Co-free high entropy spinel oxide anode with controlled morphology and crystallinity for outstanding charge/discharge performance in Lithium-ion batteries

Effects of Elemental Modulation on Phase Purity and Electrochemical Properties of Co‐free High‐Entropy Spinel Oxide Anodes for Lithium‐Ion Batteries

“…The impurity phase in 4MV may lead to rapid capacity decay because it could hinder the Li + transport and cause uneven volume variation of the electrode upon charging/discharging. [63,64] A clear morphology re-construction of the 4MV electrode after cycling is evident in Figure 6c. The 4MMg electrode showed good cycling stability till ≈300 cycles.…”

Charge–Discharge Mechanism of High‐Entropy Co‐Free Spinel Oxide Toward Li+ Storage Examined Using Operando Quick‐Scanning X‐Ray Absorption Spectroscopy

“…The reduction and oxidation reaction products are nanoscale, defective, and poorly crystalline, and thus difficult to probe via XRD. [ 16 , 18 , 20 , 43 ] As shown in Figure S3 (Supporting Information), the diffraction peaks of the pristine spinel HEO vanish after the first lithiation process and never recover upon delithiation (defined as discharging in this work). This means that the long‐range lattice ordering was broken.…”

“…Synthesis of Spinel HEO Powder: The HEO sample was synthesized using a surfactant-assisted hydrothermal method. [18] Equimolar (1 mmol) Fe(NO 3 ) 3 •9H 2 O (J. T. Baker, 99%), Ni(NO 3 ) 2 •6H 2 O (Alfa Aesar, 98.5%), Mn(NO 3 ) 2 •6H 2 O (Alfa Aesar, 98.5%), Cr(NO 3 ) 3 •9H 2 O (Alfa Aesar, 98.5%), and Cu(NO 3 ) 2 •2.5H 2 O (Alfa Aesar, 98%) were dissolved in 40 mL of deionized water, followed by the addition of 1.25 mmol (1hexadecyl)trimethylammonium bromide (Alfa Aesar, 98.5%) as a surfactant. 30 mmol urea (UniRegion Bio-Tech, 99%) was then added with continuous stirring to form a homogenous solution.…”

“…[ 14 , 15 ] The entropy‐derived phase stabilization effects can improve electrode reversibility and cycleability. [ 16 , 17 , 18 ] Moreover, the HEO lattice is distorted due to the different sizes of the constituent atoms, which creates a lattice residual stress that can alter material properties. [ 19 ] Rock‐salt‐structure HEO anodes have been proposed since 2018.…”

Kinetically Accelerated Lithium Storage in High‐Entropy (LiMgCoNiCuZn)O Enabled By Oxygen Vacancies

“…In addition, the enrichment of plentiful nanocrystals is observed in the postmortem TEM images (Figure S14, Supporting Information), manifesting that electrochemical cycling may lead to the nanocrystallization of Li-MO. [53] This is conspicuously different from the conventional TMO anodes such as Co 3 O 4 , NiO, ZnO, whose structural evolution after electrochemical cycling has been studied in many literatures. [54][55][56] As shown in Figure 8d, in the first half-cycle, the surface of the TMO anode is composed of agglomerated or sparsely distributed reduced metal particles.…”