Title

Hollow-Carbon-Templated Few-Layered V5S8 Nanosheets Enabling Ultrafast Potassium Storage and Long-Term Cycling

RIS ID

137940

Publication Details

Li, L., Zhang, W., Wang, X., Zhang, S., Liu, Y., Li, M., Zhu, G., Zheng, Y., Zhang, Q., Zhou, T., Pang, W., Luo, W., Guo, Z. & Yang, J. (2019). Hollow-Carbon-Templated Few-Layered V5S8 Nanosheets Enabling Ultrafast Potassium Storage and Long-Term Cycling. ACS Nano, 13 (7), 7939-7948.

Abstract

Due to the abundant potassium resource on the Earth's crust, researchers now have become interested in exploring high-performance potassium-ion batteries (KIBs). However, the large size of K+ would hinder the diffusion of K ions into electrode materials, thus leading to poor energy/power density and cycling performance during the depotassiation/potassiation process. So, few-layered V5S8 nanosheets wrapping a hollow carbon sphere fabricated via a facile hollow carbon template induced method could reversibly accommodate K storage and maintain the structure stability. Hence, the as-obtained V5S8@C electrode enables rapid and reversible storage of K+ with a high specific capacity of 645 mAh/g at 50 mA/g, a high rate capability, and long cycling stability, with 360 and 190 mAh/g achieved after 500 and 1000 cycles at 500 and 2000 mA/g, respectively. The excellent electrochemical performance is superior to the most existing electrode materials. The DFT calculations reveal that V5S8 nanosheets have high electrical conductivity and low energy barriers for K+ intercalation. Furthermore, the reaction mechanism of the V5S8@C electrode in KIBs is probed via the in operando synchrotron X-ray diffraction technique, and it indicates that the V5S8@C electrode undergoes a sequential intercalation (KV5S8) and conversion reactions (K2S3) reversibly during the potassiation process.

Grant Number

ARC/FT150100109, ARC/DP170102406, ARC/DE190100504

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