Project Details
Projekt
MEPP based modelling and simulation of phase transformation and phase formation in the LAS system by considering mixed kinetic phenomena during solidification
Applicant
Professor Dr. Michael Fischlschweiger
Subject Area
Technical Thermodynamics
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 470323858
Tailored Lithium-Ion Battery (LIB) slag solidification is of particular interest in the context of Engineered Artificial Minerals (EnAM). The Li-Al-Si-O (LAS) system is recognised as a prominent slag subsystem, making it a critical material system in slag processing for lithium-ion battery recycling. In order to develop tailored Li-Al-Si-O (LAS) slag designs by adjusting initial slag compositions in the liquid state and tuning time-dependent heat extractions to achieve high Li-containing crystalline phases during solidification, a fundamental understanding of the influence of mixed kinetic phenomena, i.e., solid/liquid interface migration, mass and heat diffusion, on time-dependent phase transformation and morphological formation is required. Understanding the interplay between mixed internal kinetics, external heat extraction and particular composition allows the design of slag compositions and processing strategies that facilitate tailored crystallizations and enable the entrapment of critical elements such as Li in high concentration within the artificially engineered phases. Today, no thermodynamic model exists that is capable of capturing the mixed kinetic phenomena occurring in this system in a holistic manner, such that time-dependent multidimensional phase formation can be predicted qualitatively and quantitatively, based on particular heat extractions. The goal is to develop a multidimensional non-equilibrium thermodynamic model based on the Maximum Entropy Production Principle (MEPP), where heterogeneous temperature fields are considered to simulate the time-dependent phase transformation and phase morphology development in the LAS system during solidification. The kinetic evolution equations as well as the phase selection criterion for the multidimensional growth processes of the respective phases are systematically developed within the MEPP framework. The kinetic coefficients of the developed multidimensional non-equilibrium thermodynamic model are determined by inverse parameter determination based on solidification experiments. Using the experimentally validated model, calculations are performed to develop an optimal initial slag composition in the liquid state and a tailored time-dependent solidification path for LAS to achieve specific morphologies of high Li-containing crystalline phases. To demonstrate that the new approach is effectively transferable to other slag systems relevant to the SPP, it will be applied to the crystallization of LiMnO2 polymorphs from Li-Si-Mn-O melts in collaboration with SPP partners, serving as a final hypothesis test of this approach.
DFG Programme
Priority Programmes
