Biomass derived erythrocyte-like hard carbon as anodes for high performing full sodium-ion batteries

Abstract

Herein, a novel hard carbon is prepared via one-step pyrolysis process from waste Ganoderma spores. We explore four pyrolysis temperatures and obtain the hard carbon product (NG-700) with the best performance. Ganoderma spores are hard that the prototype structure is reserved after pyrolysis process. The NG-700 is erythrocyte-like shape with hollow structure which can hold electrolyte. Many nitrogen atoms doping in NG-700 improve the conductivity of the material and provide more absorption sites. Moreover, the porous structure of NG-700 is conducive to entering of electrolyte and relieving volume expansion during cycling. In sodium-ion half-cells, the NG-700 electrode maintains 165 mA h g−1 for 10,000 cycles at 2 A g−1. In sodium-ion full-cells, the NG-700 anode can keep the capacity of 94 mA h g−1 for 200 cycles at 0.1 A g−1 paired with Na3V2(PO4)3 cathodes. Under severe environmental conditions (−25 °C), the electrode's capacity retention rate is 50 %.