Xuesong Yin1,Liu Wang2,Guangyuan Wesley Zheng3
Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research)1,Zhengzhou University2,National University of Singapore3
Xuesong Yin1,Liu Wang2,Guangyuan Wesley Zheng3
Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research)1,Zhengzhou University2,National University of Singapore3
All-solid-state lithium-sulfur battery (ASSLSB) is a promising candidate for the post Li-ion battery technologies with high energy density and safety performance. However, the intrinsic insulating nature of sulfur requires triple-phase contact with ionic conductor and electronic conductor for electrochemical reactions, which lowers the active surface and charge-transfer efficiency. In this work, a double-phase interface constructed by mixed ionic/electronic conductor is proposed to enhance solid-state electrochemical reaction of sulfur. By employing lithium lanthanum titanium oxide (LLTO) nanofibers with mixed ionic/electronic conductivity, enhanced charge-transfer behavior is realized at the sulfur-LLTO double-phase interface, compared to the traditional triple-phase interface. As a result, high sulfur utilization (69%) and excellent rate performance (500 mAh/g at 1.0 C) are achieved. And the facilitated charge-transfer shows great potential to lower the operation temperature and improve the sulfur content for practical application of ASSLSBs. Cycle performance is also enhanced (850 mAh/g after 100 cycles at 0.2 C) due to the suppressed shuttle effect of polysulfides in PEO electrolyte by the LLTO nanofibers incorporation.