arXiv subjects

Bao Yuan

Publications and source records attributed to Bao Yuan.

4 recordsLinked to original sources

arXiv2026

Transforming Acidic Corrosion and Embrittlement into a Hydrogen-Trapping Cage

The vision of a hydrogen economy demands efficient platforms to close the gap between sustainable proton sources and solid-state hydrogen carriers. Metal hydrides serve as key carriers, yet their synthesis remains constrained by the energy-intensive use of high-pressure H2, which fragments the hydrogen chain. Here, we overturn this paradigm by transforming two classic degradation mechanisms, acidic corrosion and hydrogen embrittlement, into a constructive materials-design strategy. We demonstrate that synergistic control of these processes in acid enables the in-situ engineering of a "hydrogen-trapping cage" (HTC) microstructure within metals. Composed of a dense defect network, this cage directly captures and stabilizes protons as hydrides under mild conditions, guided by the universal criterion |DeltaPeq| > DeltaPph. Using this platform, we synthesize over 20 hydrides, including challenging targets such as LiH and NaH, and showcase its functional power with a cage-rich titanium hydride electrocatalyst. This catalyst achieves an exceptional current density of 1.07 A cm-2 for nitrate-to-ammonia conversion, attributed to rapid H- transport within the engineered cage. This work establishes a transformative "failure-to-function" paradigm, delivering an integrated platform that unifies hydrogen capture, stabilization, and conversion.

cond-mat.mtrl-sci↗

arXiv2024

Pressure tunable magnetic skyrmion phase in Co8Zn8Mn4 single crystals

In a magnetic skyrmion phase, magnetic moments form vortex-like topological textures which are of both fundamental and industrial interests. In $β$-Mn-type Co-Zn-Mn alloys, chrial magnetic skyrmions emerge above room temperature, providing a unique system for studying the skrymion physics and exploring spintronics applications. However, the magnetic skyrmion phase is typically confined in a narrow and limited temperature ($T$) and magnetic field ($H$) range. Here, we demonstrate that hydrostatic pressure can expand the skyrmion phase in the $T-H$ phase diagram of single-crystalline Co$_8$Zn$_8$Mn$_4$. At ambient pressure, signatures of skyrmions are seen within $T\sim302-308$ K and $H\sim50-100$ Oe. Applying a moderate pressure of 6 kbar extends this range to $T\sim300-310$ K and $H\sim50-150$ Oe. However, further escalation of pressure to 10 kbar results in a slight contraction of the skyrmion phase. These findings underscore the sensitivity of the skyrmion phase in Co$_8$Zn$_8$Mn$_4$ to external pressures, and hint at the potential of strain engineering, particularly in $β$-Mn-type Co-Zn-Mn thin films, as a promising avenue to customize the skyrmion phase.

cond-mat.mtrl-sci↗

arXiv2021

Ultrasensitive barocaloric material for room-temperature solid-state refrigeration

Solid-state refrigeration based on caloric effects is an energetically efficient and environmentally friendly technology, which is deemed as a potential alternative to the conventional vapor-compression technology. One of the greatest obstacles to the real application is the huge driving fields. Here, we report a giant barocaloric effect in inorganic NH4I with maximum entropy changes of ΔS_BCE^max ~89 J K-1 kg-1 around room temperature, associated with the orientationally order-disorder phase transition. The phase transition temperature, Tt, varies dramatically with pressure in a rate of dTt/dP ~0.81 K MPa-1, which leads to a very much small saturation driving pressure of ΔP ~20 MPa, an unprecedentedly large caloric strength of |ΔS_BCE^max/ΔP| ~4.45 J K-1 kg-1 MPa-1, as well as a broad temperature window of ~68 K under an 80 MPa driving pressure. Comprehensive characterization of the crystal structure and dynamics by neutron scattering measurements reveals a strong reorientation-vibration coupling that is responsible for the large pressure sensitivity of Tt. This work is expected to advance the practical application of barocaloric refrigeration.

cond-mat.mtrl-sci↗

arXiv2021

Barocaloric thermal batteries

Nowadays the world is facing a prominent paradox regarding thermal energy. The production of heat accounts for more than 50% of global final energy consumption while the waste heat potential analysis reveals that 72% of the global primary energy consumption is lost after conversion mainly in the form of heat. Towards global decarbonization, it is of vital importance to establish a solution to thermal energy utilization under full control. Here, we propose and realize an unprecedented concept -- barocaloric thermal batteries based on the inverse colossal barocaloric effect of NH4SCN. Thermal charging is initialized upon pressurization through an order-to-disorder phase transition below 364 K and in turn the discharging of 43 J g-1, which are eleven times more than the input mechanical energy, occurs on demand at depressurization at lower temperatures. The discharging is also manifested as a directly measured temperature rise of 12 K. The thermodynamic equilibrium nature of the pressure-restrained heat-carrying phase guarantees stable storage and/or transport over a variety of temporal and/or spatial scales. The barocaloric thermal batteries reinforced by their solid microscopic mechanism are expected to significantly advance the ability to take advantage of waste heat.

cond-mat.mtrl-sci↗