The Electrochemical Properties of Hyperbranched Polymer Nanocoated Cathode Materials

We introduce a novel type of surface nanostructured cathode materials. This approach relies on hyperbranched polymer beforehand directed nanoscale coating. The polymer coating successfully forms a uniform coverage onto the surface of the active materials. TEM photograph shows that lithium metal oxide particle is well decorated by polymer coating with 10 nm thickness.  

Cycling performance (Figure 1) of modified electrode is comparing with pristine electrode at 1C charge rate with cut-off voltage 4.4V. Even after 300 cycles, the cells with modified electrode maintain at higher capacity level. On the other hand, the cells with pristine electrode quickly fade out.

These results demonstrate that the polymer coating effectively prevents the direct contact between electrodes and electrolytes that are highly vulnerable to electrochemical decomposition at high voltage conditions. Polymeric coating can also behave as interfacial protection layer that suppress the undesired interfacial reactions.