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36. Lignite‐Based Hierarchical Porous C/SiOx Composites as High‐Performance Anode for Potassium‐Ion Batteries.

Author

Yang, Zexu, Zhao, Shouwang, Jiao, Rongji, Hao, Gengyu, Liu, Yunying, He, Wenxiu, Chen, Jingwei, Jia, Guixiao, Cui, Jinlong, and Li, Shaohui

Subjects
ANODES, TRANSMISSION electron microscopy, POTASSIUM ions, LITHIUM-ion batteries, STORAGE batteries
Abstract

Silicon oxide (SiOx, 0 < x ≤ 2) has been recognized as a prominent anode material in lithium‐ion batteries and sodium‐ion batteries due to its high theoretical capacity, suitable electrochemical potential, and earth abundance. However, it is intrinsically poor electronic conductivity and excessive volume expansion during potassiation/depotassiation process hinder its application in potassium‐ion batteries. Herein, we reported a hierarchical porous C/SiOx potassium‐ion batteries anode using lignite as raw material via a one‐step carbonization and activation method. The amorphous C skeleton around SiOx particles can effectively buffer the volume expansion, and improve the ionic/electronic conductivity and structural integrity, achieving outstanding rate capability and cyclability. As expected, the obtained C/SiOx composite delivers a superb specific capacity of 370 mAh g−1 at 0.1 A g−1 after 100 cycles as well as a highly reversible capacity of 208 mAh g−1 after 1200 cycles at 1.0 A g−1. Moreover, the potassium ion storage mechanism of C/SiOx electrodes was investigated by ex‐situ X‐ray diffraction and transmission electron microscopy, revealing the formation of reversible products of K6.8Si45.3 and K4SiO4, accompanied by generation of irreversible K2O after the first cycle. This work sheds light on designing low‐cost Si‐based anode materials for high‐performance potassium‐ion batteries and beyond. [ABSTRACT FROM AUTHOR]

Published
2024
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37. Pyridine N‐Modulated Adsorption Equilibrium of Highly Dispersed Atomic W‐P Clusters toward Advanced Potassium‐Ion Hybrid Capacitors.

Author

Hu, Shuxiao, Chu, Shile, Zeng, Fanyan, Pan, Yang, Liu, Baoquan, He, Wenxiu, Ma, Dui, Xie, Meilan, and Luo, Shenglian

Subjects
ATOMIC clusters, CAPACITORS, PYRIDINE, ELECTRON distribution, ENERGY density, FULLERENES, ELECTRONEGATIVITY, METAL clusters
Abstract

Improving the atomic utilization of storage sites and developing isotropic transport characteristics become crucial to enhance the performance of potassium‐ion hybrid capacitors (PIHCs), and the disordered strategy and coordination modulation of the electrodes can satisfy the above structure‐activity requirements. Herein, the highly dispersed atomic W‐P clusters are chosen as a platform for the electronic restructuring. Studies and calculations indicate that replacing O in W‐O2/P2 with pyridine N can modulate the electron distribution and electronegativity, and enrich the edge‐dangling bonds of the amorphous clusters (W‐N2/P2), resulting in proper adsorption equilibrium and high affinity for K+ storage. In addition, the clusters have isotropic and bulk‐phase‐indifferent fast ion storage, and in situ protection of carbon nanosheets can provide stable support for ion storage and electron transfer in the clusters. As an anode, the composite (W‐N/P@C) exhibits superior storage properties of K+ (reversible capacity of 181.6 mAh g−1 after 3000 cycles at 5.0 A g−1), with high energy density (163.7 Wh Kg−1) at the high‐power output (3500 W Kg−1) in PIHCs. This work systematically delineates the effects of disordered design and pyridine N‐coordination on energy storage, and provides new research ideas for studying high‐performance PIHCs. [ABSTRACT FROM AUTHOR]

Published
2024
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