Chain-Networked Micro-Silicon Electrodes Inducing Internal Isostatic Compressive Stress for High-Energy and High-Power Solid-State Batteries

초록

Micron-sized silicon (& micro;-Si) offers a scalable pathway to high-capacity anodes, and its application in solid-electrolyte-free systems has garnered attention as a strategy to maximize energy density. However, achieving both high energy and power densities in such configurations remains challenging due to the lack of internal ionic conduction pathways and stress-accommodation mechanisms. Here, we report a Chain-based Networking (CN)-Si electrode architecture that overcomes these limitations and maximizes energy and power densities without incorporating solid electrolytes within the electrode. In this design, & micro;-Si particles are tightly wrapped and interconnected by single-walled carbon nanotubes (CNTs), forming a mechanically robust conductive network. The CNT wrapping imposes compressive stress during lithiation, distributing internal strain and preventing crack and void formation, mimicking the stress-dissipation principle of Prince Rupert's drop. As a result, the CN-Si electrode delivers superior electrochemical performance, with 78% capacity retention at 3C, significantly outperforming conventional Si electrodes using polymer or carbon black binders. In full-cell configurations with LiNi0.8Mn0.1Co0.1O2 (NCM811) cathodes, the CN-Si electrode retains 78.8% capacity after 3000 cycles at a high C-rate (5C). These findings demonstrate that stress-engineered micro-Si architectures can simultaneously overcome kinetic limitations and maximize both energy and power densities in solid-state battery systems, advancing practical high-performance All-Solid-State Batteries (ASSBs).

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