Dilation Study of Si-Rich Anode in the Next Generation Lithium-Ion Batteries

Abstract

Silicon has attracted a lot of attention as anode material in lithium ion batteries due to its high practical capacity (around 3579 mAh.g-1 at Li15Si4 phase [1]). The main drawback for the use of Silicon is its significant volume expansion around 300% in fully intercalate state which causes particles pulverisation, dynamic formation of the solid electrolyte interface (SEI), losing electrical contact and capacity loss.[2] The solution is hidden in using silicon composite instead of pure silicon, [1,3] applying partial lithiation or delithiation process,[4] and improving the electrical particles contact by applying optimum external pressure.[5] The main aim of the current study is to investigate the electrochemical performance and the dilatometry behaviour of a multilayer pouch cells (0.06 to 1.5 Ah) under the external mechanical pressure. Using 1/3 of the Si capacity in order to stabilized electrochemical performance of a highly content silicon anodes (70 wt% Si), exhibited electrode irreversible expansion around 20% after 3 cycles of formation at 0.1C and 75% electrode thickening after 200 cycles at 0.5C.