posted on 2017-01-30, 00:00authored byNicholas
P. Stadie, Shutao Wang, Kostiantyn V. Kravchyk, Maksym V. Kovalenko
High
surface area porous carbon frameworks exhibit potential advantages
over crystalline graphite as an electrochemical energy storage material
owing to the possibility of faster ion transport and up to double
the ion capacity, assuming a surface-based mechanism of storage. When
detrimental surface-related effects such as irreversible capacity
loss due to interphase formation (known as solid-electrolyte interphase,
SEI) can be mitigated or altogether avoided, the greatest advantage
can be achieved by maximizing the gravimetric and volumetric surface
area and by tailoring the porosity to accommodate the relevant ion
species. We investigate this concept by employing zeolite-templated
carbon (ZTC) as the cathode in an aluminum battery based on a chloroaluminate
ionic liquid electrolyte. Its ultrahigh surface area and dense, conductive
network of homogeneous channels (12 Å in width) render ZTC suitable
for the fast, dense storage of AlCl4– ions (6 Å in ionic diameter). With aluminum as the anode, full
cells were prepared which simultaneously exhibited
both high specific energy (up to 64 Wh kg–1, 30
Wh L–1) and specific power (up to 290 W kg–1, 93 W L–1), highly stable cycling performance,
and complete reversibility within the potential range of 0.01–2.20
V.