ZnO Hard Templating for Synthesis of Hierarchical Porous Carbons with Tailored Porosity and High Performance in Lithium‐Sulfur Battery

Abstract

Hierarchical porous carbon (HPC, DUT‐106) with tailored pore structure is synthesized using a versatile approach based on ZnO nanoparticles avoiding limitations present in conventional silica hard templating approaches. The benefit of the process presented here is the removal of all pore building components by pyrolysis of the ZnO/carbon composite without any need for either toxic/reactive gases or purification of the as‐prepared hierarchical porous carbon. The carbothermal reduction process is accompanied by an advantageous growing of distinctive micropores within the thin carbon walls. The resulting materials show not only high internal porosity (total pore volume up to 3.9 cm3 g−1) but also a large number of electrochemical reaction sites due to their remarkably high specific surface area (up to 3060 m2 g−1), which renders them particularly suitable for the application as sulfur host material. Applied in the lithium‐sulfur battery, the HPC/sulfur composite exhibits a capacity of >1200 mAh g−1‐sulfur (>750 mAh g−1 electrode) at a high sulfur loading of ≥ 3 mg cm−2 as well as outstanding rate capability. In fact, this impressive performance is achieved even using a low amount of electrolyte (6.8 μl mg−1 sulfur) allowing for further weight reduction and maintenance of high energy density on cell level.

Synthesis of hierarchically porous MnO2/rice husks derived carbon composite as high-performance electrode material for supercapacitors

“…Interconnected macropores, mesopores and micropores existed in the microstructure of HPCs would facilitate ions transport and enhance power capability [33]. HPCs are usually prepared from polymer precursors using template-assisted or self-templating methods [34,35]. In recent years, a lot of biomass including nutshells, plant fibres and animal bones with natural hierarchical structures have been transformed into HPCs through selfstructuring or artificial regulation [36][37][38].…”

Glucose derived ionothermal carbons with tailor-made porosity

“…Templating methods can overcome those drawbacks and lead to well defined, highly ordered and even hierarchically structured pore systems combining micro-(d < 2 nm), meso-(2 nm < d < 50 nm) and macropores (d > 50 nm). [9,14,[16][17][18] Nevertheless, these strategies often comprise a two-step procedure with a low temperature reaction and a successive post heat treatment to achieve high SSAs which is the case for soft templating. The often used hard templating requires the utilization of harsh chemicals such as hydrofluoric acid or strong bases leading to restricted scalability.…”

Zinc-salt templating of hierarchical porous carbons for low electrolyte high energy lithium-sulfur batteries (LE-LiS)

“…Nevertheless, a hierarchical porous system cannot be obtained by overcoming the activation process. Recently, our group established a ZnO hard templating approach allowing an efficient in situ template removal without any need of toxic/reactive gases as well as purification steps [36]. Moreover, the carbothermal reduction induced a growth of distinctive microporosity within the carbon walls leading to a hierarchical porous carbon with specific surface areas exceeding 3000 m² g -1 as well as meso/macropores in range of 20 -200 nm with high performance in lithium-sulfur batteries.…”