1 research outputs found
Role of Nitrogen-Doped Graphene for Improved High-Capacity Potassium Ion Battery Anodes
Potassium
is an earth abundant alternative to lithium for rechargeable
batteries, but a critical limitation in potassium ion battery anodes
is the low capacity of KC<sub>8</sub> graphite intercalation compounds
in comparison to conventional LiC<sub>6</sub>. Here we demonstrate
that nitrogen doping of few-layered graphene can increase the storage
capacity of potassium from a theoretical maximum of 278 mAh/g in graphite
to over 350 mAh/g, competitive with anode capacity in commercial lithium
ion batteries and the highest reported anode capacity so far for potassium
ion batteries. Control studies distinguish the importance of nitrogen
dopant sites as opposed to sp<sup>3</sup> carbon defect sites to achieve
the improved performance, which also enables >6× increase
in
rate performance of doped <i>vs</i> undoped materials. Finally, <i>in situ</i> Raman spectroscopy studies elucidate the staging
sequence for doped and undoped materials and demonstrate the mechanism
of the observed capacity enhancement to be correlated with distributed
storage at local nitrogen sites in a staged KC<sub>8</sub> compound.
This study demonstrates a pathway to overcome the limitations of graphitic
carbons for anodes in potassium ion batteries by atomically precise
engineering of nanomaterials