Enhanced Interfacial Magnetization is Responsible for the Negative Capacity Fading of Cobalt Ditelluride Anodes for Lithium Storage

Abstract

In lithium‐ion batteries (LIBs), the stabilized capacities of transition metal compound anodes usually exhibit higher values than their theoretical values due to the interfacial charge storage, the formation of reversible electrolyte‐derived surface layer, or interfacial magnetization. But the effectively utilizing the mechanisms to achieve novel anodes is rarely explored. Herein, a novel nanosized cobalt ditelluride (CoTe2) anodes with ultra‐high capacity and long term stability is reported. Electrochemical tests show that the lithium storage capacity of the best sample reaches 1194.7 mA h g−1 after 150 cycles at 0.12 A g−1, which increases by 57.8% compared to that after 20 cycles. In addition, the sample offers capacities of 546.6 and 492.1 mA h g−1 at 0.6 and 1.8 A g−1, respectively. During cycles, CoTe2 particles (average size 20 nm) are gradually pulverized into the smaller nanoparticles (<3 nm), making the magnetization more fully due to the larger contact area of Co/Li2Te interface, yielding an increased capacity. The negative capacity fading is observed, and verified by ex situ structural characterizations and in situ electrochemical measurements. The proposed strategy can be further extended to obtain other high‐performance ferromagnetic metal based electrodes for energy storage applications.

Electronically modulated bimetallic telluride nanodendrites atop 2D nanosheets using a vanadium dopant enabling a bifunctional electrocatalyst for overall water splitting

“…4c) shows a couple of peaks corresponding to Co–Te (781.01 eV and 796.95 eV) and satellite peaks (785.94 eV and 802.78 eV) with a spin–orbit splitting energy (Δ E = E (Co2p 1/2 ) − E (Co2p 3/2 ) ) of 15.98 eV. 44 The peak position of each deconvoluted peak of Co 2p for V-CoTe 2 /MoTe 2 @CC shifted toward a slightly greater BE than that of CoTe 2 /MoTe 2 @CC. V dopants lead to charge transfer on the surface of the sample, leading to a blueshift and resulting in a decrease in the energy barrier, which is beneficial for OER activity.…”

Emerging 2D Cobalt Telluride (CoxTey): from Theory to Applications

“…Under scanning electron microscope and elemental energy dispersive spectroscopy, the films were consisted by many nanostructured domains with lateral dimension no more than 100 nm and the relative atomic ratio of Co: Te were determined to be 46: 54 and 32: 67, respectively. [ 74 ] Parallel to this, mechanochemical synthesis, [ 22 ] tellurization [ 75 ] and polyol reduction of ultrathin Te nanostructures [ 17 ] were excavated to selectively fabricate 2D Co x Te y with desired lattice structures and phases. More efforts in controlling the phase purity, crystallinity and the lateral dimension, may significantly boost the scientific advance of cobalt telluride and subsequent applications.…”