Electrochemistry (Jul 2023)

Application of Modified Styrene-Acrylic-Rubber-based Latex Binder to LiCoO2 Composite Electrodes for Lithium-ion Batteries

  • Lu YIN,
  • Ryoichi TATARA,
  • Shogo YAMAZAKI,
  • Rena TAKAISHI,
  • Eisuke SHIIYAMA,
  • Takashi MATSUYAMA,
  • Satoshi YASUNO,
  • Shinichi KOMABA

DOI
https://doi.org/10.5796/electrochemistry.23-00048
Journal volume & issue
Vol. 91, no. 7
pp. 077005 – 077005

Abstract

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A new combination of styrene acrylic rubber (SAR) and sodium carboxymethylcellulose was developed as a water-borne binder for LiCoO2 composite electrodes operating at high voltages. Four novel SAR-based latex binders were synthesized with butyl acrylate or 2-ethylhexyl acrylate monomer and styrene via copolymerization with low and high crosslinking degrees. Composite electrodes prepared using lower-crosslinking-degree SAR binders became more stretchable and flexible. Surface analysis using electron microscopy and X-ray photoelectron spectroscopy revealed that the cycled LiCoO2 electrode was covered with approximately 10-nanometer-thick decomposition products when a conventional poly(vinylidene fluoride) binder was used. The electrodes with SAR-based binders with low cross-linkage formed a stable passivation surface during the initial cycle, and further continuous electrolyte decomposition was successfully suppressed. This passivation improved the cycle stability of LiCoO2 electrode up to 4.5 V, i.e., 87.1 % capacity retention, even after 100 cycles and suppressed self-discharge performance at 45 °C.

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