An insight into failure mechanism of NASICON-structured Na3V2（PO4）3 in hybrid aqueous rechargeable battery

NASICON (Na-super-ionic-conductors)-structured materials have attracted extensive research interest due to their great application potential in secondary batteries. However, the mechanism of capacity fading for NASICON-structured electrode materials has been rarely studied. In this paper, we synthesized the NASICON-structured Na3V2(PO4)3/C composite by simple sol-gel and high-temperature solid-phase method and investigated its electrochemical performance in Na-Zn hybrid aqueous rechargeable batteries. After characterizing the structure, morphology and composition variations as well as the interfacial resistance changes of Na3V2(PO4)3/C cathode during cycling, we propose a mechanical and interfacial degradation mechanism for capacity fading of NASICON-structured Na3V2(PO4)3/C in Na-Zn hybrid aqueous rechargeable batteries. This work will shed light on enhancing the mechanical and in terfacial stability of NASICON-structured Na3V2(PO4)3/C in Na-Zn hybrid aqueous rechargeable batteries.

Optimization on transport of charge carriers in cathode of sulfide electrolyte-based solid-state lithium-sulfur batteries

Lithium-sulfur(Li-S)batteries are considered as promising candidates for novel energy storage technology that achieves energy density of 500 Wh·kg^(−1).However,poor cycle stability resulting from notorious shuttle effect and the safety concerns deriving from flammability of ether-based electrolyte hinder the practical application of Li-S batteries.Because of low solubility to polysulfide,high ionic conductivity,and safety property,sulfide-based electrolytes can fundamentally address above issues.It is widely known that the effective transports of both electrons and ions are basic requirement for redox reaction of active materials in cathode.Thereby,construction of fast and stable ionic and electronic transport paths in cathode is especially pivotal for cycle stability of solid-state Li-S batteries(SSLSBs).In this review,we provide research progresses on facilitating transport of charge carriers in composite cathode of SSLSBs.From perspective of materials,intrinsically conductivity of electrolyte and carbon shows dramatic effect on migration of charge carriers in cathode of SSLSBs,thereby the conductive additives are summarized in the manuscript.Additionally,the charge transport in cathode of SSLSBs fully depends on the physical contact between active materials and conductive additives,therefore we summarized the strategies optimizing interfacial contact and reducing interfacial resistance.Finally,potential future research directions and prospects for SSLSBs with improved energy density and cycle performance are also proposed.