Martin Finsterbusch

Bio: Martin Finsterbusch is an academic researcher from Forschungszentrum Jülich. The author has contributed to research in topics: Materials science & Electrolyte. The author has an hindex of 12, co-authored 44 publications receiving 539 citations.

A garnet structure-based all-solid-state Li battery without interface modification: resolving incompatibility issues on positive electrodes

Abstract: The development of high-performance Li7La3Zr2O12 (LLZO)-based all-solid-state lithium batteries (SSLB) is usually hampered by highly resistive interfaces due to the need for sintering at elevated temperatures to form ionic diffusion paths through the grains. Many strategies have been proposed to solve the problem but the achievements have been limited. Herein, a new design principle is introduced, based on co-sintering crystalline LCO and Ta-substituted LLZO instead of using the more reactive Li–Co–O precursors and Al-substituted LLZO, which allows the fabrication of high specific areal density and low cell area resistance without the interface modification of LLZO-based SSLB. Detailed studies using micro-Raman and EDS mapping revealed that the well-sintered interfaces are free from detrimental secondary phases. To demonstrate that a true bulk-type SSLB can be constructed by this straightforward strategy, the material loading for a composite positive electrode was increased to about 10 times that in previous reports, which resulted in a high areal capacity of 1.63 mA h cm−2 (i.e. 110 mA h g−1) when discharged with a current density of 50 μA cm−2. It also allows one to discharge the fabricated SSLB at a very high current density of 500 μA cm−2 at 50 °C due to the minimized cell areal resistance. The new fabrication strategy for the LLZO-based SSLB paves the way for achieving SSLB with high safety and energy density.

Li7La3Zr2O12 Interface Modification for Li Dendrite Prevention

Abstract: Al-contaminated Ta-substituted Li7La3Zr2O12 (LLZ:Ta), synthesized via solid-state reaction, and Al-free Ta-substituted Li7La3Zr2O12, fabricated by hot-press sintering (HP-LLZ:Ta), have relative densities of 92.7% and 99.0%, respectively. Impedance spectra show the total conductivity of LLZ:Ta to be 0.71 mS cm(-1) at 30 °C and that of HP-LLZ:Ta to be 1.18 mS cm(-1). The lower total conductivity for LLZ:Ta than HP-LLZ:Ta was attributed to the higher grain boundary resistance and lower relative density of LLZ:Ta, as confirmed by their microstructures. Constant direct current measurements of HP-LLZ:Ta with a current density of 0.5 mA cm(-2) suggest that the short circuit formation was neither due to the low relative density of the samples nor the reduction of Li-Al glassy phase at grain boundaries. TEM, EELS, and MAS NMR were used to prove that the short circuit was from Li dendrite formation inside HP-LLZ:Ta, which took place along the grain boundaries. The Li dendrite formation was found to be mostly due to the inhomogeneous contact between LLZ solid electrolyte and Li electrodes. By flatting the surface of the LLZ:Ta pellets and using thin layers of Au buffer to improve the contact between LLZ:Ta and Li electrodes, the interface resistance could be dramatically reduced, which results in short-circuit-free cells when running a current density of 0.5 mA cm(-2) through the pellets. Temperature-dependent stepped current density galvanostatic cyclings were also carried out to determine the critical current densities for the short circuit formation. The short circuit that still occurred at higher current density is due to the inhomogeneous dissolution and deposition of metallic Li at the interfaces of Li electrodes and LLZ solid electrolyte when cycling the cell at large current densities.

High Capacity Garnet-Based All-Solid-State Lithium Batteries: Fabrication and 3D-Microstructure Resolved Modeling

Abstract: The development of high-capacity, high-performance all-solid-state batteries requires the specific design and optimization of its components, especially on the positive electrode side. For the first time, we were able to produce a completely inorganic mixed positive electrode consisting only of LiCoO2 and Ta-substituted Li7La3Zr2O12 (LLZ:Ta) without the use of additional sintering aids or conducting additives, which has a high theoretical capacity density of 1 mAh/cm2. A true all-solid-state cell composed of a Li metal negative electrode, a LLZ:Ta garnet electrolyte, and a 25 μm thick LLZ:Ta + LiCoO2 mixed positive electrode was manufactured and characterized. The cell shows 81% utilization of theoretical capacity upon discharging at elevated temperatures and rather high discharge rates of 0.1 mA (0.1 C). However, even though the room temperature performance is also among the highest reported so far for similar cells, it still falls far short of the theoretical values. Therefore, a 3D reconstruction of th...

A solid future for battery development

Abstract: Solid-state batteries have recently attracted great interest as potentially safe and stable high-energy storage systems. However, key issues remain unsolved, hindering full-scale commercialization.

Fundamentals of inorganic solid-state electrolytes for batteries

Abstract: In the critical area of sustainable energy storage, solid-state batteries have attracted considerable attention due to their potential safety, energy-density and cycle-life benefits. This Review describes recent progress in the fundamental understanding of inorganic solid electrolytes, which lie at the heart of the solid-state battery concept, by addressing key issues in the areas of multiscale ion transport, electrochemical and mechanical properties, and current processing routes. The main electrolyte-related challenges for practical solid-state devices include utilization of metal anodes, stabilization of interfaces and the maintenance of physical contact, the solutions to which hinge on gaining greater knowledge of the underlying properties of solid electrolyte materials. Solid-state batteries are attractive due to their potential safety, energy-density and cycle-life benefits. Recent progress in understanding inorganic solid electrolytes considering multiscale ion transport, electrochemical and mechanical properties, and processing are discussed.

Promises, Challenges, and Recent Progress of Inorganic Solid-State Electrolytes for All-Solid-State Lithium Batteries

Abstract: All-solid-state lithium batteries (ASSLBs) have the potential to revolutionize battery systems for electric vehicles due to their benefits in safety, energy density, packaging, and operable temperature range. As the key component in ASSLBs, inorganic lithium-ion-based solid-state electrolytes (SSEs) have attracted great interest, and advances in SSEs are vital to deliver the promise of ASSLBs. Herein, a survey of emerging SSEs is presented, and ion-transport mechanisms are briefly discussed. Techniques for increasing the ionic conductivity of SSEs, including substitution and mechanical strain treatment, are highlighted. Recent advances in various classes of SSEs enabled by different preparation methods are described. Then, the issues of chemical stabilities, electrochemical compatibility, and the interfaces between electrodes and SSEs are focused on. A variety of research addressing these issues is outlined accordingly. Given their importance for next-generation battery systems and transportation style, a perspective on the current challenges and opportunities is provided, and suggestions for future research directions for SSEs and ASSLBs are suggested.