The role of mechanically induced separator creep in lithium-ion battery capacity fade

Christina Peabody, Craig B. Arnold

Research output: Contribution to journalArticlepeer-review

194 Scopus citations


Lithium-ion batteries are well-known to be plagued by a gradual loss of capacity and power which occur regardless of use and can be limiting factors in the development of emerging energy technologies. Here we show that separator deformation in response to mechanical stimuli that arise under normal operation and storage conditions, such as external stresses on the battery stack or electrode expansion associated with lithium insertion/deinsertion, leads to increased internal resistance and significant capacity fade. We find this mechanically induced capacity fade to be a result of viscoelastic creep in the electrochemically inactive separator which reduces ion transport via a pore closure mechanism. By applying compressive stress on the battery structure we are able to accelerate aging studies and identify this unexpected, but important and fundamental link between mechanical properties and electrochemical performance. Furthermore, by making simple modifications to the electrode structure or separator properties, these effects can be mitigated, providing a pathway for improved battery performance.

Original languageEnglish (US)
Pages (from-to)8147-8153
Number of pages7
JournalJournal of Power Sources
Issue number19
StatePublished - Oct 1 2011

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering


  • Aging
  • Capacity fade
  • Lithium-ion battery
  • Mechanical stress
  • Polymer separator
  • Power fade


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