Abstract
Silicon is a very promising anode material for Li-ion batteries due to its much higher storage capacity than graphite [1]. However, its huge volume expansion upon lithiation induces major mechanical degradation of the electrode, resulting in a poor cycle life. In this context, the optimization of the binder properties used for the electrode processing is crucial. In the present work, the impact of the addition of metallic ions (e.g. Zn2+) in the electrode formulation, likely to chemically crosslink carboxylate groups of the binder (e.g. carboxymethyl cellulose) is studied. The formation of COO-metal coordination bonds is confirmed from IR spectroscopy analyses and its impact on the rheological properties of the ink, the mechanical strength of the coating and the electrochemical performance of the electrode is highlighted. This approach, with the myriad of possibilities of coordination chemistry, opens very interesting prospects for designing a novel class of smart binders for lithium-ion batteries.
[1] M.N. Obrovac, V.L. Chevrier, Alloy Negative Electrodes for Li-Ion Batteries. Chem. Rev. 2014, 114, 11444-11502.