Interfacial chemistry of vinylphenol-grafted PVDF binder ensuring compatible cathode interphase for lithium batteries

Abstract

Elevating operating voltage is an effective route to further promote the energy density of nickel-rich layered oxides based lithium batteries. However, high-voltage cycling generally incurs rapid capacity fade of cells due to severe decomposition of commercially available liquid electrolytes and active material degradation. Especially, reactive oxygen species including 1O2 generated under high-voltage cycling give rise to severe electrolyte decomposition and thus result in fast capacity fading of batteries. To address this issue, herein, we first develop a vinylphenol-grafted PVDF binder with 1O2-scavenging effect for nickel-rich layered oxide cathodes, which is inspired by the eliminating role of dopamine. Detailed experiment research demonstrates that the scavenging behavior of the as-developed binder can help induce compatible cathode/electrolyte interface. Resultantly, the as-developed binder endows LiNi0.6Co0.2Mn0.2O2/Li and LiNi0.8Co0.1Mn0.1O2/Li half cells with superior cycling stability, with capacity retentions of 80.53% after 200 cycles and 87.16% after 100 cycles at 0.5C under 3.0–4.5 V, respectively. This dopamine-inspired strategy with reactive oxygen-scavenging effect heralds an important paradigm for constructing compatible cathode/electrolyte interphase in various rechargeable lithium cells.