Egg-Box Structure in Cobalt Alginate: A New Approach to Multifunctional Hierarchical Mesoporous N-Doped Carbon Nanofibers for Efficient Catalysis and Energy Storage

Abstract

Carbon nanomaterials with both doped heteroatom and porous structure represent a new class of carbon nanostructures for boosting electrochemical application, particularly sustainable electrochemical energy conversion and storage applications. We herein demonstrate a unique large-scale sustainable biomass conversion strategy for the synthesis of earth-abundant multifunctional carbon nanomaterials with well-defined doped heteroatom level and multimodal pores through pyrolyzing electrospinning renewable natural alginate. The key part for our chemical synthesis is that we found that the egg-box structure in cobalt alginate nanofiber can offer new opportunity to create large mesopores (∼10–40 nm) on the surface of nitrogen-doped carbon nanofibers. The as-prepared hierarchical carbon nanofibers with three-dimensional pathway for electron and ion transport are conceptually new as high-performance multifunctional electrochemical materials for boosting the performance of oxygen reduction reaction (ORR), lithium ion batteries (LIBs), and supercapacitors (SCs). In particular, they show amazingly the same ORR activity as commercial Pt/C catalyst and much better long-term stability and methanol tolerance for ORR than Pt/C via a four-electron pathway in alkaline electrolyte. They also exhibit a large reversible capacity of 625 mAh g–1 at 1 A g–1, good rate capability, and excellent cycling performance for LIBs, making them among the best in all the reported carbon nanomaterials. They also represent highly efficient carbon nanomaterials for SCs with excellent capacitive behavior of 197 F g–1 at 1 A g–1 and superior stability. The present work highlights the importance of biomass-derived multifunctional mesoporous carbon nanomaterials in enhancing electrochemical catalysis and energy storage.

Porous One‐Dimensional Nanomaterials: Design, Fabrication and Applications in Electrochemical Energy Storage

“…[45][46][47][48][49] Electrochemical energy storage technology, in particular, benefits from porous materials because pores enable higher surface area and faster electrolyte access to active walls. [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68] The intent of this review is to summarize recent advances related to this topic and, more importantly, to provide systematic understanding of porous 1D nanomaterials and their advantages for electrochemical energy storage. As shown in Figure 1, we define different types of (3 of 39) 1602300 porous 1D nanostructures to include general porous 1D nanostructure, hollow 1D geometry (also named a tubular nanostructure), hierarchical porous 1D architecture, nanoparticles in porous 1D configuration, and porous 1D nanoarray.…”

Biomass-derived carbon materials with structural diversities and their applications in energy storage

“…For example, Li et al [68] reported N-doped porous carbon nanofibers by the pyrolysis of electrospun alginate nanofibers derived from seaweed. The egg-box shaped cobalt alginate nanofiber can create mesopores (10-40 nm) at the surface of N-doped carbon nanofibers by removing the cobalt nanoparticles.…”

Macroscopic‐Scale Three‐Dimensional Carbon Nanofiber Architectures for Electrochemical Energy Storage Devices

“…[226][227][228][229][230] It is believed that the 3D CNF nanostructures not only facilitate the rapid transport of electrons along the interconnected carbon network, but also provide multidimensional buffer space for relieving the volume changes during the lithiation/ delithiation process, thereby further enhancing Li + storage capacities and improving the life span. There are various materials, including carbon materials, [40,231] metal oxides, [103,109] Si, [232] metal sulfides, [105,233] and metal phosphides, being used for constructing 3D CNF architectures as the anodes of LIBs. Specifically, CNF gels prepared by Fan and their coworkers are employed for the anodes of LIBs, showing a high reversible lithium capacity of 667 mA h g -1 at 0.12 mA cm -2 , good highrate performance, and long cycling stability, which is superior to those of pure graphene, natural graphite, and CNTs.…”

“…The carbon nanomaterials with well-defined doped heteroatom level and multimodal pores by pyrolyzing electrospinning renewable natural alginate are applied for the electrodes of LIBs. [231] They exhibit a large reversible capacity of 625 mA h g -1 at 1.0 A g -1 , good rate capability, and excellent cycling performance. The CNF gel derived from the BC is also a promising precursor for the anodes of LIBs.…”