Surface modified and size-controlled octahedral Cu 2 O nanostructured electrodes for lithium-ion batteries

Abstract

Cu 2 O exhibits a conversion reaction during the electrochemical process for lithium-ion batteries (LIBs). The structural transformation of the electrode during cycling can result in significantly deteriorated electrochemical performance. Therefore, in order to overcome the deterioration in LIB performance when using Cu 2 O as an anode, structure-controlled nanostructures can be prepared using polymers as additives during the synthesis of the electrode. Herein, we prepared size-controlled octahedral Cu 2 O nanostructure electrodes as anodes for LIBs by varying the portion of polyvinylpyrrolidone (PVP, 12, 16, and 20 g)in the synthesis (denoted as Cu 2 O-12, Cu 2 O-16, and Cu 2 O-20, respectively). The as-prepared samples showed an octahedral shape with decreased particle sizes as well as increasing amounts of PVP. In particular, Cu 2 O-16 prepared with a proper amount of PVP showed enhanced LIB performance, which was due to the highest Li + diffusion coefficient and lowest resistance. Furthermore, in order to confirm the effect of PVP in Cu 2 O on electrochemical performance, PVP-removed Cu 2 O-16 and PVP-removed/heated Cu 2 O-16 were prepared. However, the samples prepared after the removal of PVP showed deteriorated cycling and rate performance as compared to Cu 2 O heated in the presence of PVP. As a result, the octahedral Cu 2 O electrode with a proper particle size prepared with PVP as a surfactant and reductant exhibited superior LIB performance. © 2019 Elsevier B.V.