Double‐shell and yolk‐shell structured ZnSe ‐carbon nanospheres as anode materials for high‐performance potassium‐ion batteries

Abstract

Transition-metal chalcogenides are prospective anode materials for potassiumion batteries. Herein, crystalline ZnSe nanocrystal-loaded hollow carbon nanospheres (ZnSe-HC) are synthesized by infiltration of zinc nitrate and selenium dioxide into hollow carbon nanospheres and subsequent selenization.The electrochemical reaction mechanism of ZnSe with K-ion is systematically examined by ex-situ X-ray photoelectron spectroscopy and transmission electron microscopy. Two samples with distinctive nanostructures, which are double-shelled hollow structure and yolk-shelled structure, can be fabricated by controlling the selenization temperature, and their K-ion storage performances are compared. The double-shelled ZnSe-HC, which is prepared at a lower temperature, exhibits superior cycling and rate performances to those of the yolk-shelled ZnSe-HC. For double-shelled ZnSe-HC, small ZnSe nanocrystals embedded in the carbon shell and dispersed over the inner carbon shell contribute to the structural stability and fast kinetics during repeated cycles. As a result, the double-shelled ZnSe-HC exhibits a stable cycling performance (400 mA h g À1 at 0.1 A g À1 after 100 cycles) and excellent rate capability (240 mA h g À1 at 3.0 A g À1 ).

Se/N co-doped carbon nanorods for potassium ion storage

“…2d), there are three peaks corresponding to C–C/CC (284.8 eV), C–O (286.1 eV) and CO (288.8 eV) in the CRs, SeCRs and SeNCRs. 24 Additionally, compared to the C 1s spectra of the CRs and SeCRs, as shown in Fig. 2d, a new peak at 285.3 eV that can be attributed to C–N is observed for SeNCRs.…”

“…2d), there are three peaks corresponding to C-C/CvC (284.8 eV), C-O (286.1 eV) and CvO (288.8 eV) in the CRs, SeCRs and SeNCRs. 24 Additionally, compared to the C 1s spectra of the CRs and Scheme 1 Schematic for the synthesis process of the SeNCRs.…”

Research progress on ZnSe and ZnTe anodes for rechargeable batteries

“…34,54,55 The electrochemical reaction mechanism for potassium storage resembles that of sodium in ZnSe-based materials, forming K 2 Se and KZn 13 . 33,35,56,57 For example, the ex situ XRD and HRTEM characterization studies clarify that the electrochemical K storage mechanism for ZnSe electrode materials (Fig. 3), selenide intermediate (K 2 Se 3 , other references reported as K 2 Se) and elemental Se are clearly detected in the discharge-charge process, and cubic phase ZnSe can be fully recovered thereafter.…”

“…3), selenide intermediate (K 2 Se 3 , other references reported as K 2 Se) and elemental Se are clearly detected in the discharge-charge process, and cubic phase ZnSe can be fully recovered thereafter. 33,35,56,57 In regards to Na/K-storage for bimetallic selenide compounds, the reaction mechanism is somewhat similar to that for Li-storage. 52 Based on these results of mechanism investigation, new opportunities will surely open up for the rational and facile design and synthesis of advanced materials and electrodes for electrochemical energy storage devices.…”

“…Some similar structures are also reported, e.g., a ZnSe nanoparticle@N-doped hollow polyhedron compo-site (ZnSe NP@NHC), 47 and double-shell or yolk-shell structured ZnSe-C nanospheres (ZnSe-HC). 57 The introduction of 2D/3D conductive frameworks is of great importance to realize ideal electron/ion transport in electrochemical energy storage systems. 61,93,94,133 Ruan et al designed a "dual-carbon-confined" structure with N-doped carbon-coated ZnSe nanoparticles embedded in 2D rGO by coprecipitation and self-assembly with the assistance of freezedrying followed by simultaneous pyrolysis, reduction and selenization (Fig.…”