Heterostructures of 2D Molybdenum Dichalcogenide on 2D Nitrogen‐Doped Carbon: Superior Potassium‐Ion Storage and Insight into Potassium Storage Mechanism

Abstract

To meet the requirements of the rapid development of large-scale energy storage systems, "Beyond Li-ion battery (LIB)" systems are attracting more and more attention. [1][2][3][4][5] Among various alkali metals ion batteries, potassium-ion batteries (KIBs) exhibit many advantages for large-scale energy storage system applications including: [6,7] 1) the low manufacturing costs because of the natural abundance of their raw materials; 2) much lower redox potential of K/K + (−2.93 V vs standard hydrogen electrode) leading to higher open-circuit voltage and higher energy density compared with sodiumion batteries (SIBs). [8][9][10] According to the advantages and properties of low production costs and high energy density, the KIB is considered as a promising energy storage system for large-scale energy storage application. However, KIBs suffer from inferior cyclic stability and insufficient power density resulting from the structure collapse of electrode materials due to the bigger K + Constructing 2D heterostructure materials by stacking different 2D materials can combine the merits of the individual building blocks while eliminating their shortcomings. Dichalcogenides are attractive anodes for potassium-ion batteries (KIBs) due to their high theoretical capacity. However, the practical application of dichalcogenide is greatly hampered by the poor electrochemical performance due to sluggish kinetics of K + insertion and the electrode structure collapse resulting from the large K + insertion. Herein, heterostructures of 2D molybdenum dichalcogenide on 2D nitrogen-doped carbon (MoS 2 , MoSe 2 -on-NC) are prepared to boost their potassium storage performance. The unique 2D heterostructures possess built-in heterointerfaces, facilitating K + diffusion. The robust chemical bonds (CS, CSe, CMo bonds) enhance the mechanical strength of electrodes, thus suppressing the volume expansion. The 2D N-doped carbon nanosheets interconnected as a 3D structure offer a fast diffusion path for electrons. Benefitting from these merits, both the MoS 2 -on-NC and the MoSe 2 -on-NC exhibit unprecedented cycle life. Moreover, the electrochemical reaction mechanism of MoSe 2 is revealed during the process of potassiation and depotassiation.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.

MOF-Derived CoSe2@N-Doped Carbon Matrix Confined in Hollow Mesoporous Carbon Nanospheres as High-Performance Anodes for Potassium-Ion Batteries

“…Potassium-ion batteries (KIBs) have recently attracted considerable attention for their high energy densities and the abundant availability of potassium as a raw material [1][2][3]. Thus, KIBs are being positioned as an alternative energy storage system to lithium-ion batteries (LIBs), which are currently the dominant power sources for electric vehicles and portable electronic devices.…”

Recent Advances in Heterostructured Anode Materials with Multiple Anions for Advanced Alkali‐Ion Batteries

“…[56,77,81,82] As a result, numerous heterointerfaces and ion reservoirs are formed between the materials, which is beneficial for enhancing the electrochemical kinetics of electrode materials. [83][84][85] In addition, multi-anion electrodes undergo multi-step discharge and charge processes, and higher reversible capacities compared to single-anion counterparts have been observed in many cases. [64,[86][87][88][89][90] Furthermore, it has been reported that the presence of different materials during galvanostatic charge and discharge processes helps alleviate the volume change of the electrode materials because the compounds undergo electrochemical processes at different potentials; materials that are inactive at a certain potential help release the strain received by the other material, and consequently, the cycle life of the electrodes can be prolonged.…”

Atomically Thin Nanosheets Confined in 2D Heterostructures: Metal‐Ion Batteries Prospective

“…[42] Although research on electrochemical characteristics and energy storage mechanisms of 2D heterostructures is in its early phase, some recently reported 2D heterostructures could deliver superior performances as an electrode of MIBs. [48][49][50] Based on well-known individual characteristics of 2DMs, their heterostructures can be rationally designed for highperformance MIBs electrodes. In this regard, highly conducting 2DMs such as graphene in heterostructures with high energy density TMDs or MXenes enabled a robust electronic and ionic transport as compared to its counterparts.…”

“…Rate capability of MoSe 2 , graphene/MoS 2 , and graphene/MoSe 2 and charge/discharge results of graphene/MoSe 2 at different current densities. Reproduced with the permission [48]. Copyright 2020, Wiley-VCH.…”