Pyrite FeS2 has long been used as commercial primary lithium batteries at room temperature. To achieve rechargeable FeS2 battery, biomass-carbon@FeS2 composites are prepared using green and renewable auricularia auricula as carbon source through the process of carbonization and sulfuration. The auricularia auricula has strong swelling characteristics to absorb aqueous solution which can effectively absorb Fe ions into its body. FeS2 homogeneously distributed in biomass carbon matrix performs high electronic and ionic conductivity. The specific capacity of biomass-carbon@FeS2 composites remains 850 mAh g−1 after 80 cycles at 0.5C and 700 mAh g−1 at the rate of 2C after 150 cycles. Biomass-carbon@FeS2 composites exhibit high-rate capacity in lithium-ion battery.