Advanced Li- and Na-Batteries
At the heart of the activities under this focus subject lies the design principle for "anode-free" or "zero excess" Li-metal (or Na-metal) batteries, where the alkali-metal plates onto the current collector during charging. Our research targets anode-free systems through three strategies: electrolyte modification with additives for stability and dendrite suppression, functional layers for robust interfaces and homogenous deposition, and 3D interlayers to enable uniform lithium (or sodium) plating and stripping. These approaches tackle key challenges in safety, efficiency, and scalability, paving the way for high-energy-density anode-free batteries designed for next-generation energy storage solutions.
“Anode-free” or “Zero-excess” lithium-metal batteries offer a pathway to significantly higher energy density by eliminating the traditional carbon-based anode and instead plating lithium/sodium directly onto the current collector during charge - and stripping it from the current collector during discharge. However, this design faces critical challenges, including non-uniform lithium/sodium deposition/dissolution and low coulombic efficiency through severe capacity losses caused by the formation of dead lithium/sodium and unstable solid-electrolyte interfaces. The limited lithium/sodium inventory in full cells exacerbates these issues, leading to rapid degradation of cycling performance. To overcome these barriers, we follow three strategies: Electrolyte modification, current collector modification and interfacial modification with 3D interlayers.
Electrolyte Modification
Developing effective electrolytes is critical for advancing anode-free lithium-metal batteries through the stabilization of the electrolyte / Li-metal interface. The instability of this interface leads to non-homogenous Li deposition and Li consumption. We address the challenges by developing a dual-additive strategy, incorporating LiAsF6 and fluoroethylene carbonate that enhances the solid-electrolyte interphase, thus achieving a capacity retention of 75% after 50 cycles in full cells 1. Electrolyte engineering not only stabilizes and enables the anode-free approach but also supports stable cycling at high voltages, making high-energy-density configurations practical. Our dual-salt electrolytes optimized for solvation structures facilitate homogeneous lithium-ion transport, achieving cycling efficiencies exceeding 85% over 400 cycles at high voltages of up to 4.7 V 2 . This integrated approach highlights the dual benefit of organic electrolyte modifications: stabilizing anode-free designs while enabling practical, scalable, high-energy-density solutions for sustainable energy storage.
Further information at ProMoBis.
3D Interlayers
The implementation of 3D interlayers has emerged as a transformative approach to enable homogeneous lithium plating and stripping, paving the way for anode-free lithium-metal batteries. Our interlayers, composed of lithiophilic and lithiophobic materials within porous carbon matrices, feature a core-to-shell lithiophilic-lithiophobic gradient within the carbon fibers 1,2. This innovative structure ensures uniform lithium-ion deposition, prevents concentrated lithium growth, and mitigates stress during volumetric changes. Additionally, chemically prelithiated composite interlayers, incorporating silver and copper, enhance ionic and electronic conductivity, minimize lithium-ion loss, and stabilize the solid-electrolyte interface. As a result, our strategy delivers exceptional cycling stability, with zero-excess lithium-metal batteries achieving over 300 cycles at 1.17 C with negligible capacity fading. This advancement marks a significant step toward practical anode-free designs, combining high energy density with long-term reliability.
Further information at HIPSTER.
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Last Modified: 09.02.2025