The research findings from our study have promising applications in Na-I batteries.