Graphene-Co/CoO shaddock peel-derived carbon foam hybrid as anode materials for lithium-ion batteries

A novel graphene (G)-Co/CoO shaddock peel-derived carbon foam (SPDCF) hybrid was fabricated as anode materials for lithium-ion batteries. The preparation of G-Co/CoO SPDCF was according to the following two steps. Firstly, the dried shaddock peels were immersed into the mixture of Co(NO3)2/graphene oxide for about 12 h. Then, the shaddock peels were taken out and heated at 800 °C for 2 h under N2 atmosphere. The strategy is simple, low-cost, and environmentally friendly because the shaddock peel is abundant and renewable. The obtained G-Co/CoO SPDCF hybrid were carefully characterized by SEM, EDS, XPS, XRD, TGA, BET, TEM, and electrochemical techniques. The results showed that the carbonized shaddock peels had hierarchical porous nanoflakes structures and graphene was uniformly dispersed into the SPDCF. The nanosized Co/CoO was formed on the G-SPDCF. The resulted G-Co/CoO SPDCF hybrid could maintain a high capacity of 600 mA h g−1 at 0.2 A g−1 after 80 cycles, which was much higher than that of commercial graphite (372 mA h g−1). The enhanced performance might be ascribed to the existence of lots of uniform Co/CoO and the hierarchical G-SPDCF alleviating the mechanical stress during the process of lithiation/delithiation.