Microporous ceramic coated separators with superior wettability for enhancing the electrochemical performance of sodium-ion batteries

Nature-Derived Cellulose-Based Composite Separator for Sodium-Ion Batteries

“…Because the electrolyte uptake ability directly affects the ionic conductivity of electrolyte soaked in separator and electrochemical properties, the ionic conductivity and Na + transfer value were subsequently evaluated. The ionic conductivity of electrolyte-soaked separator presented 0.751 mS cm −1 (cellulose-PAN-Al 2 O 3 composite separator) and 0.686 mS cm −1 (cellulose-PAN separator) as shown in Figure 3D, which were lower than the ionic conductivity of GF separator (3.215) (Suharto et al, 2018). In addition, the sodium ion transfer number (t + Na ) was significantly improved for the cellulose-PAN-Al 2 O 3 composite separator (t + Na = 0.78) compared with that of the cellulose-PAN separator (t + Na = 0.31) ( Figures 3E,F).…”

“…However, one shortcoming of SIBs is the slightly higher standard electrode potential of sodium [−2.7 V vs. the standard hydrogen electrode (SHE)] relative to that of lithium (−3.04 V vs. SHE), which has motivated the development of high-energy-density cathode materials and high-capacity anode materials (Yabuuchi et al, 2012(Yabuuchi et al, , 2013Guignard et al, 2013;Vassilaras et al, 2013). There have been many reports on high-energy-density cathode materials with surface modification to prevent particle damage from the changing volume during charge/discharge, anode materials with high reversible capacity, and stable electrolytes under oxidizing environments (Yu et al, 2015;Hwang et al, 2017;Åvall et al, 2018;Kim et al, 2018;Sato et al, 2018;Suharto et al, 2018;Choi et al, 2019;Jo et al, 2019;Lee et al, 2019;Wang et al, 2020). In most of these studies, glass fibers (GF) have been widely used in most SIBs because of their advantages over excellent wettability for ethylene carbonate and propylene carbonate, indicating high porosity (66%), large electrolyte uptake (360%), high ionic conductivity of electrolyte soaked in separator (3.8 mS cm −1 ), sodium ion transfer number (t + Na = 0.79) than polypropylene membrane (Zhu et al, 2016;Arunkumar et al, 2019).…”

“…Separators must provide adequate (1) porosity, (2) wettability, (3) chemical and thermal stability, and (4) ionic conductivity of electrolyte soaked in separator. Polypropylene (PP) and polyethylene (PE) separators are not suitable as a separator for batteries, because the separators exhibit very low wettability for cyclic carbonate-based electrolytes such as ethylene carbonate (EC) and propylene carbonate (PC), which are used as electrolytes for SIBs (Suharto et al, 2018). Their low thermal property is considered as another difficulty to apply them for SIBs (Xu, 2004;Kim et al, 2014;Zhu et al, 2016).…”

“…Herein, we propose a new cellulose-polyacrylonitrile-alumina composite as a SIB separator (Scheme 1). Cellulose nanofibers are easily obtained from plants and are composed of closepacked polysaccharide chains with β-(1 → 4) -D-glucopyranose repeating units (Siró and Plackett, 2010). Cellulose nanofibers provide advantages in the process of separating membranes owing to their excellent dispersing properties in various solvents and inherent porous nanostructure, good thermal stability (melting point ≥ 250 • C), hydrophilicity, and chemical stability (Chun et al, 2011).…”

Influence of Separator Material on Infiltration Rate and Wetting Behavior of Lithium‐Ion Batteries

“…Due to the high number of oxidic functional groups at the surface of these particles, a hybrid separator is more hydrophilic than a comparable polyolefinic material. Therefore, the contact angle is dramatically reduced when a typical hydrophilic electrolyte is used. This effect can be extended by adding surfactants to the electrolyte solution.…”