Sycamore fruit seed-based hard carbon anode material with high cycle stability for sodium-ion battery

摘要

Hard carbon is considered to be one of the most promising anodes for sodium-ion batteries (SIBs), but high cost and poor cycle stability limit the large-scale application for SIBs. Here, a new kind of low-cost sycamore fruit seed hard carbon was prepared by facile pyrolysis at different temperatures as anode for SIBs. With the large interlayer spacing, the reversible specific capacity of sycamore fruit seed carbonized at 1100 °C can reach 323 mAh g~(-1) at the current density of 0.1 C. When cycled at 0.4 C, the reversible specific capacity is 246.9 mAh g~(-1), following the capacity retention is 87.85% after 300 cycles. Moreover, we find although the different interlayer spacings (d_(002) ≥ 0.37 nm) of graphite crystallites of the obtained hard carbon beneficial for the Na~+ storage, the smaller d_(002) limits the diffusion of Na~+ inevitably, which affects their cycle stability. This research furnishes a competitive choice about anode materials for the industrialized SIBs.