1 research outputs found
Hierarchical Micron-Sized Mesoporous/Macroporous Graphene with Well-Tuned Surface Oxygen Chemistry for High Capacity and Cycling Stability Li–O<sub>2</sub> Battery
Nonaqueous Li–O<sub>2</sub> battery is recognized as one of the most promising energy storage
devices for electric vehicles due to its super-high energy density.
At present, carbon or catalyst-supporting carbon materials are widely
used for cathode materials of Li–O<sub>2</sub> battery. However,
the unique electrode reaction and complex side reactions lead to numerous
hurdles that have to be overcome. The pore blocking caused by the
solid products and the byproducts generated from the side reactions
severely limit the capacity performance and cycling stability. Thus,
there is a great need to develop carbon materials with optimized pore
structure and tunable surface chemistry to meet the special requirement
of Li–O<sub>2</sub> battery. Here, we propose a strategy of
vacuum-promoted thermal expansion to fabricate one micron-sized graphene
matrix with a hierarchical meso-/macroporous structure, combining
with a following deoxygenation treatment to adjust the surface chemistry
by reducing the amount of oxygen and selectively removing partial
unstable groups. The as-made graphene demonstrates dramatically tailored
pore characteristics and a well-tuned surface chemical environment.
When applied in Li–O<sub>2</sub> battery as cathode, it exhibits
an outstanding capacity up to 19 800 mA h g<sup>–1</sup> and
is capable of enduring over 50 cycles with a curtaining capacity of
1000 mA h g<sup>–1</sup> at a current density of 1000 mA g<sup>–1</sup>. This will provide a novel pathway for the design
of cathodes for Li–O<sub>2</sub> battery