Polyphenylene sulfite based solid-state separator for blocking polysulfide in sodium-ion battery with cheap FeS anode

The anode material of sodium ion battery (SIB) as the focus of limiting its development has caused an intensive research on the SIB research field. Ferrous sulfide (FeS), as transition metal sulfide with high specific capacity and high tap density, is one of the potential anode materials for SIBs. However, its low electrical conductivity, large volume change, and inherent polysulfide shuttle issue present challenges for its practical application. Herein, we present a method for making carbon-coated ferrous sulfide ([email protected]) using a quick-freezing method to inhibit gel composition segregation. The FeS particles with high purity are uniformly encapsulated by the carbon layer, which improves its conductivity and stability. Moreover, a polyphenylene sulfide based solid state separator (PPS-SSS) with polyethylene (PE) anodic protection (PE-PPS-CSSS) is also introduced. And the tetrachlorobenzoquinone (TCBQ) is used to modify the PPS particles interface in the separator and adsorb the polysulfides to inhibit the shuttle of polysulfides and reduce the deactivited Na2S, which greatly improves the stability of the battery. The half-cell has an initial coulomb efficiency (CE) of ∼90% and a specific capacity of 360 mAh g−1. Meanwhile, a full cell with Na3V2(PO4)3 (NVP) and PE-PPS-CSSS has 81% capacity retention for 600 cycles at 1 C.