Ultrafast high-temperature sintering of high-entropy oxides with refined microstructure and superior lithium-ion storage performance

Abstract

High-entropy oxides (HEOs) have received significant attention because of their tunable mechanical properties and wide range of functional applications. However, the conventional method used for sintering HEOs requires prolonged processing time, which results in excessive grain growth, thereby compromising their performance. Here, an ultrafast high-temperature sintering (UHS) strategy was adopted, and rock-salt composite (Mg 0.2 Co 0.2 Ni 0.2 Cu 0.2 Zn 0.2 )O was selected as model materials. Experimental parameters were tuned to illustrate the influence of applied current and soaking time on the densification process and resulting grain size. Additionally, the electrochemical performance of UHS-synthesized microparticles as anode materials in lithium-ion batteries was investigated. The results show that the ultrafast heating rate results in fine grains with a diameter of 6-8 μm and density of 95%, which are much smaller and similar to those obtained using the conventional sintering method (25 μm and 96%). Moreover, the high surface area and reactivity of the microparticles, as well as their sluggish diffusion effect and structural stability, contribute to outstanding performance with high capacity (336 mA•h/g at 1 A/g) and ultralong cyclability (1000 cycles). This novel technique offers valuable insights into the densification process of HEOs and other materials and can thus broaden their application range.

High‐Entropy Argyrodite‐Type Sulfide Electrolyte with High Conductivity and Electro‐Chemo‐Mechanical Stability for Fast‐Charging All‐Solid‐State Batteries

“…[14,15] This HE-concept emerges from HE-alloys and has recently been extended to HE-ceramics, including cathode and anode materials for energy storage. [16][17][18] However, very few studies have investigated HE-solid electrolytes. Considering that materials of higher entropy enable joint solubility of ions with large ionic radius differences and consequently greater chemical disorder, the HE-concept holds great potential in the design of high-performance argyrodite sulfide electrolytes.…”

Identifying lithium difluoro(oxalate)borate as a multifunctional electrolyte additive to enable high-voltage Li4Ti5O12 lithium-ion batteries

“…Lithium-ion batteries (LIBs) have been developed for a wide range of applications, such as electronic devices, electric vehicles, and renewable energy storage systems, in which anode materials are an indispensable component in determining the performance of LiBs. [1][2][3] Among various anode materials of LIBs, spinel lithium titanate (Li 4 Ti 5 O 12 , LTO) is considered excellent owing to its promising properties of high safety, cycling stability, thermal stability, and environmental friendliness. [4][5][6] Nevertheless, the large-scale practical applications of LTO batteries have been severely obstructed by the shortcomings of their LTO anode, i.e., poor electronic conductivity and Li + diffusion, severe gas generation, and especially low energy density.…”