Metal halide perovskite quantum dots, with high light-absorption coefficients and tunable electronic properties, have been widely studied as optoelectronic materials, but their applications in photocatalysis are hindered by their insufficient stability because of the oxidation and agglomeration under light, heat, and atmospheric conditions. To address this challenge, herein, we encapsulated CsPbBr 3 nanocrystals into a stable iron-based metal−organic framework (MOF) with mesoporous cages (∼5.5 and 4.2 nm) via a sequential deposition route to obtain a perovskite-MOF composite material, CsPbBr 3 @PCN-333(Fe), in which CsPbBr 3 nanocrystals were stabilized from aggregation or leaching by the confinement effect of MOF cages. The monodispersed CsPbBr 3 nanocrystals (4−5 nm) within the MOF lattice were directly observed by transmission electron microscopy and corresponding mapping analysis and further confirmed by powder X-ray diffraction, infrared spectroscopy, and N 2 adsorption characterizations. Density functional theory calculations further suggested a significant interfacial charge transfer from CsPbBr 3 quantum dots to , which is ideal for photocatalysis. The CsPbBr 3 @PCN-333(Fe) composite exhibited excellent and stable oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalytic activities in aprotic systems. Furthermore, CsPbBr 3 @PCN-333(Fe) composite worked as the synergistic photocathode in the photoassisted Li−O 2 battery, where CsPbBr 3 and PCN-333(Fe) acted as optical antennas and ORR/OER catalytic sites, respectively. The CsPbBr 3 @PCN-333(Fe) photocathode showed lower overpotential and better cycling stability compared to CsPbBr 3 nanocrystals or , highlighting the synergy between CsPbBr 3 and PCN-333(Fe) in the composite.

Li-O 2) batteries with high theoretical energy densities offer considerable potential for a new generation of energy storage technology. [1] In 1996, the first nonaqueous Li-O 2 battery was introduced with a polymer organic electrolyte and a carbon-cobalt composite cathode by Abraham and Jiang. [2] This was followed by the verification of the rechargeability of Li-O 2 batteries with manganese dioxide-super S cathodes for over 50 cycles by Bruce and co-workers, [3] after which nonaqueous Li-O 2 batteries received substantial research attention worldwide. A typical nonaqueous Li-O 2 battery includes a Li metal anode, an aprotic electrolyte and an O 2 cathode. It operates according to the reaction 2Li + O 2 ↔ Li 2 O 2 (2.96 V vs Li/Li +), in which O 2 is reduced to form Li 2 O 2 on the cathode during discharging and Li 2 O 2 is decomposed to O 2 and Li + through a reversible charging process. In this way, the battery delivers exceptional theoretical energy density of ≈3600 Wh kg −1. [4] This report is centered on nonaqueous Li-O 2 batteries, and the use of the term "Li-O 2 batteries" mentioned below represents "nonaqueous Li-O 2 batteries." To date, enormous progress has been achieved in the understanding and application of high-performance Li-O 2 batteries, however, their low practical discharge capacity, poor rate capability, low round-trip efficiency, and inferior cycling stability have greatly blocked their practical applications. The current major scientific and technical challenges of Li-O 2 batteries can be summarized as follows. 1) The slow kinetics of formation and decomposition of the discharge products lead to poor rate capability and low round-trip efficiency. 2) Cathode corrosion and electrolyte decomposition due to the attack by the discharge intermediates such as superoxide species, giving rise to poor cycling stability. 3) Pore clogging on the cathode arising from the stacking of insulated, insoluble discharge products blocks the mass transfer and oxygen/Li + diffusion, limiting the capacity and degrading the cycling performance. 4) The inevitable side reactions between the highly reactive Li anode and the organic electrolyte, crossover O 2 , CO 2 , etc., and the redox mediators (RMs), give rise to premature battery death. [1a,5] 5) The unavoidable Li dendrites caused by uncontrollable deposition of lithium, as well as the risk of collapse of the lithium anode due to the volume change during iterative plating/stripping processes, increase the probability of safety problems. [6] Consequently, the slow kinetics of Li 2 O 2 Porous materials possessing high surface area, large pore volume, tunable pore structure, superior tailorability, and dimensional effect have been widely applied as components of lithium-oxygen (Li-O 2) batteries. Herein, the theoretical foundation of the porous materials applied in Li-O 2 batteries is provided, based on the present understanding of the battery mechanism and the challenges and advantageous qualities of porous materials. Furthermore, recent progress in porous material...

Ap hotoinduced flexible Li-CO 2 battery with welldesigned, hierarchical porous,a nd free-standing In 2 S 3 @CNT/ SS (ICS) as abifunctional photoelectrode to accelerate both the CO 2 reduction and evolution reactions (CDRR and CDER) is presented. The photoinduced Li-CO 2 battery achieved ar ecord-high discharge voltage of 3.14 V, surpassing the thermodynamic limit of 2.80 V, and an ultra-low charge voltage of 3.20 V, achieving around trip efficiency of 98.1 %, which is the highest value ever reported (< 80 %) so far.T hese excellent properties can be ascribed to the hierarchical porous and freestanding structure of ICS,a sw ell as the key role of photogenerated electrons and holes during discharging and charging processes.Amechanism is proposed for pre-activating CO 2 by reducing In 3+ to In + under light illumination. The mechanism of the bifunctional light-assisted process provides insight into photoinduced Li-CO 2 batteries and contributes to resolving the major setbacks of the system.

during charging. [10][11] Furthermore, soluble redox mediators migrate to the anode for reduction by electron shuttle, leading to low efficiency and instability of Li metal anode. [12,13] Therefore, it is necessary to explore new ways to intrinsically promote the formation and decomposition of Li 2 O 2 and reduce the large overpotentials of Li-O 2 batteries.Recently, incorporating green and renewable solar energy to improve the reaction kinetics of ORR and OER in Li-O 2 batteries is recognized as one of the promising options. [14][15][16] Wu et al. first reported a photoassisted Li-O 2 battery with the dye-sensitized TiO 2 photoelectrode, which efficiently utilized the photovoltage to compensate for the battery's charging voltage. [17] Zhou et al. further employed a graphic carbon nitride as a cathode, achieving an ultralow charge potential (1.96 V). [18] With the introduction of illumination, the photogenerated electrons and holes on the cathode effectively enhance the kinetics of the OER process, leading to a reduced Li 2 O 2 oxidization overpotential. However, the rapid recombination rate of the photoelectrons and holes generated in semiconductors is still a key obstacle in photocatalyst-involving Li-O 2 batteries (Figure 1b). Conventionally, various state-of-art semiconductor heterojunctions, such as Schottky junctions, p-n junctions, and z-scheme heterostructures have been constructed to suppress the recombination of charge carriers. [19][20][21][22] Yet, the synthetic methods for heterostructures are complicated and rigorous. Accordingly, the noncontact and environmentally friendly external-magneticfield-tuned approach can be used as an efficient strategy. [23] It has been reported that the application of the magnetic field in the solar cell shows a significantly improved carrier separation and photoelectron conversion efficiency, which is ascribed to a deviation of the charge movement with a vertical force to the direction of movement in the magnetic field plane. [24] Hence, it is feasible and significant to apply an external magnetic field into a photoassisted Li-O 2 battery to enhance the ORR and OER kinetics of the battery.Based on the above understanding, we first report a novel prototype of a magnetic and optical field multi-assisted Li-O 2 battery with a 3D porous NiO nanosheets on the Ni foam (NiO/FNi) photoelectrode. Benefited from the abundant electron-hole pairs generated in the photoelectrode under the optical field, the difficult formation/decomposition of Li 2 O 2 during the discharge/charge process in a conventional Li-O 2The photoassisted lithium-oxygen (Li-O 2 ) system has emerged as an important direction for future development by effectively reducing the large overpotential in Li-O 2 batteries. However, the advancement is greatly hindered by the rapidly recombined photoexcited electrons and holes upon the discharging and charging processes. Herein, a breakthrough is made in overcoming these challenges by developing a new magnetic and optical field multi-assisted Li-O 2 battery with 3D por...

At present, photoassisted Li–air batteries are considered to be an effective approach to overcome the sluggish reaction kinetics of the Li–air batteries. And, the organic liquid electrolyte is generally adopted by the current conventional photoassisted Li–air batteries. However, the superior catalytic activity of photoassisted cathode would in turn fasten the degradation of the organic liquid electrolyte, leading to limited battery cycling life. Herein, we tame the above limitation of the traditional liquid electrolyte system for Li-CO2 batteries by constructing a photoassisted all-solid-state Li-CO2 battery with an integrated bilayer Au@TiO2/Li1.5Al0.5Ge1.5(PO4)3 (LAGP)/LAGP (ATLL) framework, which can essentially improve battery stability. Taking advantage of photoelectric and photothermal effects, the Au@TiO2/LAGP layer enables the acceleration of the slow kinetics of the carbon dioxide reduction reaction and evolution reaction processes. The LAGP layer could resolve the problem of liquid electrolyte decomposition under illumination. The integrated double-layer LAGP framework endows the direct transportation of heat and Li+ in the entire system. The photoassisted all-solid-state Li-CO2 battery achieves an ultralow polarization of 0.25 V with illumination, as well as a high round-trip efficiency of 92.4%. Even at an extremely low temperature of −73 °C, the battery can still deliver a small polarization of 0.6 V by converting solar energy into heat to achieve self-heating. This study is not limited to the Li–air batteries but can also be applied to other battery systems, constituting a significant step toward the practical application of all-solid-state photoassisted Li–air batteries.