Designing In-Situ-Formed Interphases Enables Highly Reversible Cobalt-Free LiNiO_2 Cathode for Li-ion and Li-metal Batteries

摘要

Cathode materials control both the energy density and cost of Li-ion and Li-metal batteries. The cobalt-free LiNiO_2 with relatively low cost and extremely high theoretical energy density (～1,050 Wh kg ~1) is one of the most promising cathode materialsfor high-energy batteries. However, the continuous Ni dissolution, structural disordering, particle cracking, and unstable cathode electrolyte interphase (CEI) hinder its applications. Here, we surmount these challenges by forming a robust fluoride (F)- and boron (B)-rich CEI on LiNiO_2 using a high-fluorinated electrolyte with LiDFOB additive. The LiNiO_2 cathode maintains an unprece-dentedly high capacity retention of >80% after 400 deep cycles at a high charge cut-off voltage of 4.4 V (versus Li/Li~+). In addition, the electrolyte forms an F-and B-rich interphase on the Li metal and graphite anodes, allowing stable cycling of full cells. This work sheds light on designing interracial chemistry for high-energy cathodes, and its principle is applicable for other alkali metal ion cathodes.