Electrode Including Nanostructures for Rechargeable Cells

Abstract

A lithium ion battery electrode includes silicon nanowires used for insertion of lithium ions and including a conductivity enhancement, the nanowires growth-rooted to the conductive substrate.

Description

FIELD OF THE INVENTION[0001]The present invention relates generally to electrochemical cell components and methods of preparing such components and, more specifically, to battery electrodes containing nanowires configured to interact with electrochemically active ions and methods of preparing such electrodes and batteries including such electrodes.BACKGROUND OF THE INVENTION[0002]The demand for high capacity rechargeable batteries is extensive. Many applications, such as aerospace, medical devices, portable electronics, automotive and many others, demand high gravimetric and or volumetric capacity batteries. Development of the lithium ion technology has provided some advances in this area, but higher capacities are still very desirable. Lithium ion cells generally use anodes containing graphite powder that has theoretical capacity of only about 372 mAh / g.[0003]Silicon is an attractive insertion material for lithium and other electrochemically active ions. A theoretical capacity of s...

AI Technical Summary

Benefits of technology

[0005]In certain embodiments, a lithium ion battery electrode includes a conductive substrate and silicon containing nanowires growth-rooted to the conductive substrate. The nanowires include a conductivity enhancement component for reducing electrical resistance of the nanowires. The nanowires are configured for inserting and removing lithium ions during battery cycling. The capacity of at least about 1500 mAh / g is maintained after 20 cycles. In this or other embodiments, the capacity of silicon containing nanowires is at least about 600 mAh / g after 100 cycles.

[0011]Electrodes containing nanowires may be used in a lithium ion battery. In certain embodiments, the battery includes a negative electrode with a conductive substrate and silicon containing nanowires growth-rooted to the conductive substrate, a positive electrode, and a lithium ion transporting medium positioned between the negative electrode and the positive electrode. The negative electrode may be configured for inserting and removing lithium ions during battery cycling while maintaining capacity of at least about 1500 mAh / g after 20 cycles. The nanowires may include a conductivity enhancement component for reducing electrical resistance of the nanowires.

Problems solved by technology

Yet use of silicon and many other high capacity materials for battery applications has been constrained by substantial changes in volume (swelling) of these materials during insertion of active ions.

Volume changes of this magnitude cause substantial stresses in silicon structures in the negative electrodes resulting in pulverization of the structures, loss of electrical connections within the electrode, and capacity fading of the battery.

Further, many high capacity materials, such as silicon, have poor electrical conductivity, and often require special design features or conductive additives that may negatively impact battery capacity.

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