Engineering Ultrathin Carbon Layer on Porous Hard Carbon Boosts Sodium Storage with High Initial Coulombic Efficiency

Abstract

Hard carbon (HC) has been widely adopted as the anode material for sodium ion batteries (NIBs). However, it is troubled by a low initial Coulombic efficiency (ICE) due to its porous structure. Herein, a graphitized and ultrathin carbon layer coating on HC is proposed to solve this challenge. The as-prepared porous carbon material coated with an ultrathin carbon layer composite (PCS@V@C) exhibits a cavity structure, which is prepared by using bis(cyclopentadienyl) nickel (CP−Ni) as the carbon source for outer coating, glucose carbon spheres as porous carbon, and introducing a silica layer to facilitate the coating process. When utilized as the anode for NIBs, the material shows an ICE increase from 47.1% to 85.3%, and specific capacity enhancement at 0.1 A g −1 from 155.3 to 216.7 mA h g −1 . Moreover, its rate capability and cycling performance are outstanding, demonstrating a capacity of 140.3 mA h g −1 at 10 A g −1 , and a retaining capacity of 225.6 mA h g −1 after 300 cycles at 0.1 A g −1 with the Coulombic efficiency of 100% at the second cycle. The excellent electrochemical performance of the PCS@V@C is attributed to the ultrathin carbon layer, which is beneficial for the formation of a stable solid electrolyte interphase (SEI) film. Therefore, this study provides a feasible surface modification method for the preparation of anode materials for NIBs with high specific capacity and ICE.

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

“…The excellent rate capability and cycling stability of XA-4T-1300 can be attributed to the effective regulation of AC by the pitch. In this study, we compare the specific capacity and ICE of XA-4T-1300 with those of recently reported anode materials for SIBs (Figure f). ,,− The optimized sample XA-4T-1300 in this study exhibits a favorable ICE and specific capacity.…”

“…For XA-4T-1300, the capacity retention is 64.9% after 50 cycles at 100 mA g –1 (Figure c). Despite the extensive research dedicated to developing anode materials for SIBs (Table S6), ,,,− this work still has its advantages. These results all indicate that the composite materials prepared in this study have broad prospects for practical applications.…”

Rapid Carbonization of Anthracite Coal via Flash Joule Heating for Sodium Ion Storage

“…When b approaches 1, charge storage in the cell is mainly controlled by capacitive behavior. When b nears 0.5, it is principally governed by semilinear diffusion processes . The b value was calculated from the linear plot of log( i ) versus log( v ), yielding values of 0.79 for the cathode and 0.7 for the anode.…”

Wedelia chinensis-derived biomass porous carbon as anode material for high performance sodium/potassium ion batteries

“…4c), corresponding to 47.6% of ICE. The ICE is relatively low due to the formation of the solid electrolyte interface (SEI) layer and the occurrence of irreversible side reactions [51]. Except for the irreversible discharge loss in the rst cycle, the GCD curves show slope characteristics without obvious plateau, indicating good electrochemical kinetic behavior of the material [52].…”