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In the recycling process of spent lithium-ion batteries, the presence of a certain amount of aluminum ions not only increases the alkali consumption for iron and aluminum removal but also affects the purity of nickel, cobalt, manganese salts, and iron phosphate, thereby hindering the preparation of battery-grade products. Herein, the precipitation process of aluminum hydroxide from supersaturated sodium aluminate solution was investigated across varying temperatures with the addition of minimal quantity of active seeds. X-ray diffraction analysis identified gibbsite and bayerite crystallization in the active seed phases. Assessment of product particle size distribution using power spectral density indicated median particle sizes of 9.70, 18.89, 35.32, and 51.78 μm at temperatures of 45, 55, 65, and 75 °C, respectively, suggesting that elevated temperatures favored product particle size growth. Additionally, to elucidate the precipitation mechanism, the kinetic equation was augmented with the inclusion of instantaneous seed coefficient and specific surface area, yielding an apparent activation energy of 83.52 kJ/mol.

Lithium–sulfur (Li–S) batteries have high theoretical energy density and are regarded as a promising candidate for next-generation energy storage systems. However, their practical applications are hindered by the slow kinetics of sulfur conversion and polysulfide shuttling. In particular, large-scale pouch cells show much poor cyclability. Here, we develop a high-efficiency catalyst of V-doped CoSe2by studying the binary CoSe2–VSe2system and confirming its effectiveness in accelerating polysulfide conversion. The coin cell tests reveal an initial capacity of 1414 mAh g–1at 0.1 C and 1049 mAh g–1at 1 C and demonstrate 1000 times cyclability with a decaying rate of 0.05% per cycle. Furthermore, the assembly and construction of pouch cells were optimized with monolithic three-dimensional (3D) electrodes and a multistacking strategy. Specifically, a 3D metallic scaffold (3MS) was developed to host V-doped CoSe2nanowires and sulfur. In addition, Janus microspheres of C@TiO2were synthesized to capture polar polysulfides with their polar part of TiO2and adsorb nonpolar sulfur with their nonpolar part of carbon. By integrating with 3MS, C@TiO2microspheres can block all ion channels of 3MS and only allow Li ions in and out. These integral designs and monolithic structures enable multistacking pouch cells with high cyclability. A high-loading pouch cell was demonstrated with a total capacity of 700 mAh. The cell can be cycled for 70 times with a capacity retention of 65.7%. In brief, this work provides an integral strategy of catalyst design and overall 3D assembly for practical Li–S batteries in a large pouch cell format.

Metal–air batteries are a type of electrochemical cell that generates electrical energy by combining metal and oxygen from the air. They are a promising technology for energy storage and portable devices because of their high energy density, low cost, and environmental friendliness. However, the discharge products of these batteries are notoriously difficult to decompose, resulting in a high overpotential. Recent works have shown that semiconductors can capture solar energy and store it in batteries. When exposed to light, photocatalysts generate carriers (strong redox pairs), thereby increasing the electron migration rate and significantly reducing the overpotential of the metal–air battery reaction. Nevertheless, single photocatalysts often exhibit poor cycle performance due to serious carrier recombination. This review paper begins by briefly describing the fundamentals of photoelectrochemistry and then focuses on commonly used photocathode design principles and various reported photocatalysts. It also discusses the main challenges and issues caused by light, such as photocorrosion and electrolyte decomposition. Finally, the critical issues associated with photo electrodes, electrolytes, and electrode/electrolyte interfaces are emphasized, and perspectives on the development of high-performance light-assisted metal–air batteries are presented.

Despite good compatibility with Li metal, garnet solid electrolytes suffer from severe electron-attack-induced Li-metal penetration and large interfacial resistance. Here, a formic acid (HCOOH)-induced electron-blocking and lithiophilic interlayer is created via a spontaneous reaction with surface Li2CO3contamination on the garnet electrolyte (LLZTO) pellet. Unlike previous methods that involved immersing LLZTO in acidic solutions, this study employs a volatile small-molecule organic acid that is easily removable, condensed, and recyclable, thus circumventing the environmental drawbacks associated with acid waste. The Li symmetric cell assembled with HCOOH-treated LLZTO exhibits a low interfacial impedance (3 Ω cm2) and a high critical current density (1.7 mA cm–2) at room temperature, enabling the cell to cycle continuously for over 1000 h at 0.2 mA cm–2. Furthermore, under a stacking pressure of 2 MPa, stable lithium plating/stripping was achieved at a current density of 0.3 mA cm–2with the assistance of HCOOH treatment. Additionally, the battery paired with a LiFePO4cathode delivers a high capacity of 151.7 mAh g–1at 1 C and maintains 88.5% of the initial capacity after 500 cycles, suggesting the feasibility of this interfacial engineering strategy for garnet-based solid Li-metal batteries.

Given the escalating global energy scarcity, there is a pressing need for advanced energy supply solutions to accommodate the evolving transportation landscape. Consequently, there has been a surge in interest surrounding lithium metal batteries, particularly Li–air batteries (LABs), which researchers have showcased for their remarkable energy density, reaching up to 3500 Wh kg–1. However, despite decades of dedicated research efforts, LABs have not yet achieved practical commercialization as a result of challenges, such as external moisture infiltration and sluggish electrochemical kinetics within the battery. In this review, we elucidate the challenges linked with oxygen-permeable membranes (OPMs) in practical LABs, particularly when operating in open environments. Subsequently, we comprehensively evaluate all developed OPMs to date, aiming to enhance the performance of LABs, focusing on both outer- and inner-type OPMs. Finally, critical issues pertaining to oxygen selectivity, permeability, water resistance, and electrolyte compatibility are underscored, with perspectives offered on the development of high-performance OPMs.