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_0.2Co_0.2Ni_0.2Cu_0.2Zn_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.

Achieving well-controlled directional steering of liquids is of great significance for both fundamental study and practical applications, such as microfluidics, biomedicine, and heat management. Recent advances allow liquids with different surface tensions to select their spreading directions on a same surface composed of macro ratchets with dual reentrant curvatures. Nevertheless, such intriguing directional steering function relies on 3D printed sophisticated structures and additional polishing process to eliminate the inevitable microgrooves-like surface deficiency generated from printing process, which increases the manufacturing complexity and severally hinders practical applications. Herein, we developed a simplified dual-scale structure that enables directional liquid steering via a straightforward 3D printing process without the need of any physical and chemical post-treatment. The dual-scale structure consists of macroscale tilt ratchet equipped with a reentrant tip and microscale grooves that decorated on the whole surface along a specific orientation. Distinct from conventional design requiring the elimination of microgrooves-like surface deficiency, we demonstrated that the microgrooves of dual-scale structure play a key role in delaying or promoting the local flow of liquids, tuning of which could even enable liquids select different spreading pathways. This study provides a new insight for developing surfaces with tunable multi-scale structures, and also advances our fundamental understanding of the interaction between liquid spreading dynamics and surface topography.