Synthesis and Characterization of Von Alpen-Type Nasicon Ceramic and Its Application to Rechargeable Seawater Battery

摘要

Rechargeable seawater battery (SWB), which utilizes naturally abundant seawater as its cathode, is having attention for a next-generation large-scale energy storage system (ESS) due to its low cost and eco-friendliness. For an effective Na~+ transfer solid electrolyte for SWB, Hong-type NASICON (Na_3Zr_2Si_2PO_(12)) ceramic has been used because of its known high Na-ion conductivity (～3×10~(-4) S/cm). However, the SWB coin cell test showed that the Hong-type NASICON ceramic accounts for 62% (132Ω) of the total cell resistance (214Ω). This has been considered as one of major drawbacks for developments of SWB technology. Hence, it has been requested to achieve higher ionic conductivity of Na-ion conducting ceramics, increasing power of the current SWB by reducing its cell ohmic resistance.