Selenium/Graphite Platelet Nanofiber Composite for Durable Li–Se Batteries

Long-lasting Li–Se cells with a Se/graphite platelet nanofiber (GPNF) composite is prepared for the first time, and it shows a reversible capacity of 489 and 384.7 mAh gSe–1 after 200 and 350 charge/discharge cycles, respectively. It shows superior rate capability and low Se polarization even with a high Se (75 wt %) proportion. It also shows higher capacity and better cycling stability compared to conventional Se/carbon material composites (with graphene oxide (GO), reduced GO, and carbon nanotubes). The effectiveness of GPNFs as a conductive support and for inhibiting the shuttle and dissolution of polyselenides in the electrolyte is also confirmed by conducting atomic force microscopy studies. Nanoscale current maps of Se/GPNFs reveal the presence of homogeneously distributed high-current domains, which are retained even after the first discharge. In contrast, the pristine Se electrode is characterized by predominant low-current regions after the first discharge. The ability of GPNFs to enable the preparation of durable and easily processable Li–Se cells is demonstrated.