A High‐Performance Monolithic Solid‐State Sodium Battery with Ca2+ Doped Na3Zr2Si2PO12 Electrolyte

• Published in: Advanced energy materials 2019-07, Vol.9 (28), p.n/a
• Main Authors: Lu, Yao, Alonso, Jose A., Yi, Qiang, Lu, Liang, Wang, Zhong Lin, Sun, Chunwen
• Format: Article
• Language: English
• Subjects: 3D framework; Anodes; Anodic polarization; Architecture; Calcium ions; Electrode polarization; Electrolytes; Energy storage; Flux density; interfacial resistance; Ion currents; Low conductivity; monolithic architecture; Sodium; sodium batteries; Sol-gel processes; Solid electrolytes; solid‐state electrolytes; Storage batteries
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.201901205

Solid‐state sodium batteries (SSSBs) are promising electrochemical energy storage devices due to their high energy density, high safety, and abundant resource of sodium. However, low conductivity of solid electrolyte as well as high interfacial resistance between electrolyte and electrodes are two main challenges for practical application. To address these issues, pure phase Na3Zr2Si2PO12 (NZSP) materials with Ca2+ substitution for Zr4+ are synthesized by a sol‐gel method. It shows a high ionic conductivity of more than 10−3 S cm−1 at 25 °C. Moreover, a robust SSSB is developed by integrating sodium metal anodes into NZSP‐type monolithic architecture, forming a 3D electronic and ionic conducting network. The interfacial resistance is remarkably reduced and the monolithic symmetric cell displays stable sodium platting/striping cycles with low polarization for over 600 h. Furthermore, by combining sodium metal anode with Na3V2(PO4)3 cathode, an SSSB is demonstrated with high rate capability and excellent cyclability. After 450 cycles, the capacity of the cell is still kept at 94.9 mAh g−1 at 1 C. This unique design of monolithic electrolyte architecture provides a promising strategy toward realizing high‐performance SSSBs. A high performance monolithic all solid‐state sodium battery is designed by integrating a 3D Ca‐doped Na3Zr2Si2PO12 electrolyte with sodium metal anode. It is found that the artificial sodiophilic surface and 3D ion‐conductive framework enable tight interface contact and large contact area, leading to the ultralow interfacial resistance. This unique approach is promising for advanced solid‐state sodium batteries.