Enhanced intercalation behaviors of edge-rich flakes-stacked graphite for Al-graphite dual-ion battery

Abstract

Graphite has been almost proven to be the positive material with the highest voltage and superior cycle stability for Al-graphite dual-ion battery. However, the limited energy density of graphite as positive material still blocks the future practical application. It is of great significance to further improve the energy density of the battery to satisfy the growing demand. In this regard, an edge-rich flakes-stacked graphite prepared by intentionally eroding the outer dense graphitic layer of graphite paper is demonstrated to apply in Al-graphite dual-ion battery that the chloroaluminate anions can be directly transported from edge-rich graphene nanoflakes and diffused into interior graphitic layers, which will greatly shorten the diffusion pathway, thus revealing better rate capability. The edge-rich flakes-stacked graphite paper enables to deliver a reversible capacity of ~87 mAh g−1 at 50 mA g−1, significantly higher than that of the untreated graphite paper electrode. More importantly, owing to the ultrahigh areal mass loading advantage, the as-assembled batteries exhibit much enhanced areal capacity (1.2 mAh cm−2), which is distinctly the highest among the reported graphite-based electrodes.