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Robust Pseudocapacitive Sodium Cation Intercalation Induced by Cobalt Vacancies at Atomically Thin Co 1− x Se 2 /Graphene Heterostructure for Sodium‐Ion Batteries
Author(s) -
Yuan Ding,
Dou Yuhai,
Tian Yuhui,
Adekoya David,
Xu Li,
Zhang Shanqing
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202106857
Subject(s) - pseudocapacitance , materials science , intercalation (chemistry) , heterojunction , graphene , vacancy defect , electrode , chemical engineering , density functional theory , cobalt , energy storage , nanotechnology , inorganic chemistry , supercapacitor , optoelectronics , electrochemistry , chemistry , thermodynamics , crystallography , computational chemistry , metallurgy , power (physics) , physics , engineering
Electronic structure engineering on electrode materials could bring in a new mechanism to achieve high energy and high power densities in sodium ion batteries. Herein, we design and create Co vacancies at the interface of atomically thin CoSe 2 /graphene heterostructure and obtain Co 1− x Se 2 /graphene heterostructure electrode materials that facilitate significant Na + intercalation pseudocapacitance. Density functional theory (DFT) calculation suggests that the Na + adsorption energy is dramatically increased, and the Na + diffusion barrier is remarkably reduced due to the introduction of Co vacancy. The optimized electrode delivers a superior capacity of 673.6 mAh g −1 at 0.1 C, excellent rate capability of 576.5 mAh g −1 at 2.0 C and ultra‐long life up to 2000 cycles. Kinetics analysis indicates that the enhanced Na + storage is mainly attributed to the intercalation pseudocapacitance induced by Co vacancies. This work suggests that the creation of cation vacancy could bestow heterostructured electrode materials with pseudocapacitive Na + intercalation for high‐capacity and high‐rate energy storage.