Modification of NASICON Electrolyte and Its Application in Real Na-Ion Cells

• 作者: Qiangqiang Zhang Quan Zhou Yaxiang Lu Yuanjun Shao Yuruo Qi Xingguo Qi Guiming Zhong Yong Yang Liquan Chen Yong-Sheng Hu
• 来源期刊: 工程（英文）
• 年，卷（期）: 2022,（1）
• 所属期刊栏目: Solid-State Batteries-Article
• 页码范围: 170-180
• 页数: 11页
• 语种: 英文

摘要

The low ionic conductivity of solid-state electrolytes(SSEs)and the inferior interfacial reliability between SSEs and solid-state electrodes are two urgent challenges hindering the application of solid-state sodium batteries(SSSBs).Herein,sodium(Na)super ionic conductor(NASICON)-type SSEs with a nominal com-position of Na3+2xZr2-xMgxSi2PO12 were synthesized using a facile two-step solid-state method,among which Na3.3Zr1.85Mg0.15Si2PO12(x=0.15,NZSP-Mg0.15)showed the highest ionic conductivity of 3.54mS·cm-1 at 25℃.By means of a thorough investigation,it was verified that the composition of the grain boundary plays a crucial role in determining the total ionic conductivity of NASICON.Furthermore,due to a lack of examination in the literature regarding whether NASICON can provide enough anodic electrochemical stability to enable high-voltage SSSBs,we first adopted a high-voltage Na3(VOPO4)2F(NVOPF)cathode to verify its compatibility with the optimized NZSP-Mg0.15 SSE.By com-paring the electrochemical performance of cells with different configurations(low-voltage cathode vs high-voltage cathode,liquid electrolytes vs SSEs),along with an X-ray photoelectron spectroscopy eval-uation of the after-cycled NZSP-Mg0.15,it was demonstrated that the NASICON SSEs are not stable enough under high voltage,suggesting the importance of investigating the interface between the NASICON SSEs and high-voltage cathodes.Furthermore,by coating NZSP-Mg0.15 NASICON powder onto a polyethylene(PE)separator(PE@NASICON),a 2.42 A·h non-aqueous Na-ion cell of carbon|PE@NASICON|NaNi2/9Cu1/9Fe1/3Mn1/3O2 was found to deliver an excellent cycling performance with an 88％capacity retention after 2000 cycles,thereby demonstrating the high reliability of SSEs with NASICON-coated separator.