Regensburg 2022 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 15: Materials for Energy Storage (joint session KFM/CPP)

KFM 15.3: Vortrag

Mittwoch, 7. September 2022, 10:10–10:30, H7

Elucidation of the Pore Formation Mechanism in Hard-Carbon Microspheres — •Martin Wortmann¹, Waldemar Keil², Michael Westphal¹, Elise Diestelhorst³, Jan Biedinger¹, Bennet Brockhagen³, Günter Reiss¹, Claudia Schmidt², Klaus Sattler⁴, and Natalie Frese¹ — ¹Bielefeld University, Bielefeld, Germany — ²Paderborn University, Paderborn, Germany — ³Bielefeld University of Applied Sciences, Bielefeld, Germany — ⁴University of Hawaii, Honolulu, USA

Micro-spherical hydrochar can be carbonized by pyrolysis to produce hard-carbon microspheres with excellent electrochemical properties for the application as anode material in batteries. In this contribution, a temperature-resolved study of the chemical and morphological evolution of saccharide-derived hydrochar during pyrolysis up to 1000°C is presented. By combining a wide range of characterization methods all aspects of the structural transition are examined. The chemical processes occurring both in the bulk and at the surface of the carbon spheres are shown to affect the transition from an amorphous-polymeric to a nanocrystalline carbon-structure. The study focuses on the pore formation mechanism, which is driven by the aggregation of nanometer-sized oxygen-rich clusters at the sphere surface, which disintegrate in a narrow temperature range, leaving behind a mesoporous structure. The revealed molecular mechanisms provide key insights into the pyrolysis of carbonaceous materials.