Studies on Composite Solid Electrolytes with a Dual Selective Confinement Interface Structure of Anions for High-Performance Lithium Metal Batteries.

Solid-state lithium batteries (SSLBs) have attracted much attention due to their good thermal stability and high energy density. However, solid-state electrolytes with low conductivity and prominent interfacial issues have hindered the further development of SSLBs. In this research, inspired from a selective confinement structure of anions, a novel HMOF-DNSE composite solid electrolyte with a dual selective confinement interface structure is proposed based on the semi-interpenetrating structure generated by poly(vinylidene fluoride)-hexafluoropropylene (PVDF-HFP), poly(di--butylmethylammonium) bis(trifluoromethanesulfonyl)imide (PDADMATFSI), and a metal-organic frameworks MOF derivative (HMOF) as a filler. The dual-network structure of PVDF-HFP/PDADMATFSI combined with HMOF formed a dual selective confinement interface structure to confine out the movement of large anions TFSI, thereby enhancing the transfer ability of Li. Subsequently, the addition of HMOF further improves the transfer of Li by binding up TFSI through its crystal structure. The results show that HMOF-DNSE possesses a high room-temperature ionic conductivity (0.7 mS cm), a wide electrochemical window (up to 4.5 V), and a high Li transfer number () (0.56). LiFePO/HMOF-DNSE/Li cell shows an excellent capacity of 141.5 mAh g at 1C rate under room temperature, with a high retention of 80.1% after 500 cycles. The material design strategy, which is based on selective confinement interface structures of anions, offers valuable insights into enhancing the electrochemical performance of solid-state lithium batteries.