Characteristics of sodium batteries using a layered P2-type, Na0.5Ni0.11Fe0.22Mn0.66O2 cathode and a nanostructured Sb-C anode in NaTFSI-PYR14TFSI electrolyte

Na-based storage systems working at room-temperature have recently gained the interest of the research community thanks to the large availability and low cost of sodium.[1,2] The real challenge in the sodium-based battery field is represented by the substitution of the extremely reactive metallic sodium anode that represents a serious issue to face in order to increase the intrinsic safety of the sodium cells. To further improve the safety level of sodium cells, we propose here the substitution of the more common organic-carbonate based electrolytes with an ionic liquid-based electrolyte characterized by higher thermal stability, lower volatility and non flammability.[4] We present here two electrode materials characterized by improved morphology and enhanced electrochemical behavior in terms of cycle stability and delivered capacity. A P2-type, Na0.5Ni0.11Fe0.22Mn0.66O2 transition metal layered oxide as cathode material and a nanostructured Sb-C alloying anode, have been studied in a 0.2m NaTFSI-PYR14TFSI electrolyte. The materials have been investigated through morphological analysis in order to get structural parameters and characteristics. Furthermore, electrochemical tests were performed to check the influence of the IL-based electrolyte in sodium cells.