TY - JOUR AU - Ma, Qianli AU - Tsai, Chih-Long AU - Wei, Xian-Kui AU - Heggen, Marc AU - Tietz, Frank AU - Irvine, John T. S. TI - Room temperature demonstration of a sodium superionic conductor with grain conductivity in excess of 0.01 S cm −1 and its primary applications in symmetric battery cells JO - Journal of materials chemistry / A Materials for energy and sustainability A VL - 7 IS - 13 SN - 2050-7496 CY - London [u.a.] PB - RSC M1 - FZJ-2019-03329 SP - 7766 - 7776 PY - 2019 AB - The lack of suitable candidate electrolyte materials for practical application limits the development of all-solid-state Na-ion batteries. Na3+xZr2Si2+xP1−xO12 was the very first series of NASICONs discovered some 40 years ago; however, separation of bulk conductivity from total conductivity at room temperature is still problematic. It has been suggested that the effective Na-ion conductivity is ∼10−4 S cm−1 at room temperature for Na3+xZr2Si2+xP1−xO12 ceramics; however using a solution-assisted solid-state reaction for preparation of Na3+xZr2Si2+xP1−xO12, a total conductivity of 5 × 10−3 S cm−1 was achieved for Na3.4Zr2Si2.4P0.6O12 at 25 °C, higher than the values previously reported for polycrystalline Na-ion conductors. A bulk conductivity of 1.5 × 10−2 S cm−1 was revealed by high frequency impedance spectroscopy (up to 3 GHz) and verified by low temperature impedance spectroscopy (down to −100 °C) for Na3.4Zr2Si2.4P0.6O12 at 25 °C, indicating further the potential of increasing the related total conductivity. A Na/Na3.4Zr2Si2.4P0.6O12/Na symmetric cell showed low interface resistance and high cycling stability at room temperature. A full-ceramic cell was fabricated and tested at 28 °C with good cycling performance. LB - PUB:(DE-HGF)16 UR - <Go to ISI:>//WOS:000463819400048 DO - DOI:10.1039/C9TA00048H UR - https://juser.fz-juelich.de/record/863239 ER -