Confining TiO2 Nanotubes in PECVD-Enabled Graphene Capsules Toward Ultrafast K-Ion Storage: In Situ TEM/XRD Study and DFT Analysis

Nano-Micro Letters

Peng Gao¹  Jingsheng Cai²  Xiangguo Wang²  Jingyu Sun²  Yuanlong Shao²  Zhongti Sun²  Nan Wei²  Shixue Dou³  Ran Cai⁴  Feng Xu⁴ 

[1] Beijing Graphene Institute (BGI);College of Energy, Soochow Institute for Energy and Materials InnovationS (SIEMIS), Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University;Institute for Superconducting and Electronic Materials, University of Wollongong;SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University;

关键词: TiO2;    Potassium storage;    In situ TEM;    Plasma-enhanced CVD;    Graphene;   

DOI  :  10.1007/s40820-020-00460-y

来源: DOAJ

【 摘 要 】

Abstract Titanium dioxide (TiO2) has gained burgeoning attention for potassium-ion storage because of its large theoretical capacity, wide availability, and environmental benignity. Nevertheless, the inherently poor conductivity gives rise to its sluggish reaction kinetics and inferior rate capability. Here, we report the direct graphene growth over TiO2 nanotubes by virtue of chemical vapor deposition. Such conformal graphene coatings effectively enhance the conductive environment and well accommodate the volume change of TiO2 upon potassiation/depotassiation. When paired with an activated carbon cathode, the graphene-armored TiO2 nanotubes allow the potassium-ion hybrid capacitor full cells to harvest an energy/power density of 81.2 Wh kg−1/3746.6 W kg−1. We further employ in situ transmission electron microscopy and operando X-ray diffraction to probe the potassium-ion storage behavior. This work offers a viable and versatile solution to the anode design and in situ probing of potassium storage technologies that is readily promising for practical applications.

【 授权许可】

Unknown