Novel silane-treated polyacrylonitrile as a promising negative electrode binder for LIBs

With the rapid increment of the electric vehicle market, silicon has attracted tremendous attention as a promising anode material for lithium-ion batteries (LIB) due to its tenfold higher gravimetrical energy density compared with a traditional graphite anode. To eliminate the well-known poor cycle life issue originated from the large volume expansion of the silicon-based electrode, the development of novel polymeric binder is essential. Herein, we synthesized a novel silane-treated polyacrylonitrile (Si-PAN) as an anode binder using facile azide-nitrile click reaction. Incorporation of silane to the cyclized-PAN structure enhances affinity between the electrode components and a current collector because it has organic and inorganic moiety simultaneously in polymeric backbone. This work implements a Si-alloy (Si₇₀Ni₂₀Cu₁₀) based electrode with improved capacity retention through the optimization of silane amount and thermal treatment condition. Namely, the electrode composing Si-treated PAN-2.0 binder and Si-alloy, after being thermally treated at 450 °C shows stable discharge capacity of 760 mA h g⁻¹ upon 50 cycles, resulting in 46% capacity retention improvement against pristine PAN binder (at 450 °C). New binder demonstrates a great potential to improve the electrochemical properties of next-generation electrode materials for energy storage systems.