In Situ Revealing the Electroactivity of PO and PC Bonds in Hard Carbon for High‐Capacity and Long‐Life Li/K‐Ion Batteries
By Yong Qian, Song Jiang, Yang Li, Zheng Yi, Jie Zhou, Tieqiang Li, Yingzi Han, Yusong Wang, Jie Tian, Ning Lin and 1 more. Advanced Energy Materials, 2019
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The low capacity and unsatisfactory rate capability of hard carbon still restricts its practical application for Li/K‐ion batteries. Herein, a low‐cost and large‐scale method is developed to fabricate phosphorus‐doped hard carbon (PHC‐700) by crosslinking phosphoric acid and epoxy resin and followed by annealing at 700 °C. H3PO4 acts not only as a crosslinker to solidify epoxy resin for promoting the degree of graphitization and lowering the specific surface area, but also as phosphorus source for forming PC and PO bonds, thus providing more active sites for Li/K storage. As a result, the PHC‐700 electrode delivers a highly reversible capacity of 1294.8 mA h g−1 at 0.1 A g−1 and a capacity of 214 mA h g−1 after 10 000 cycles at 10 A g−1. As for potassium‐ion batteries, PHC‐700 exhibits a reversible capacity of 381.9 mA h g−1 at 0.1 A g−1 and a capacity of 260 mA h g−1 after 1000 cycles at 0.2 A g−1. In situ Raman and in situ NMR measurements reveal that the P‐containing bonds can enhance the adsorption to alkali metal ions, and the PC bond can participate in electrochemical redox reaction by forming Lix PCy . Additionally, P‐doped hard carbon shows better structural/interfacial stability for improved long‐term cycling stability.
Subfields: Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials
View Paper: https://www.semanticscholar.org/paper/f883c51c60807da23551af4fd82bec246b8aa0cd