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

Abstract

Amorphous carbon shows great potential as an anode material for high-performance potassium-ion batteries; 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 with highly disordered structure, the meso-C with Zn-catalyzed short-range ordered structure enables more K+ to reversibly intercalate into the graphitic 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.

Wire-in-Wire TiO2/C Nanofibers Free-Standing Anodes for Li-Ion and K-Ion Batteries with Long Cycling Stability and High Capacity

“…As one of the most efficient energy storage devices, flexible Li-ion batteries (LIBs) gradually become all-important in the field of energy storage. Recently, K-ion batteries (KIBs) have attracted masses of attention because of their abundant raw materials in natural resources, similar working mechanisms, and approximate standard reduction potential (lithium: − 3.04 V vs. E 0 , potassium: − 2.93 V vs. E 0 ) compared with LIBs [3][4][5]. The flexible electrodes with high-performance are essential for the applications of flexible advanced secondary batteries.…”

Recent Progress on Asymmetric Carbon- and Silica-Based Nanomaterials: From Synthetic Strategies to Their Applications

“…Carbon-and silica-based nanoparticles, especially carbon nanoparticles, have become the main electrode materials due to the good conductivity, large surface area, and excellent electrochemical stability [159][160][161][162][163][164][165]. Also, the rational design of materials structure can effectively improve its energy storage performance [166][167][168]. The traditional hollow structure is one of the most ideal structures because of its tunable inner cavity, which can effectively alleviate the large-volume expansions during charge-discharge processes.…”

Promise and reality of practical potassium‐based energy storage systems

“…Benefiting from the mesoporous structure with reduced specific surface area by 31.5 times and less density of defects, the meso-C generated a high initial Coulombic efficiency up to 76.7%. 72…”

“…Guo and co‐worker achieved mesoporous carbon (meso‐C) nanowires with interconnected framework via pore engineering. Benefiting from the mesoporous structure with reduced specific surface area by 31.5 times and less density of defects, the meso‐C generated a high initial Coulombic efficiency up to 76.7% 72 . Table 2 summarizes the electrochemical performance of representative PIBs with designed carbon morphologies 64,73‐78 …”