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Mechanism of Silicon Electrode Aging upon Cycling in Full Lithium‐Ion Batteries
Author(s) -
Delpuech Nathalie,
Dupre Nicolas,
Moreau Philippe,
Bridel JeanSebastian,
Gaubicher Joel,
Lestriez Bernard,
Guyomard Dominique
Publication year - 2016
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201501628
Subject(s) - electrode , lithium (medication) , silicon , faraday efficiency , materials science , cycling , ion , chemical engineering , nanotechnology , chemistry , optoelectronics , electrolyte , organic chemistry , medicine , archaeology , engineering , history , endocrinology
Understanding the aging mechanism of silicon‐based negative electrodes for lithium‐ion batteries upon cycling is essential to solve the problem of low coulombic efficiency and capacity fading and further to implement this new high‐capacity material in commercial cells. Nevertheless, such studies have so far focused on half cells in which silicon is cycled versus an infinite reservoir of lithium. In the present work, the aging mechanism of silicon‐based electrodes is studied upon cycling in a full Li‐ion cell configuration with LiCoO 2 as the positive electrode. Postmortem analyses of both electrodes clearly indicate that neither one of them contains lithium and that no discernible degradation results from the cycling. The aging mechanism can be explained by the reduction of solvent molecules. Electrons extracted from the positive electrode are responsible for an internal imbalance in the cell, which results in progressive slippage of the electrodes and reduces the compositional range of cyclable lithium ions for both electrodes.