A battery electrode material includes: 1) primary particles formed of an electrochemically active material; and 2) a secondary particle defining multiple, discrete internal volumes, wherein the primary particles are disposed within respective ones of the internal volumes.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
 This invention was made with Government support under contract no. DE-AC02-05CH11231 awarded by the Department of Energy. The Government has certain rights in the invention.