Large-volume-expansion-induced material pulverization severely limits the electrochemical performance of high-capacity red phosphorus (RP) in alkali-ion batteries. Honeycomb-like porous materials can effectively solve the issues due to their abundant interconnected pore structures. Nevertheless, it is difficult and greatly challenging to fabricate a honeycomb-like porous RP that has not yet been fabricated via chemical synthesis. Herein, we successfully fabricate a honeycomb-like porous micron-sized red phosphorus (HPRP) with a controlled pore structure via a large-scale green and template-less hydrothermal strategy. It is demonstrated that dissolved oxygen in the solution can accelerate the destruction of P9 cages of RP, thus forming abundant active defects with a faster reaction rate, so the fast corrosion forms the honeycomb-like porous structure. Owing to the free volume, interconnected porous structure, and strong robustness, the optimized HPRP-36 can mitigate drastic volume variation and prevent pulverization during cycling resulting in tiny particle-level outward expansion, demonstrated by in situ TEM and ex situ SEM analysis. Thus, the HPRP-36 anode delivers a large reversible capacity (2587.4 mAh g-1 at 0.05 A g-1) and long-cycling stability with over 500 cycles (∼81.9% capacity retention at 0.5 A g-1) in lithium-ion batteries. This generally scalable, green strategy and deep insights provide a good entry point in designing honeycomb-like porous micron-sized materials for high-performance electrochemical energy storage and conversion.
Keywords: electrochemical energy storage; green and template-less synthesis; honeycomb-like porous structure; lithium ion batteries; red phosphorus.