Time Release of Encapsulated Additives for Enhanced Performance of Lithium-Ion Batteries

Tae Wook Lim, Chan Woo Park, Scott R. White, Nancy R. Sottos

Research output: Contribution to journalArticle

Abstract

Time release of encapsulated vinylene carbonate (VC) from microcapsules in Li-ion batteries is demonstrated to enhance the rate performance without sacrificing capacity retention. VC-filled microcapsules are successfully prepared by the solvent exchange method that allows VC to diffuse through the microcapsule shell wall at an elevated temperature. The concentration of VC added directly to the electrolyte in a pouch cell (2 wt %) significantly decreases after the first cycle at C/10-rate. In pouch cells that contain 5 wt % VC-filled microcapsules, the concentration of VC increases from 0 to 3 wt % over the first cycle because of the diffusion of microencapsulated VC in the electrolyte. Electrochemical impedance spectroscopy, rate capability, and long-term cycling tests are conducted for pouch cells with VC additives (0, 2, and 5 wt %) and VC microcapsules (5 wt %). Pouch cells with both 5 wt % VC additive and microencapsulated VC show improved capacity retention over 400 cycles at 1 C-rate compared to the cells without VC additive. When VC is added directly, the high initial concentration leads to increased interfacial resistance and decreased rate capability. By contrast, time release of microencapsulated VC by diffusion through microcapsules increases the discharge capacity 2.5 times at 5 C-rate compared to the direct VC addition to the electrolyte.

Original languageEnglish (US)
Pages (from-to)40244-40251
Number of pages8
JournalACS Applied Materials and Interfaces
Volume9
Issue number46
DOIs
StatePublished - Nov 22 2017

Keywords

  • battery additives
  • lithium-ion batteries
  • microcapsules
  • time release
  • vinylene carbonate

ASJC Scopus subject areas

  • Materials Science(all)

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