Co3O4/Co nano-heterostructures embedded in N-doped carbon for lithium-O2 batteries

Construction of an Oxygen-Vacancy-Rich CeO2@CoO Heterojunction toward High-Performance Lithium-Oxygen Batteries

Lithium-oxygen (Li-O2) batteries theoretically possess an exceptional energy density comparable to gasoline (up to 3500 W h kg-1), but in practical applications, the discharge products are difficult to effectively decompose, which leads to clogging of the cathode, resulting in severe polarization, limited actual capacity, and shortened battery life for Li-O2 batteries. Herein, we construct a highly active and stable catalyst with d-f electronic orbit coupling as a redox center by anchoring CeO2 onto CoO, simultaneously, oxygen vacancy (Ov) and CeO2 coactivated CoO. By leveraging the effects of interface engineering and defect engineering on the electronic structure of the catalyst, the adsorption energy for LiO2 can be adjusted to an ideal range. This not only avoids surface passivation caused by excessively strong binding energy but also overcomes the issue of sluggish Li2O2 decomposition efficiency due to excessively weak binding energy. Bracingly, the CeO2/CoO-based Li-O2 batteries exhibit an ultralow charge-discharge polarization, and Li2O2 was successfully induced to nucleate uniformly in nanoflower-like shapes, which could promote the reversible decomposition of the discharge products during the charging process and thereby enhance the electrochemical performance of Li-O2 batteries. Therefore, the CeO2@CoO/CC cathode exhibited an ultralow overpotential of 0.57 V and achieved a high discharge capacity of 19,850 mA h g-1. This work provides an important reference for designing the structure of cathode catalysts for Li-O2 batteries and regulating the growth paths and morphologies of discharge products.

Prussian Blue Analogue-Templated Nanocomposites for Alkali-Ion Batteries: Progress and Perspective

Lithium-ion batteries (LIBs) have dominated the portable electronic and electrochemical energy markets since their commercialisation, whose high cost and lithium scarcity have prompted the development of other alkali-ion batteries (AIBs) including sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs). Owing to larger ion sizes of Na+ and K+ compared with Li+, nanocomposites with excellent crystallinity orientation and well-developed porosity show unprecedented potential for advanced lithium/sodium/potassium storage. With enticing open rigid framework structures, Prussian blue analogues (PBAs) remain promising self-sacrificial templates for the preparation of various nanocomposites, whose appeal originates from the well-retained porous structures and exceptional electrochemical activities after thermal decomposition. This review focuses on the recent progress of PBA-derived nanocomposites from their fabrication, lithium/sodium/potassium storage mechanism, and applications in AIBs (LIBs, SIBs, and PIBs). To distinguish various PBA derivatives, the working mechanism and applications of PBA-templated metal oxides, metal chalcogenides, metal phosphides, and other nanocomposites are systematically evaluated, facilitating the establishment of a structure-activity correlation for these materials. Based on the fruitful achievements of PBA-derived nanocomposites, perspectives for their future development are envisioned, aiming to narrow down the gap between laboratory study and industrial reality.

Integrated Design for Regulating the Interface of a Solid-State Lithium-Oxygen Battery with an Improved Electrochemical Performance

A composite solid-state electrolyte (SSE) with acceptable safety and durability is considered as a potential candidate for high-performance lithium-oxygen (Li-O₂) batteries. Herein, to address the safety issues and improve the electrochemical performance of Li-O₂ batteries, a solvent-free composite SSE is prepared based on the thermal initiation of poly(ethylene glycol) diacrylate radical polymerization, and an integrated battery is achieved by injecting an electrolyte precursor between electrodes during the assembly process through a simple heat treatment. The Li-metal symmetric cells based on this composite SSE achieve a critical current density of 0.8 mA cm^-2 and a stable cycle life of over 900 h at a current density of 0.2 mA cm^-2. This composite SSE effectively inhibits the erosion of O₂ on the Li metal anode, optimizes the interface between the electrolyte and cathode, and provides abundant reaction sites for the electrochemical reactions during cycling. The integrated solid-state Li-O₂ battery prepared in this work achieves stable long cycling (118 cycles) at a current density of 500 mA g^-1 at room temperature, showing the promising future application prospects.