A reconstructed graphite-like carbon micro/nano-structure with higher capacity and comparative voltage plateau of graphite

Abstract

A reconstructed graphite-like carbon (r-GC) micro/nano-structure with a higher capacity than and a comparative voltage plateau to commercial graphite anodes of lithium-ion batteries (LIBs) is synthesized from an expandable graphite raw material based on an up-down-up synthetic strategy. The expandable graphite powders are thermally expanded, hydrothermally cut, and ultrasonically crushed in turn to prepare a suspension containing nano-fragments with a graphitic plane nano-structure as a carbon precursor. Then, the r-GC micro/nano-structure can be obtained by stacking the graphite nano-fragments through spray drying the suspension and subsequently conducting a calcining treatment. This r-GC exhibits an initial capacity of 575.3 mA h g⁻¹ at 0.1C and a reversible capacity of 508.4 mA h g⁻¹ after 100 cycles. Especially, its comparative voltage plateau of commercial graphite is incapable for other known anode materials for LIBs. In the potential window of 0.3–0.01 V (vs. Li⁺/Li), a maximum capacity of approximately 432.1 mA h g⁻¹, 1.16 times the theoretical capacity of graphite (372 mA h g⁻¹), is obtained. The unique element stability, capacity, and voltage plateau indicate that the as-synthesized r-GC is a promising sheet-like anode material for LIBs. In addition, an embedded-defect and graphite-dominant graphite/graphene cooperative lithiation mechanism is proposed to elaborate the capacity and voltage plateau of r-GC.