Robust Siloxane Network-Driven Electrostatically Heterogeneous 3D Nano-Assembled Hard Carbon Host toward High...

Achieving high lithium utilization and long-term stability in lithium metal batteries (LMB) with 3D host remains a significant challenge. Herein, a robust siloxane network-driven electrostatically heterogeneous 3D nano-assembled hard carbon (EH-NHC) host is introduced. The 3D EH-NHC host is integrated with a strongly chemical-bonded siloxane coating layer, imparting a negative surface charge originating from the lithiophilic hydroxyl groups (Si─OH). This host retains its thickness of coating layer, surface charge, and structural integrity even after repeated cycling. The lithiophilic sites promote uniform, bottom-up lithium deposition within the porous EH-NHC framework, which accommodates volume changes and enables uniform plating under high areal capacity (5 mAh cm^-2). The EH-NHC host exhibits outstanding stability in symmetric cells, maintaining consistent operation for 4000 h at a current density of 6 mA cm^-2 and 65% Li utilization. Furthermore, LiFePO₄/EH-NHC host full cell demonstrates remarkable cycle stability, achieving capacity retention of 81.5% after 500 cycles, even with a high lithium utilization of 50%. In this study, we demonstrate that EH-NHC is a promising candidate as a practically operable 3D host for next-generation LMBs, preventing degradation of the lithiophilic sites, thus preserving the functionality of the initially designed hierarchical structure and maximizing the reversible efficiency of active lithium.