The role of anions, solvent molecules and solvated electrons in layer formation processes on anode materials for rechargeable lithium batteries

The reactivity of anions, solvent molecules and solvated electrons against anode materials are coupled in a given electrolyte solution. The ratio between anion and solvent decomposition depends on the potential and the electrolyte composition. The life time of trapped solvated electrons within the growing SEI layer depends on the donor-acceptor properties of the incorporated solvent molecules and is in the range among 3-10 s. The places of the trapped electrons are the origin of 'metallic' lithium clusters within the forming layer. Their growth will lead to the well-known lithium dendrites on lithium-metal or the progressive irreversible capacity loss on lithium-carbons and therefore causes a lot of problems. Suggestions will be made how to solve these problems in order to achieve a homogeneous SEI with a reduced dendrite growth or decreased irreversible capacity loss. (C) 1999 Elsevier Science S.A. All rights reserved.