Micrometer-Sized Porous Fe₂ N/C Bulk for High-Areal-Capacity and Stable Lithium Storage

High-capacity anodes of lithium-ion batteries generally suffer from poor electrical conductivity, large volume variation, and low tap density caused by prepared nanostructures, which make it an obstacle to achieve both high-areal capacity and stable cycling performance for practical applications. Herein, micrometer-sized porous Fe₂ N/C bulk is prepared to tackle the aforementioned issues, and thus realize both high-areal capacity and stable cycling performance at high mass loading. The porous structure in Fe₂ N/C bulk is beneficial to alleviate the volumetric change. In addition, the N-doped carbon conducting networks with high electrical conductivity provide a fast charge transfer pathway. Meanwhile, the micrometer-sized Fe₂ N/C bulk exhibits a higher tap density than that of commercial graphite powder (1.03 g cm^-3 ), which facilitates the preparation of thinner electrode at high mass loadings. As a result, a high-areal capacity of above 4.2 mA h cm^-2 at 0.45 mA cm^-2 is obtained at a high mass loading of 7.0 mg cm^-2 for LIBs, which still maintains at 2.59 mA h cm^-2 after 200 cycles with a capacity retention of 98.8% at 0.89 mA cm^-2 .