Development and characterization of laboratory-scale sodium-ion battery full cell containing low fluorinated electrolyte

Sodium-ion batteries (NIBs) are increasingly recognized as a viable and complementary technology to the Li-ion batteries (LIBs), with progress towards commercialization. However, the performance, stability and safety of these devices need to be further improved. State-of-the-art electrolytes, containing high fluorine content such as sodium hexafluorophosphate (NaPF$_6$), guarantee satisfactory performance with improved SEI stability, but they pose serious environmental and safety concerns. Therefore, the development of less-fluorinated electrolytes that offer safe, sustainable, and promising performance is immensely important. This study investigates a sustainable, low-fluorinated electrolyte, comprising sodium bis(fluorosulfonyl)imide (NaFSI) and sodium difluoro(oxalato)borate (NaDFOB) in propylene carbonate (PC) solvent, for NIBs. The findings underscore that the use of this electrolyte in a laboratory-scale NIB full cell containing hard carbon (HC) and P2-Na$_{2/3}$Al$_{1/9}$Fe$_{1/9}$Mn$_{2/3}$Ni$_{1/9}$O$_{2}$ (P2-AFMNO) cathode, allows the realization of devices which display high performance and stability, i.e., achieving 80 % capacity retention within a wider voltage range of 1.5–4.3 V vs Na$^+$/Na, after 200 cycles. ... mehrAn X-ray photoelectron spectroscopy (XPS) analysis revealed the formation of inorganic-rich, robust and stable interfaces on both electrodes, contributing to enhanced stability and lifetime of the NIB demonstrator.