The
applicability of Na-ion batteries is contingent on breakthroughs
in alternative electrode materials that have high capacities and which
are economically viable. Unfortunately, conventional graphite anodes
for Li-ion battery systems do not allow Na-ion accommodation into
their interlayer space owing to the large ionic radius and low stabilizing
energy of Na in graphite. Here, we suggest a promising strategy for
significantly increasing Na capacity by expanding the axial slab space
of graphite. We successfully synthesized reconstructed graphite materials
via self-assembly of negative graphite oxide (GO) flakes and Al cation
(positive) pillars and by subsequent chemical reaction of the obtained
Al-GO materials. Al pillars, atomically distributed in graphite interlayers,
can extend the slab space by up to ∼7 Å, which is a 2-fold
interlayer distance of pristine graphite. An exceptionally high capacity
of 780 mAh/g is demonstrated for reconstructed graphite anodes with
Al pillars, compared with rGO materials (210 mAh/g). We investigated
the electrochemical reaction mechanism and structural changes associated
with discharge and charge to emphasize the benefit of using reconstructed
graphite as anodes in Na-ion batteries. Our strategy of modifying
the interlayer distance by introducing metallic pillars between the
layers can help address the low capacity of carbonaceous anodes.
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