Structure and electrochemistry of copper fluoride nanocomposites utilizing mixed conducting matrices

Near-theoretical utilization of high-energy-density CuF2 positive electrode materials for lithium batteries was enabled through the use of nanocomposites consisting of 2-30 nm domains of CuF2 within a mixed ionic + electronic conducting matrix of a metal oxide. Small but significant crystallographic changes to the core crystal of the CuF2 were found to occur in all oxide-based matrices. These modifications to the core crystal and the surrounding matrix were investigated through a host of characterization methods, including XRD, XPS, and XAS. This new approach to the enablement of the anhydrous CuF2 is distinctly superior in performance to that of macro CuF2 or CuF2 nanocomposites utilizing carbon as a matrix, the latter of which is also introduced herein for the first time.