Carbon‐Nanotube‐Cored Cobalt Porphyrin as a 1D Nanohybrid Strategy for High‐Performance Lithium‐Ion Battery Anodes

Abstract

AbstractRedox‐active organic electrode materials have garnered considerable interest as an emerging alternative to currently widespread inorganic‐(or metal)‐based counterparts in lithium‐ion batteries (LIBs). Practical use of these materials, however, has posed a challenge due to their electrically insulating nature, limited specific capacity, and poor electrochemical durability. Here, a new class of multiwalled‐carbon‐nanotube‐(MWCNT)‐cored, meso‐tetrakis(4‐carboxyphenyl)porphyrinato cobalt (CoTCPP) is demonstrated as a 1D nanohybrid (denoted as CC‐nanohybrid) strategy to develop an advanced LIB anode. CoTCPP, which is one of the metalloporphyrins having multielectron redox activities, shows strong noncovalent interactions with MWCNTs due to its conjugated π‐bonds, resulting in successful formation of the CC‐nanohybrids. The structural uniqueness of the CC‐nanohybrid facilitates electron transport and electrolyte accessibility, thereby improving their redox kinetics. Inspired by the 1D structure of the CC‐nanohybrid, all‐fibrous nanomat anode sheets are fabricated through concurrent electrospraying/electrospinning processes. The resulting nanomat anode sheets, driven by their 3D bicontinuous ion/electron conduction pathways, provide fast lithiation/delithiation kinetics, eventually realizing the well‐distinguishable lithiation behavior of CoTCPP. Notably, the nanomat anode sheets exhibit exceptional electrochemical performance (≈226 mAh gsheet −1 and >1500 cycles at 5 C) and mechanical flexibility that lie far beyond those achievable with conventional LIB anode technologies.