Dual application of non-fluorinated polymer: Influence on mitigating dendrite growth and structural integrity of high energy density lithium metal battery

Fluorine-based polyvinylidene difluoride is one of the most widely used binders for Lithium-ion batteries due to good thermal and electrochemical stability. However, PVDF has several significant disadvantages, which could greatly restrict its practical application. PVDF is not suitable for Lithium metal batteries with cutting-edge cathode materials and lithium metal anode because of the swelling and degradation of electrode particles as well as unstable solid electrolyte interface on the Lithium anode in liquid electrolytes at elevated temperatures. Herein, the non-fluorinated polymer of Poly-1-Vinyl-2-pyrrolidinone-crosslinked-prop-2-enoic acid is developed as both binders for Ni-rich LiNi0.8Mn0.1Co0.1O2 cathode and artificial SEI layer for stable lithium-metal anodes, enabling all Li metal batteries, with excellent mechanical integrity. As a binder, Ni-rich NMC cathode (LiNi0.8Mn0.1Co0.1O2) displays an initial discharging capacity of 232.6 mAh g−1 with Coulombic efficiency of nearly 89.9 % compared to PVDF (77.6 %). It also demonstrated good cycling stability even after 200 cycles by exhibiting a 146.2 mAh g−1 discharging capacity at a 1C rate with 92 % capacity retention. In addition, Li/Poly-VPCPEA@PP/Li symmetric cell revealed a low voltage hysteresis of 10 mV over 1000 h for 1 mA cm2 and 200 h for 5 mA cm−2. A dipolar functional group-containing 3D network of Poly-1-Vinyl-2-pyrrolidinone-crosslinked-prop-2-enoic acid Poly-(VPCPEA) aqueous binder in the LiNi0.8Mn0.1Co0.1O2 (NMC-811) electrode, which can effectively improve the mechanical integrity and adhesive strength of the cathode in lithium-metal batteries. In addition, a Poly-(VPCPEA) coated layer on a PP separator with huge functional groups is an effective strategy for suppressing the growth of Li dendrites and irreversible side reactions, and the structural stability of the both electrodes. [Display omitted] •For the Lithium metal battery, a non-fluorinated poly-(VPCPEA) binder is used.•The initial reversible capacity efficiency of Li-NMC cells with the Poly-(VPCPEA) binder was 89.9%.•Li-NMC cell with the Poly-(VPCPEA) binder capacity retention was 92% after 200 cycles even at a high current density of 1C•Li-Li cell test results, exhibited a steady voltage profile over 1000 h without significant voltage changes.