Linking mechanical properties to electrochemical performance of silicon nanowires anodes in lithium ion batteries

New, higher capacity materials are required in order to address the fast growing need for greater energy density, longer cycle life and safer high-power operation batteries for both mobile and vehicle applications.

Here, we present 3D-architecture high-capacity silicon anode for lithium-ion battery synthesized via a scalable low-cost chemical vapor deposition (CVD) synthesis. Our research efforts have culminated in the outstanding performance of 3D silicon anode: high areal capacity of up to 5mAh/cm², high gravimetric capacity of up to 3000mAh/gr-Si and a very low irreversible capacity (7-15%). Cycle life over 300 full charge-discharge cycles demonstrated in Si/Li half-cells. Structural batteries are multifunctional materials that expected to perform multiple roles, delivering high energy density and high power capabilities and mechanical support. These binder free anodes are flexible and durable enough to be incorporated in commercial batteries. However, understanding and quantifying the mechanical properties of these multi-phase anodes is imperative for their incorporation in the battery industry.

The adhesion strength of the anode to the current collector, and ductility of the electrodes have been tested, and found to affect the battery handling during manufacturing and its cycle ability.

Properly realized, the 3D-architecture silicon anodes have the potential to increase the energy density of lithium ion batteries by 60%, which is extremely important for electric vehicles, storage devices and portable applications. In addition, these batteries are safer than Li-ion and lithium-metal cells due to high melting points of lithium-rich silicon compounds, and higher working potentials (vs. Li).