Abstract:

Water soluble binder has caused extensive concern because of its environmentally friendly, low cost and safety, etc. Cathode slurry can not be configured bacause the agar binder is almost insoluble in water at room temperature. The hydroxyl groups of agar (AG) were partially oxidized to carboxyl groups by H2O2. Oxidized agar (M-AG) can be easily dissolved in water at room temperature. The presence of carboxyl groups may adsorb lithium polysulfide, which inhibits the "shuttle" of lithium polysulfide during the charging and discharging process. In this work, the M-AG was used as binder in lithium-sulfur battery. The good contact among the active material, the conductive agent and the current collector can be well preserved with M-AG as binders. The M-AG does not participate the electrochemical reaction in lithium-sulfur battery. The structure of the electrode can be stabilized during the repeated charging and discharging process. The M-AG electrode has higher capacity release and capacity retention than the conventional PVDF electrode. It delivers an initial specific discharge capacity of 700 mA·h·g1 with a high capacity retention ratio of 90.7% after 100 cycles.