Interconnected hollow nanostructures containing high capacity active materials for use in rechargeable batteries

Abstract

Provided are electrode layers for use in rechargeable batteries, such as lithium ion batteries, and related fabrication techniques. These electrode layers have interconnected hollow nanostructures that contain high capacity electrochemically active materials, (such as silicon, tin, and germanium). In certain embodiments, a fabrication technique involves forming a nanoscale coating around multiple template structures and at least partially removing and / or shrinking these structures to form hollow cavities. These cavities provide space for the active materials of the nanostructures to swell into during battery cycling. This design helps to reduce the risk of pulverization and to maintain electrical contacts among the nanostructures. It also provides a very high surface area available ionic communication with the electrolyte.; The nanostructures have nanoscale shells but may be substantially larger in other dimensions. Nanostructures can be interconnected during forming the nanoscale coating, when the coating formed around two nearby template structures overlap.

Description

[0001] Cross References to Related Applications

[0002] This application claims the benefit of US Provisional Patent Application 61 / 181,637, filed May 27, 2009, entitled "Core-Shell HighCapacity Nanowires for Battery Electrodes," which is hereby incorporated by reference in its entirety for all purposes.

[0003] This application also claims the benefit of US Provisional Patent Application 61 / 183,529, filed June 2, 2009, entitled "Electrospinning to Fabricate Battery Electrodes," which is hereby incorporated by reference in its entirety for all purposes. Background technique

[0004] High capacity electrochemically active materials are desirable for battery applications. However, these materials exhibit significant volume changes during battery cycling, such as swelling during lithiation and contraction during delithiation. For example, silicon expands to its approximately 4200mAh / g during lithiation or Li 4.4 Almost 400% of the theoretical capacity of Si. Volume changes o...

Images