A sandwich structure polymer/polymer-ceramics/polymer gel electrolytes for the safe, stable cycling of lithium metal batteries

Abstract The highest specific capacity (3860 mAh g−1) and minimum negative electrochemical potential make lithium metal as a perfect candidate for next-generation high energy battery. However, the safety issue caused by the lithium dendrite growth hinders the practical use of lithium metal battery. Herein, a polymer/polymer-ceramic/polymer sandwich structure electrolytes (SWEs) are proposed to address this problem by combing the advantage of inorganic and gel-type polymer electrolytes. The flexible SWEs show a high ionic conductivity (~3.01 ×10−3 S/cm) at room temperature, high lithium transference number (tLi+ = 0.74), and stable electrochemical widows up to 5.0 V. Furthermore, the SWEs can effectively prevent lithium dendrites in a symmetric Li/SWEs/Li test during charge and discharge with a current density of 1 mA/cm2 for 240 h at room temperature. Meanwhile, the lithium metal battery assembled using LiCoO2/SWEs/Li exhibits the high cycling capacity of ~ 110 mAh g−1 at 2 C over 100 cycles and fascinating rate performance (144 mAh g−1@ 1 C and 98 mAh g−1@ 5 C) at room temperature. Our work provides a new design paradigm to exploit the advanced electrolyte for lithium metal battery and flexible devices.