Pre‐Oxidation Strategy Transforming Waste Foam to Hard Carbon Anodes for Boosting Sodium Storage Performance

Abstract

Large reserves, high capacity, and low cost are the core competitiveness of disordered carbon materials as excellent anode materials for sodium‐ion batteries (SIBs). And the existence and improper treatment of a large number of organic solid wastes will aggravate the burden on the environment, therefore, it is significant to transform wastes into carbon‐based materials for sustainable energy utilization. Herein, a kind of hard carbon materials are reported with waste biomass‐foam as the precursor, which can improve the sodium storage performance through pre‐oxidation strategy. The introduction of oxygen‐containing groups can promote structural cross‐linking, and inhibit the melting and rearrangement of carbon structure during high‐temperature carbonization that produces a disordered structure with a suitable degree of graphitization. Moreover, the micropore structure are also regulated during the high‐temperature carbonization process, which is conducive to the storage of sodium ions in the low‐voltage plateau region. The optimized sample as an electrode material exhibits excellent reversible specific capacity (308.0 mAh g−1) and initial Coulombic efficiency (ICE, 90.1%). In addition, a full cell with the waste foam‐derived hard carbon anode and a Na3V2(PO4)3 cathode is constructed with high ICE and energy density. This work provides an effective strategy to conversion the waste to high‐value hard carbon anode for sodium‐ion batteries.

One-Step Construction of Closed Pores Enabling High Plateau Capacity Hard Carbon Anodes for Sodium-Ion Batteries: Closed-Pore Formation and Energy Storage Mechanisms

“…Moreover, the reversible specific capacity/plateau capacity of GHC x is significantly lower than that of ZGHC1500. Figure g and Table S4 provide a comparison on the reversible specific capacity/plateau capacity of ZGHC1500 anode with the recently reported hard carbon anodes for SIBs, ,,,,,,− demonstrating its leading position.…”

“…Preoxidation is a method for constructing closed pores. Generally, preoxidation can boost the degree of cross-linking of the precursors, which can hinder the orientated growth of graphitic domains during carbonization, thereby constructing more amorphous carbon microstructures and further forming numerous closed pores. ,, However, the number of closed pores constructed by preoxidation strategies is usually limited, which only results in a slight enhancement of low-voltage plateau capacity for hard carbon. Compared to preoxidation, introducing pore-forming agents including hard templates (e.g., nanosized MgO , and ZnO , ), organics (e.g., ethanol and polyethylene glycol), and activation agents (e.g., KOH) is a more direct way to construct closed pores, allowing for the production of high plateau capacity hard carbon anodes in general.…”

Regulating the Pore Structure of Activated Carbon by Pitch for High-Performance Sodium-Ion Storage

“…Galvanostatic intermittent titration (GITT) tests were conducted on the composites to investigate the variation in the diffusion behavior of Na + in the discharge curve . According to Figure g, it can be observed that XA-4T-1300 exhibits longer low-voltage plateau regions.…”

“…A number of existing pore structural design strategies, such as preoxidation, pore-forming agents, and filling of carbonaceous precursors, can effectively increase the volume of closed pores in disordered carbon materials and enhance the sodium-ion storage capacity . Meng et al obtained phenolic resin-based carbon negative electrodes with a closed pore structure by using ethanol as a pore-forming agent .…”