These days most commercial separators for lithium-ion batteries are made of polyethylene (PE) and polypropylene (PP), or their combination. For some applications, the polyolefin-based separators exhibit good performances and provide an acceptable safety to avoid short circuits by their intrinsic thermal shutdown ability. Nevertheless, the major limitation of these polyolefin-based separator membranes is their narrow safety margin for the transversal and horizontal shrinkage at high temperatures, up to 160°C when the battery is under overcharge, and poor wettability by the electrolyte. In order to improve these issues, ceramic particles, such as SiO2, AI2O3, CaCO3, can be applied as a coating layer on top of polyolefin-based separators or mixed in a polymer dispersion forming a self-standing separator (1). This work presents an aqueous processing to prepare a membrane based on low cost and environmental friendly materials, such SiO2 as filler particles and hydroxypropylated guar gum (HPG) as polymeric binder. The prepared membrane is characterized regarding its temperature stability and electrochemically investigated as separator for lithium-ion batteries using lithium nickel-manganese-cobalt oxide (LiNi_(1/3)Mn_(1/3)Co_(1/3)O2 or NMC) and lithium titanate oxide (Li4Ti5O_(12) or LTO) as active materials.
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