부산대학교 도서관

The dimensional stability of SnO2 nanoparticles during Li+ insertion/de-insertion was improved by confining them within a highly crosslinked graphene framework. The composite was synthesized by reacting an optimal amount of bezene-1,4-diboronic acid (BDBA) with SnO2-anchored graphene oxide (SG) that had a high density of oxygen functionalities. The latter was prepared by irradiating ozone on as-synthesized SG. The resultant composite (SGF) possessed a high boron/carbon ratio and a low fraction of unreacted boronic acid moieties, indicating the production of a highly crosslinked framework. The SGF showed excellent stability with a high capacity when cycled between 0.1 and 3.0 V vs. Li/Li+. A decrease of the low-end potential limit induced instability of the boronic ester linkage, which led to a relatively fast capacity fading. The SGF delivered capacities greater than 940 mAh*g[?]1 after 150 cycles at 200 mA*g[?]1, with a fading rate of 1.3 mAh*g[?]1*cycle[?]1 (from 2nd to 150th cycles). This was contrasted with 10.4 mAh*g[?]1*cycle[?]1 for SGF prepared without ozone-treatment and cycled between 0.01 and 3.0 V vs. Li/Li+. The rate capabilities of SGF were also comparable to or better than those reported previously for SnO2/graphene composites, implying that the highly crosslinked framework does not hamper the electroactivity of SnO2 nanoparticles.