Electrochemical energy storage (EES) plays an important role in personal electronics, electrified vehicles, and smart grid. Lithium-ion batteries (LIBs) and supercapacitors (SCs) are two of the most important EES devices that have been widely used in our daily life. The energy density of LIBs is heavily dependent on the electrode capacity, in which the charge storage proceeds mainly in three different mechanisms, that is, alloying, conversion, and intercalation. Conventional LIBs show high energy density, but the rate performance is usually unfavorable. As a comparison, the SCs, which store energy based on electrochemical double layer capacitance (EDLC) or surface Faradaic redox pseudocapacitance, shows outstanding rate performance, but the energy density is still much worse than LIBs. Recently, intercalation pseudocapacitance appears as a new type of EES mechanism which stores energy into the bulk of electrode through a battery-like intercalation process but behaves similar to an electrode of SCs (fast reaction kinetics). Such intercalation pseudocapacitance can effectively narrow the gap between SCs and LIBs in energy density and power density, providing a new opportunity for the development of advanced energy storage system with both high energy density and power density. Up to now, more and more reports about intercalation pseudocapacitive materials have been appeared in literature, however, a systematic analysis of the recent development in intercalation pseudocapacitance is still lack. In this article, we provided an in-time review of the recent progress in the understanding of intercalation pseudocapacitive process and the development of related electrode materials for EES. Importance was paid to the difference between Faradaic surface-redox pseudocapacitance and intercalation pseudocapacitance, as well between battery-like intercalation and pseudocapacitive intercalation. Both cation interaction (Li+ and Na+) and oxygen anion intercalation pseudocapacitance was summarized.

Intercalation pseudocapacitance in electrochemical energy storage: recent advances in fundamental understanding and materials development

Recent advances in perovskite oxides as electrode materials for supercapacitors

Electrochemical capacitors charge and discharge more rapidly than batteries over longer cycles, but their practical applications remain limited due to their significantly lower energy densities. Pseudocapacitors and hybrid capacitors have been developed to extend Ragone plots to higher energy density values, but they are also limited by the insufficient breadth of options for electrode materials, which require materials that store alkali metal cations such as Li+ and Na+. Herein, we report a comprehensive and systematic review of emerging anion storage materials for performance- and functionality-oriented applications in electrochemical and battery-capacitor hybrid devices. The operating principles and types of dual-ion and whole-anion storage in electrochemical and hybrid capacitors are addressed along with the classification, thermodynamic and kinetic aspects, and associated interfaces of anion storage materials in various aqueous and non-aqueous electrolytes. The charge storage mechanism, structure-property correlation, and electrochemical features of anion storage materials are comprehensively discussed. The recent progress in emerging anion storage materials is also discussed, focusing on high-performance applications, such as dual-ion- and whole-anion-storing electrochemical capacitors in a symmetric or hybrid manner, and functional applications including micro- and flexible capacitors, desalination, and salinity cells. Finally, we present our perspective on the current impediments and future directions in this field.

Emerging trends in anion storage materials for the capacitive and hybrid energy storage and beyond.

Ultrasound-enhanced electrokinetic remediation for removal of Zn, Pb, Cu and Cd in municipal solid waste incineration fly ashes.

Efficient symmetrical electrodes of PrBaFe2-xCoxO5+δ (x=0, 0.2,0.4) for solid oxide fuel cells and solid oxide electrolysis cells

A-site cation-ordered double perovskite PrBaCo2O5+δ oxide as an anion-inserted pseudocapacitor electrode with outstanding stability

The effect of quantity and classifications of the hydration products, strength and alkalinity of the cement-municipal solid wastes incineration (MSWI) fly ash solidified body on the leaching concentration of Pb and Cd was investigated. The results revealed that the alkalinity of the solidified body is the key factor for the stabilisation/solidification of heavy metals Pb and Cd by cement. Taken the stabilisation/solidification of Pb and Cd ions into consideration, the optimised pH value of leachate shall be 9·5–10·5. The quantity and classifications of hydration products also play a role in the stabilisation/solidification of Pb and Cd by cement and the effect of calcium monosulphate aluminate hydrate (3CaO·Al2O3·CaSO4·12H2O, abbreviated as AFm), C3S2H3, C5S6H5 is better than that of ettringite (3CaO·Al2O3·3CaSO4·32H2O, abbreviated as AFt), C3S2H8, C-S-H in terms of stabilisation/solidification. As for the stabilisation/solidification mechanism, the metathetical precipitation effect, which is domi...

Effect of cement-MSWI fly ash hydration on the stabilisation/solidification of Pb and Cd

Ni-doped perovskite PrBaCo2O5+δ as supercapacitor electrode with enhanced electrochemical performance

The invention discloses a grading method for echelon utilization of waste solid oxide fuel cells. The method comprises the following steps of: performing appearance detection and X-ray detection on the collected waste solid oxide fuel cells, and performing voltage-current density test on the cells which are qualified in detection to obtain a voltage-current density curve; obtaining an open-circuitvoltage value and the maximum power density value of the current solid oxide fuel cell according to the voltage-current density curve; and comparing the open circuit voltage value and the maximum power density value with an open circuit voltage and the maximum power density preset for evaluation, and grading and recovering the solid oxide fuel cells. The grading method for the echelon utilizationof the waste solid oxide fuel cells can reasonably performs echelon utilization on the waste solid oxide fuel cells, and the waste cells are applied to different occasions according to the grading, so that the residual value of the cells is fully exerted, and the waste of energy is relieved as much as possible.

Yuqian Chen

Papers

A-site cation-ordered double perovskite PrBaCo2O5+δ oxide as an anion-inserted pseudocapacitor electrode with outstanding stability

Effect of cement-MSWI fly ash hydration on the stabilisation/solidification of Pb and Cd

Ni-doped perovskite PrBaCo2O5+δ as supercapacitor electrode with enhanced electrochemical performance

Grading method for echelon utilization of waste solid oxide fuel cells