• Energy Research
• 2016-2025close

A mixed conductive garnet/Li interface consisting of electronic conductive nanoparticles embedded in an ionic conductive network is constructed for dendrite-free solid garnet batteries.

A critical challenge for the commercialization of layer-structured nickel-rich lithium transition metal oxide cathodes for battery applications is their capacity and voltage fading, which originate from the disintegration and lattice phase transition of the cathode particles. The general approach of cathode particle surface modification could partially alleviate the degradation associated with surface processes, but it still fails to resolve this critical barrier. Here, we report that infusing the grain boundaries of cathode secondary particles with a solid electrolyte dramatically enhances the capacity retention and voltage stability of the cathode. We find that the solid electrolyte infused in the boundaries not only acts as a fast channel for lithium-ion transport, it also, more importantly, prevents penetration of the liquid electrolyte into the boundaries, and consequently eliminates the detrimental factors, which include cathode–liquid electrolyte interfacial reactions, intergranular cracking and layered-to-spinel phase transformation. This grain-boundary engineering approach provides design ideas for advanced cathodes for batteries. The development of Ni-rich layered lithium transition metal oxides is plagued by their voltage and capacity fading on battery cycling. Here, the authors demonstrate an effective approach to treat these problems by infusing a solid electrolyte into the grain boundaries of the secondary particles of these layered materials.

AbstractOwing to the rapidly increasing consumption of fossil fuels, finding clean and reliable new energy sources is of the utmost importance. Thus, developing highly efficient and low‐cost catalysts for electrochemical reactions in energy conversion devices is crucial. Single‐atom catalysts (SACs) with maximum metal atom utilization efficiency and superior catalytic performance have attracted significant attention, especially for electrochemical reactions. However, because of the highly unsaturated coordination environment, the stability of SACs can be a challenge for practical applications. In this review, we will summarize the strategies to increase the stability of SACs and synthesizing stable SACs, as well as the application of SACs in electrochemical reactions. Finally, we offer a perspective on the development of advanced SACs through rational design and a deeper understanding of SACs with the help of in situ or operando techniques in electrochemical reactions.

Achieving a balance between lithium ion and vacant site contents plays a crucial role in obtaining optimal ionic conductivity in halide electrolytes, especially with a hexagonal close packing (hcp) anion framework.

AbstractA fuel cell is an energy conversion device that can continuously input fuel and oxidant into the device through an electrochemical reaction to release electrical energy. Although noble metals show good activity in fuel cell‐related electrochemical reactions, their ever‐increasing price considerably hinders their industrial application. Improvement of atom utilization efficiency is considered one of the most effective strategies to improve the mass activity of catalysts, and this allows for the use of fewer catalysts, saving greatly on the cost. Thus, single‐atom catalysts (SACs) with an atom utilization efficiency of 100% have been widely developed, which show remarkable performance in fuel cells. In this review, we will describe recent progress on the development of SACs for membrane electrode assembly of fuel cell applications. First, we will introduce several effective routes for the synthesis of SACs. The reaction mechanism of the involved reactions will also be introduced as it is highly determinant of the final activity. Then, we will systematically summarize the application of Pt group metal (PGM) and nonprecious group metal (non‐PGM) catalysts in membrane electrode assembly of fuel cells. This review will offer numerous experiences for developing potential industrialized fuel cell catalysts in the future.

AbstractPt‐Ir catalysts have been widely applied in unitized regenerative fuel cells due to their great activity for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). However, the application of noble metals is seriously hindered by their high cost and low abundance. To reduce the noble metals loading and catalyst cost, the atomic layer deposition is applied to selectively surface anchoring of Ir single atoms (SA) on Pt nanoparticles (NP). With the formation of SA‐NP composite structure, the IrSA‐PtNP catalyst exhibits significantly improved performance, achieving 2.0‐ and 90‐times mass activity by comparison with the benchmark Pt/C catalyst for the ORR and OER, respectively. Density functional theory calculations indicate that the SA‐NP cooperation synergy endows the IrSA‐PtNP catalyst to surpass the bifunctional catalytic activity limit of Pt‐Ir NPs. This work provides a novel strategy for the construction of high‐performing dual catalyst through designing the single atom anchoring on NPs.image

Abstract The Sn-based materials have been hindered from practical use for lithium ion batteries due to the inherent volume change leading to poor cycling performance. To mitigate this challenge, in this study, amorphous SnO 2 /graphene aerogel nanocomposites are fabricated via a simple hydrothermal approach. The amorphous nature of SnO 2 is clearly determined in detail by transmission electron microscopy, aberration-corrected scanning transmission electron microscopy, and X-ray diffraction measurement. The as-prepared material shows satisfying reversible capacity and significant cyclic stability. For instance, it delivers an excellent discharge capacity of 700.1 mA h g −1 in 80th cycle at a current density of 100 mA g −1 , in accordance with a high retention capacity of 97.6% compared to that of the sixth cycles, which is much better than crystalline SnO 2 /graphene aerogel. The enhanced electrochemical performance can be ascribed to the intrinsic isotropic nature, smaller size, and high electrochemical reaction kinetics of amorphous SnO 2 , together with the graphene aerogels matrix. Therefore, this study may provide an effortless, economic, and environmental friendly strategy to fabricate high volume change electrode materials for lithium ion batteries.

AbstractElectrochemical supercapacitors with high energy density are promising devices due to their simple construction and long‐term cycling performance. The development of a supercapacitor based on electrical double‐layer charge storage with high energy density that can preserve its cyclability at higher power presents an ongoing challenge. Herein, we provide insights to achieve a high energy density at high power with an ultrahigh stability in an electrical double‐layer capacitor (EDLC) system by using carbon from a biomass precursor (cinnamon sticks) in a sodium ion‐based organic electrolyte. Herein, we investigated the dependence of EDLC performance on structural, textural, and functional properties of porous carbon engineered by using various activation agents. The results demonstrate that the performance of EDLCs is not only dependent on their textural properties but also on their structural features and surface functionalities, as is evident from the electrochemical studies. The electrochemical results are highly promising and revealed that the porous carbon with poor textural properties has great potential to deliver high capacitance and outstanding stability over 300 000 cycles compared with porous carbon with good textural properties. A very low capacitance degradation of around 0.066 % per 1000 cycles, along with high energy density (≈71 Wh kg−1) and high power density, have been achieved. These results offer a new platform for the application of low‐surface‐area biomass‐derived carbons in the design of highly stable high‐energy supercapacitors.

This review presents recent developments in the design and synthesis of Pt-based catalysts with high atom utilization efficiency and their enhanced catalytic performance in electrochemical catalytic reactions.