Tuning Nanopore Structure of Hard Carbon Anodes by Zinc Gluconate for High Capacity Sodium Ion Batteries

Abstract

Hard carbon serves as a highly promising anode material for sodium‐ion batteries due to its stable structure and cost‐effectiveness. Although the hard template method is commonly employed to enhance the sodium storage capacity, the reported process steps are complicated. In this study, we introduced a facile approach by utilizing ZnO as a self‐sacrified template to engineer pore structures with one step for template removal without using harmful chemicals. Our investigations reveal that pretreatment of the material before carbonization can reduce the specific surface area and defect degree of the final hard carbon. When utilized as an anode material, the as‐prepared hard carbon demonstrated a reversible capacity of 334 mAh g−1 at 0.05 A g−1 with an initial Coulombic efficiency of 84%. Even at a high current density of 2 A g−1, the capacity stabilized at 183 mAh g−1 after 1000 continuous cycles. Electrochemical storage behavior and ex‐situ Raman spectroscopy unveiled insights into the potential sodium storage mechanism. These findings present a new approach to enhancing the reversible properties of hard carbon anode materials for high‐performance sodium‐ion batteries

Preparation of Enriched Closed-Pores Hard Carbon for High-Performance Sodium-Ion Batteries by the Poly(vinyl butyral) Template Method

“…Thick deposits on the CFR-PVB6 electrode sheet cause expansion, leading to a loss of reversible capacity of the hard carbon during cycling (Figure S10). Figure d and Table S3 exhibit comparisons in reversible specific capacity of the recently reported works at different current densities. ,− The results show that the samples in this work have an excellent rate performance. The cathode of NaVPO 3 (NVP) is sourced from a commercial product and is coated with poly­(vinylidene fluoride) (PVDF) as a binder, with an NVP:PVDF:Super P ratio of 90:5:5.…”