Hui Gao

The Hong Kong Polytechnic University | PolyU · Department of Applied Biology and Chemical Technology

The rapid increase in lithium‐ion battery (LIB) production, fueled by the rise of electric vehicles, highlights significant challenges in managing end‐of‐life LIBs, particularly regarding environmental impact and waste management. Traditional recycling methods, such as pyrometallurgical and hydrometallurgical processes, are energy‐intensive and con...

Magnetite (Fe3O4) has become a potential anode material in lithium ion batteries (LIBs) because of its high theoretical capacity and low cost, but is impeded for application by its low conductivity and large volume change during cycling. Herein, the Fe3O4@C-500 composite was fabricated via the one-step pyrolytic carbonization of commercial ammonium...

Alloy-type anodes are the most promising candidates for sodium-ion batteries (SIBs) due to their impressive Na storage capacity and suitable voltage platform. However, the implementation of alloy-type anodes is significantly hindered by their huge volume expansion during the alloying/dealloying processes, which leads to their pulverization and deta...

Lithium metal anode has shown great potentials for achieving high energy density due to its high theoretical capacity and low redox potential, but its application is impeded by the dendrite proliferation and unstable solid electrolyte interface. Herein, three-dimensional (3D) porous Cu current collectors were fabricated via the combination of paint...

Potassium‐ and sodium‐ion batteries (PIBs and SIBs) have great potential as the next‐generation energy application owing to the natural abundance of K and Na. Antimony (Sb) is a suitable alloying‐type anode for PIBs and SIBs due to its high theoretical capacity and proper operation voltage; yet, the severe volume variation remains a challenge. Here...

Rechargeable magnesium ion batteries (MIBs) have attracted increasing interest due to abundant reserves, high theoretical specific capacities and safety. However, the incompatibility between Mg metal and conventional electrolytes, among the most serious challenges, restrains their development. Replacing Mg metal with alloy-type anodes offers an eff...

Sodium ion batteries (SIBs) and potassium ion batteries (PIBs) are promising post-lithium candidates for grid-scale energy storage, and understanding of the Na/K chemistry is crucial for the development of advanced electrode materials. Herein, a nanoporous indium-bismuth (np-InBi) alloy was fabricated by chemical dealloying of a ternary Mg-In-Bi pr...

Sn-based anodes for magnesium ion batteries (MIBs) arouse considerable interests, but are restrained by severe failure associated with poor electrochemical reactivity and massive volume changes during cycling. Herein, a multiphase alloying strategy is proposed to improve the electrochemical performance of Sn-based anodes by introducing an active Bi...

InSb alloy is a promising candidate for sodium/potassium ion batteries (SIBs/PIBs) but challenged with achieving high performance by dramatic volumetric changes. Herein, nanoporous (np)-InSb with dual-scale phases (cubic/hexagonal (C/H)-InSb) was fabricated by chemical dealloying of ternary Mg-In-Sb precursor. Operando X-ray diffraction (XRD) and e...

Germanium (Ge) has become a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity and decent electron/ion conductivity, but it exhibits inferior lifespan caused by dramatic volume variations during the (de)lithiation process. Herein, hierarchically, nanoporous Ge (np-Ge) was fabricated by the combination of...

Engineering Sb-based anode materials is the key to enhance their electrochemical performance for sodium ion batteries (SIBs) by solving the issues of the rapid capacity decay and poor rate capability. In this work, a nanoporous NiSb alloy (np-NiSb) with a three-dimensionally interconnected ligament-channel structure was synthesized by a facile deal...

Bi-Sb alloys are appealing anode materials for potassium ion batteries (PIBs) but challenged by their enormous volumetric variation during operation. Herein, a facile one-step dealloying protocol was devised and utilized to prepare the Bi-Sb alloys that manifest an exotic bicontinuous hierarchical nanoporous (np) microstructure ideal for volume-cha...

Rechargeable magnesium ion batteries (MIBs) have aroused great interests, but their development is restrained by the incompatibility of Mg metal anodes with conventional electrolytes. Replacing Mg metal with alloy anodes is a promising strategy to address this incompatibility issue. Based on phase engineering, we designed and fabricated a biphase P...

Na3V2(PO4)3 owns stable three-dimensional open framework and delivers a theoretical capacity of 117.6 mAh/g with a voltage plateau at 3.4 V (vs. Na+/Na). However, the voltage plateau at 1.6 V (vs. Na+/Na) corresponding to the V2+/V3+ redox couple can also deliver a theoretical capacity of 59 mAh/g. Herein, the operating voltage window of Na3V2(PO4)...

Tin (Sn)-based anodes attract extensive attention for magnesium ion batteries however challenges and issues exist, such as relatively difficult alloying reaction, sluggish diffusion kinetics and rapid capacity decay. Herein, we introduce a second phase of bismuth (Bi) with varying contents into Sn via magnetron co-sputtering and get insight into ho...

Sb is a promising anode for sodium ion batteries (SIBs) but held back from practical application owing to its pulverization induced by dramatic volumetric variation. Herein, we propose a simple pressure-induced regulation strategy to efficiently refine nanoscale column-channel architecture of Sb layer by magnetron sputtering, which is easily manipu...

Acidic proton exchange membrane water electrolysis is a prospective energy conversion technology for future hydrogen production. However, its wide application is limited by the excessive dependence of oxygen evolution reaction on precious metals at anode. To address this issue, herein, we report a class of IrM (M = Ni, Co, Fe) catalysts with dilute...

The low capacity of traditional graphite (372 mAh g⁻¹) greatly limits its development as electrode material for future applications, and seeking new anode material is becoming extremely urgent in order to meet the increasing demands. In this work, flexible, self-supporting CuGa2 films are fabricated by simply painting liquid Ga onto commercial Cu f...

The understanding of reaction mechanisms of electrode materials is of significant importance for the development of advanced batteries. The LiMn2O4 cathode has a voltage plateau around 2.8 V (vs. Li⁺/Li), which can provide an additional capacity for Li storage, but it suffers from a severe capacity degradation. In this study, operando X-ray diffrac...

Developing advanced electrocatalysts with low overpotential and long lifetime towards oxygen evolution reaction (OER) is essential and challengeable for the storage and conversion of renewable energy on a large scale. Herein, novel hybrid Ni(OH)2/[email protected] (x:y = 2:1, 1:1, and 1:2) nanosheet catalysts were rationally designed and synthesize...

Rechargeable magnesium batteries have huge potential for applications in large scale energy storage systems due to their low cost and abundant sources. Nevertheless, not much attention has been paid to the development of alternative anodes for magnesium ion batteries (MIBs). Herein, we demonstrate a scalable strategy to fabricate bismuth (Bi)-tin (...

To improve the electrochemical performance of metal-based anodes for sodium ion batteries (SIBs), predominate efforts are focused on nanoporous architecture, metallic alloys, and composites with conductive substrate. Herein, we for the first time propose a novel channels-enhanced strategy to promote the Na storage performance of alloying-type anode...

Among various efficient electrocatalysts for water splitting, CoFe and NiFe-based oxides/hydroxides are typically promising candidates thanks to their extraordinary activities towards oxygen evolution reaction (OER). However, the endeavor to advance their performance towards overall water splitting has been largely impeded by the limited activities...

Magnesium ion batteries are emerging as promising alternatives to lithium ion batteries because of their advantages including high energy density, dendrite-free features and low cost. Nevertheless, one of the major challenges for magnesium ion batteries is the kinetically sluggish magnesium insertion/extraction and diffusion in electrode materials....

Herein, we propose a liquid metal-assisted dealloying strategy to transform bulk metals into metallic nanostructures. Through dealloying of gallium (Ga)-based alloys, nanoporous metals with different dimensions (0D Au, 1D Ag and 2D Cu) were successfully fabricated. Moreover, the sacrificial element (Ga) was efficiently recycled in the form of liqui...

Li metal anode has high capacity and low potential, however, many intrinsic problems such as the growth of Li dendrite hamper the development of Li metal batteries. Herein, we proposed a scalable approach to construct a three-dimensional (3D) porous structure on commercial Cu foil through a liquid Ga-induced alloying-dealloying strategy. The porous...

Antimony (Sb) has captured extensive attention as a promising anode for sodium ion batteries (SIBs) due to its high theoretical capacity and moderate sodiated potential, but is held back for practical applications owing to its pulverization induced by dramatic volumetric variations during (de)sodiation process. Herein, we report a core-shell Sb@Co(...

Developing advanced electrode materials and understanding their reaction mechanisms are two crucial issues for development of high-performance sodium ion batteries (SIBs). Herein, we synthesized a bimetallic single-phase nanoporous (NP) SnSb alloy with a bicontinuous ligament-channel structure through elaborate design of ternary Mg-Sn-Sb precursor...

Developing highly efficient and earth‐abundant electrocatalysts is urgent for oxygen evolution reaction (OER), and layered double hydroxides (LDHs) show great potentials as advanced electrocatalysts toward OER. However, the catalytic activity of LDHs is normally limited by their poor electronic conductivity and low electrochemical active areas. Her...

Pt-based nanomaterials have been widely investigated as efficient electrocatalysts for energy conversion reactions such as small organic molecule oxidation and hydrogen evolution, but are mainly limited to alloys of Pt with transition metals. Herein, a new PtGa electrocatalyst with unique nanoporous architecture and self-supported feature (np-PtGa)...

Designing highly efficient, earth abundant and robust electrocatalysts for oxygen evolution reaction (OER) plays a vital role during the development of various renewable energy storage and conversion devices, but still remains challenging. Using liquid metal as a mediator, herein we report a novel painting-alloying-dealloying strategy to synthesize...

Eutectic reaction frequently occurs in metallurgical solidification of alloy melts, and has been widely studied for traditional structural and engineering applications for decades. Here, we inject new blood into this ancient process and develop its novel application in the general preparation of advanced nanostructured materials. Based upon solidif...

Magnesium-ion batteries (MIBs) have recently received great concerns, but are restrained by the challenge of exploring advanced anode materials with superior capacity and fast diffusion kinetics. Herein, for the first time we proposed a dual phase alloying strategy to address this issue, and developed novel high-performance bismuth (Bi)-tin (Sn) al...

Materials scientists always dream to ‘paint’ nanostructured metal on a metallic foil, just as artists paint a painting on a canvas. Herein we for the first time realize this dream using liquid gallium (Ga) as the paint. Through a liquid Ga stimulated painting-alloying-dealloying strategy, kinds of nanostructured metallic films including Au, Ag, Pd,...

Metal-based anodes have recently aroused much attention in sodium ion batteries (SIBs) owing to their high theoretical capacities and low sodiation potentials. However, their progresses are prevented by the inferior cycling performance caused by severe volumetric change and pulverization during the (de)sodiation process. To address this issue, here...

Understanding the sodium (Na) chemistry is crucial for development of high-performance sodium ion batteries (SIBs). Nanostructured bismuth (Bi) has shown great potentials as an anode in SIBs, however, the Na storage mechanisms of Bi are still unclear. Herein, the operando X-ray diffraction (XRD) technique was utilized to probe the Na storage mechan...

Developing advanced electrode materials and understanding the electrochemistry of electrode reactions are two main issues to be addressed for high-performance sodium ion batteries (SIBs). Through a one-step dealloying strategy which simultaneously incorporates the nanoarchitecture, mesoporous structure and nanocomposite of electrode materials, here...

Developing low cost, highly active, and stable bifunctional electrocatalysts for overall water splitting is significant for sustainable energy systems. Herein, we report the synthesis of three dimensional porous nickel diselenide nanowrinkles anchored on nickel foam through fabricating nickel oxalate nanosheets on nickel foam by immersion, followed...

One-dimensional (1D) nanostructures have been receiving wide concerns due to their unique properties and potential applications, however, their low-cost high-efficient synthesis remains a great challenge. Herein, we propose a eutectic-directed self-templating strategy to synthesize PtNi nanoporous nanowires (NPNWs) through the combination of rapid...

It is a great challenge to design highly active, stable and low-cost catalysts for electrochemically splitting water to realize the clean energy generation and renewable energy storage. Herein, a facile one-step dealloying strategy was proposed to synthesize mesoporous CoFe-based oxides and layered double hydroxides (LDHs). Benefitting from the fas...

Metallic actuators have recently aroused great interests, and alloying of noble element with earth-abundant metal is essential to lower the cost of actuation materials while keeping a significant strain response. Here, we report the design/fabrication of bulk nanoporous nickel-palladium alloy by dealloying. The alloy with a hierarchically porous st...

Development of excellent bi-functional electrocatalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remains a key issue for the commercialization of various electrochemical devices such as fuel cells and metal-air batteries. Herein, we report the synthesis and electrocatalytic performance of mesoporous nanostructure...

Owing to high theoretical specific capacitance of 3560 F g⁻¹ and intrinsic activity towards oxygen evolution reaction (OER), inexpensive Co3O4 is drawing much attention as either a promising pseudocapacitive electrode or OER catalyst. However, restricted to poor conductivity and lack of active sites, Co3O4 usually exhibits limited experimental capa...

At present, metal/metal oxide composites are considered as potential oxygen reduction reaction (ORR) catalysts for energy-related applications like fuel cells. Here, we fabricated a high-activity, low Pt loading ORR electrocatalyst comprised of nanoporous Pt (np-Pt) in intimate contact with lamellar (Mn,Al)3O4 nanosheet (NS). In comparison to Pt/C...

Pt-based electrocatalysts play a crucial role in both the anode and cathode reactions of direct methanol fuel cells (DMFCs), but their activity/durability and cost are still the main issues to be addressed. Through the combination of mechanical alloying with dealloying, here we have fabricated a nanoporous PtCuTi (np-PtCuTi) alloy with a low Pt con...

Microstructural and compositional evolution of nanoporous silver (NPS) during dealloying of rapidly solidified Mg65Ag35 alloy in the 1 wt% HCl solution has been investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray analysis. The amount of MgAg phase decreases and that of f.c...

This study reports a unique binder-free nickel oxalate (NiC2O4) nanodiamond-decorated Ni foam which is fabricated through anodization, as a new-type electrode material for nonenzymatic glucose biosensing. The electrode presents multilinear detection ranges with ultrahigh sensitivities (up to 144.26 mA mm −1 cm−2) and an ultralow detection limit (5...

Oxygen reduction reaction (ORR) is of crucial importance in fuel cells and metal−air batteries, however, the sluggish dynamics of ORR remains a critical issue to be addressed. Here, we report the preparation of hexagonal spinel-type Mn2AlO4 nanosheets with a high BET surface area of up to 164 m2 g−1 through a dealloying- annealing strategy. The Mn2...