Delpuech Nathalie, Dupre Nicolas, Moreau Philippe, Bridel Jean-Sebastian, Gaubicher Joel, Lestriez Bernard, Guyomard Dominique
Institut des Matériaux Jean Rouxel, IMN, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322, Nantes Cedex 3, France.
Umicore Group Research & Development, Kasteelstraat 7, Olen, Belgium.
ChemSusChem. 2016 Apr 21;9(8):841-8. doi: 10.1002/cssc.201501628. Epub 2016 Feb 24.
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 LiCoO2 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.
了解锂离子电池硅基负极在循环过程中的老化机制对于解决库仑效率低和容量衰减问题至关重要，进而在商业电池中应用这种新型高容量材料。然而，迄今为止，此类研究主要集中在半电池上，其中硅与无限锂源进行循环。在本工作中，研究了以LiCoO₂为正极的全锂离子电池配置下硅基电极在循环过程中的老化机制。对两个电极的死后分析清楚地表明，它们都不含有锂，并且循环过程中没有明显的降解。老化机制可以用溶剂分子的还原来解释。从正极提取的电子导致电池内部失衡，这导致电极逐渐滑动，并减少了两个电极可循环锂离子的组成范围。
