Full-cell Cycling of Self-supporting Aluminum Foil Anode with Phosphate Conversion Coating

ABSTRACT: Aluminum foil should be a promising candidate anode material for lithium ion batteries (LIBs), considering its high theoretical capacity, low lithiation voltage and abundance. However, as a matter of fact, it has been a great challenge to make Al foil cycle in full cells at industrially acceptable areal capacity like 2 – 4 mAh/cm2 for commercial 18650 LIBs and some high-power LIBs. In this study, we defined the concepts of electrochemical true contact area (ECA) (areas with perfect electrolyte/electrode contact) and electrochemical noncontact area (ENA) (referred to regions without electrolyte spread on) for the metal foil anode. An initial ECA/ENA partition would cause severe inhomogeneity of the alloying reaction, cause localized electrode pulverization, and exacerbate ECA/ENA inequality even more. Through a phosphate conversion coating on aluminum foil, we killed two birds with one stone: firstly, the Al foil with phosphate conversion coating has improved wettability (characterized by contact...