for M 3 Sb, M = K), and high volumetric density (Sb: 6.7 g cm −3 ). [11][12][13][14] However, the huge volume expansion and severe pulverization of alloy-typed metal anodes during the potassiation and depotassiation processes result in a sharp decrease in capacity. The general strategy addresses the issues to downsize the active materials to nano sizes and make composites with elastic carbon materials. These strategies can effectively accommodate the huge volume expansion of alloy-typed metal anodes and shorten the potassium ion diffusion distance in the solid phase, improving their rate performance and cycling stability in batteries. However, due to the simultaneous introduction of nanosized active materials and low-density inactive carbon, the commercial applications are severely impeded by the complex synthesis of alloy-typed metal anodes, insufficient specific capacity (based on the whole electrode), and low tap density generating low volumetric capacity. [12,[15][16][17] Additionally, they display an insufficient initial coulombic efficiency (ICE) due to the use of porous carbon that formed a thick solid electrolyte interphase (SEI). For example, Zhang et al. reported a composite structure (Sb@CNFs) consisting of nano-Sb embedded in carbon nanofibers. [18] This provided a specific capacity of 227 mAh g −1 after 1000 cycles at 1.0 A g −1 . However, its practical application prospects were severely hindered by the low ICE (47 %), stemming from its large specific surface area and the irreversible formation of the thick SEI. To address these issues, micro-sized active materials are preferred as direct anodes due to their large particle sizes, which obviously increase their tap density, and the appropriate specific surface area that effectively reduces the side reactions between the electrolyte and active materials. However, the micro-sized active materials have a prolonged ion diffusion distance in the solid phase and generate severe pulverization because of their large volume expansion. Therefore, their application as anodes in PIBs gave insufficient rate capacity and fast capacity decay, especially in long cycling. Therefore, proposing an effective method for fabricating a unique micro-sized metallic electrode material yet retaining its high tap density is interesting yet challenging, thus to significantly promote the rate capacity and cycling lifespan of micro-sized electrode materials.The tremendous volume change and severe pulverization of micro-sized Sb anode generate no stable capacity in potassium-ion batteries (PIBs). The honeycomb-like porous structure provides free spaces to accommodate its volume expansion and offers efficient ion transport, yet complex synthesis and low yield limits its large-scale application. Here, a green, scalable template-free method for designing a 3D honeycomb-like interconnected porous micro-sized Sb (porous-Sb) is proposed. Its honeycomb-like porous formation mechanism is also verified. Under hydrothermal conditions, Sb reacts with water and dissolved oxygen in water, under...