Regulating closed pore structure enables significantly improved sodium storage for hard carbon pyrolyzing at relatively low temperature

Abstract

The closed pore has been considered as the key structure for Na ion storage in hard carbon. However, the traditional view is that closed pores can only be formed by the curling of graphite-like crystallites in the case of high temperature carbonization. Ingenious designing of closed pore structures at lower temperature is still blank. Herein, for the first time, engineering the wall thickness and number of closed pores in waste rosewood-derived hard carbon was successfully achieved at a low temperature of 1100 • C by removing the lignin and hemicellulose components in wood precursor. When applied as an anode material, the optimum sample exhibits a high capacity of 326 mAh/g at 20 mA/g and a remarkable rate capability of 230 mAh/g at 5000 mA/g, significantly higher than those of the untreated sample (only 33 mAh/g at 5000 mA/g). The significantly improved Na storage performance should be attributed to abundant closed pores that provide sufficient spaces for Na storage and thin pore wall structure that is beneficial to the diffusion of Na + in the bulk phase. This work provides a new idea for the future application of biomass-based hard carbon for advanced Na ion batteries.

Pre-crosslinking enables a promising cyclodextrin-derived carbon anode with large plateau capacity for sodium ion batteries

“…A large body of research suggests that closed pores (inaccessible by gases) in disordered carbons play a crucial role in the storage of sodium. [31][32][33][34] Distinct from N 2 adsorption/desorption measurement, in which it is difficult to detect closed pores in carbons, small-angle X-ray scattering (SAXS) can provide information on full pores including both open and closed pores. 30 Fig.…”

Review: Insights on Hard Carbon Materials for Sodium‐Ion Batteries (SIBs): Synthesis – Properties – Performance Relationships

“…For example, Zhou et al. [ 194 ] prepared HC from rosewood (pre‐chemically treated or not) at 1100 °C and found that the chemical treatment led to a larger volume of closed pores compared to the untreated HC (i.e., 0.055 cm 3 g −1 vs. 0.039 cm 3 g −1 ). The higher volume of closed pores was related to the breakdown of the fibrous structure of the precursor (i.e., the elimination of hemicellulose/lignin and the partial hydrolysis of cellulose in an alkaline medium), which resulted in the development of closed pores with thinner walls.…”

Interfacial Engineering of Na3V2(PO4)2O2F Cathode for Low-Temperature (−40 °C) Sodium-Ion Batteries

“…When placed in a subzero-temperature environment, the SIBs suffer from severe energy and power losses, resulting in unsatisfactory electrochemical performance, mainly due to the sluggish diffusion kinetics of sodium ions and electrons at LTs. Besides, the interfacial problems including sluggish interfacial electrochemical reaction kinetics, poor interfacial ion storage capacity will continue to be exacerbated at LTs. − It is urgent to exploit appropriate means to improve the interface problem at LTs. The application of interfacial chemical bonding in electrochemical storage and energy conversion systems is developed, therein special bridging bonds of M–X–C (M presents metal elements; X = O, S, N, etc.…”