Lithium Photo-intercalation of CdS-Sensitized WO3 Anode for Energy Storage and Photoelectrochromic Applications

Solar Energy Storage Using a Cu2 O-TiO2 Photocathode in a Lithium Battery

A Cu₂ O-TiO₂ photoelectrode is pr+oposed for simultaneous solar light energy harvesting and storing of electrochemical energy in an adapted lithium coin cell. The p-type Cu₂ O semiconductor layer is the light harvester component of the photoelectrode and the TiO₂ film performs as the capacitive layer. The rationale of the energy scheme shows that the photocharges generated in the Cu₂ O semiconductor induce lithiation/delithiation processes in the TiO₂ film as a function of the applied bias voltage and light power. A photorechargeable lithium button cell drilled on one side recharges with visible white light in ≈9 h in open circuit. It provides an energy density of ≈150 mAh g^-1 at 0.1 C discharge current in dark, and the overall efficiency is 0.29%. This work draws a new approach for the photoelectrode role to advance in monolithic rechargeable batteries.

Strategy of Voltage Match on the Maximum Power Point for a High-Efficiency Photorechargeable Device

A photorechargeable device can generate power from sunlight and store it in one device, which has a broad application prospect in the future. However, if the working state of the photovoltaic part in the photorechargeable device deviates from the maximum power point, its actual power conversion efficiency will reduce. The strategy of voltage match on the maximum power point is reported to achieve a high overall efficiency (η_oa) of the photorechargeable device assembled by a passivated emitter and rear cell (PERC) solar cell and Ni-based asymmetric capacitors. According to matching the voltage of the maximum power point of the photovoltaic part, the charging characteristics of the energy storage part are adjusted to realize a high actual power conversion efficiency of the photovoltaic part (η_pv). The η_pv of a Ni(OH)₂-rGO-based photorechargeable device is 21.53%, and the η_oa is up to 14.55%. This strategy can promote further practical application for the development of photorechargeable devices.

All-Solid-State Photo-Assisted Li-CO2 Battery Working at an Ultra-Wide Operation Temperature

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/Li_1.5Al_0.5Ge_1.5(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.

Three-dimensional BiVO4-based semiconductor photocathode for high efficiency photo-assisted Zn-iodine redox flow batteries

Aqueous Zn-iodine redox flow batteries have aroused great interest for the features of high capacity, excellent stability, low cost, and high safety, yet the dissatisfying energy efficiency still limits their future advancement. In this work, three-dimensional semiconductor BiVO₄nanoparticles decorated hierarchical TiO₂/SnO₂arrays (BiVO₄@TiO₂/SnO₂) were applied as photocathode in Zn-iodine redox flow batteries (ZIRFBs) for the realization of efficient photo-assisted charge/discharge process. The photogenerated carriers at the solid/liquid interfaces boosted the oxidation process of I^-, and thus contributed to a significant elevation in energy efficiency of 14.9% (@0.5 mA cm^-2). A volumetric discharge capacity was extended by 79.6% under light illumination, owing to a reduced polarization. The photocathode also exhibited an excellent durability, leading to a stable operation for over 80 h with a maintained high energy efficiency of ∼90% @0.2 mA cm^-2. The research offers a feasible approach for the realization of high-energy-efficiency aqueous Zn-iodine batteries towards high-efficiency energy conversion and utilization.

Advances in Electrochemical Energy Devices Constructed with Tungsten Oxide-Based Nanomaterials

Tungsten oxide-based materials have drawn huge attention for their versatile uses to construct various energy storage devices. Particularly, their electrochromic devices and optically-changing devices are intensively studied in terms of energy-saving. Furthermore, based on close connections in the forms of device structure and working mechanisms between these two main applications, bifunctional devices of tungsten oxide-based materials with energy storage and optical change came into our view, and when solar cells are integrated, multifunctional devices are accessible. In this article, we have reviewed the latest developments of tungsten oxide-based nanostructured materials in various kinds of applications, and our focus falls on their energy-related uses, especially supercapacitors, lithium ion batteries, electrochromic devices, and their bifunctional and multifunctional devices. Additionally, other applications such as photochromic devices, sensors, and photocatalysts of tungsten oxide-based materials have also been mentioned. We hope this article can shed light on the related applications of tungsten oxide-based materials and inspire new possibilities for further uses.

Integrated Photo-Responsive Batteries for Solar Energy Harnessing: Recent Advances, Challenges, and Opportunities

Photo-responsive batteries that enable the effective combination of solar harvesting and energy conversion/storage functionalities render a potential solution to achieve the large-scale utilization of unlimited and cost-effective solar energy and alleviate the limits of conventional energy storage devices. The internal integration of photo-responsive electrodes into rechargeable batteries with the simplest two-electrode configuration is regarded as a reliable and appealing strategy for highly-efficient and low-cost utilization of solar energy by simplifying the device architecture and improving the energy efficiency. This progress report provides a brief review on photo-responsive batteries with integrated two-electrode configuration that can achieve solar energy conversion/storage in one single device. The basic device architecture, operating principles and practical performance of various photo-responsive systems based on solar energy harvesting in various batteries including Li ion batteries, Li-S batteries, Li-I batteries, dual-liquid redox batteries, Li-O₂ batteries, non-Li anode-O₂ /air batteries are summarized and discussed. Finally, the future opportunities and challenges regarding the two-electrode photo-responsive batteries are proposed.

CdS nanoparticles grown in situ on oxygen deficiency-rich WO3−x nanosheets: direct Z-scheme heterojunction towards enhancing visible light-driven hydrogen evolution

This work introduces the synthesis of direct Z-scheme CdS/WO_3−x heterojunction photocatalysts and the application of photocatalytic hydrogen evolution.

Utilizing solar energy to improve the oxygen evolution reaction kinetics in zinc-air battery

Directly harvesting solar energy for battery charging represents an ultimate solution toward low-cost, green, efficient and sustainable electrochemical energy storage. Here, we design a sunlight promotion strategy into rechargeable zinc-air battery with significantly reduced charging potential below the theoretical cell voltage of zinc-air batteries. The sunlight-promoted zinc-air battery using BiVO₄ or α-Fe₂O₃ air photoelectrode achieves a record-low charge potential of ~1.20 and ~1.43 V, respectively, under illumination, which is lowered by ~0.5-0.8 V compared to the typical charge voltage of ~2 V in conventional zinc-air battery. The band structure and photoelectrochemical stability of photoelectrodes are found to be key factors determining the charging performance of sunlight-promoted zinc-air batteries. The introduction of photoelectrode as an air electrode opens a facile way for developing integrated single-unit zinc-air batteries that can efficiently use solar energy to overcome the high charging overpotential of conventional zinc-air batteries.