15August2020

Nano-Micro Letters

Engineering Mesoporous Structure in Amorphous Carbon Boosts Potassium Storage with High Initial Coulombic Efficiency

Ruiting Guo1, Xiong Liu1, Bo Wen1, Fang Liu1, Jiashen Meng1, Peijie Wu1, Jinsong Wu1, Qi Li1, *, Liqiang Mai1, 2, *

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Nano-Micro Lett. (2020) 12: 148

First Online: 13 July 2020 (Article)

DOI:10.1007/s40820-020-00481-7

*Corresponding author. E-mail: qi.li@whut.edu.cn (Qi Li); mlq518@whut.edu.cn (Liqiang Mai)

 

Abstract

 


Toc

Amorphous carbon shows great potential as anode material for high-performance potassium-ion batteries (PIBs); however, its abundant defects or micropores generally capture K ions, thus resulting in high irreversible capacity with low initial coulombic efficiency (ICE) and limited practical application. Herein, pore engineering via a facile self-etching strategy is applied to achieve mesoporous carbon (meso-C) nanowires with interconnected framework. Abundant and evenly distributed mesopores could provide short K+ pathways for its rapid diffusion. Compared to microporous carbon (micro-C) with highly disordered structure, the meso-C with Zn-catalyzed short-range ordered structure enables more K+ to reversibly intercalate into the graphited layers. Consequently, the meso-C shows an increased capacity by ~100 mAh g-1 at 0.1 A g-1, and the capacity retention is 70.7% after 1000 cycles at 1 A g-1. Multiple in/ex situ characterizations reveal the reversible structural changes during the charging/discharging process. Particularly, benefiting from the mesoporous structure with reduced specific surface area by 31.5 times and less defects, the meso-C generates less irreversible capacity with high ICE up to 76.7%, one of the best reported values so far. This work provides a new perspective that mesopores engineering can effectively accelerate K+ diffusion and enhance K+ adsorption/intercalation storage.


 

Keywords

Potassium-ion battery; Mesopores engineering; Storage mechanism; Initial coulombic efficiency

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