• Energy Research

A simple and scalable interface-layer free monolithic perovskite/silicon tandem has been demonstrated achieving over 20% efficiency on a large area.

Illustration of protein-based MEG generating electricity by absorbing water from moisture.

Quasi-solid-state silver-zinc (Ag-Zn) batteries, featuring high energy density, stable voltage output, and outstanding safety, have been considered as promising power source for wearable electronics, while they suffer from poor areal capacity and insufficient rechargeability caused by low surface area and structural deterioration of cathode. In this work, we address these problems through redesigning the cathode with core-shell AgCl/carbon fiber structure decorated with MXene nanosheets. Benefiting from the unique structure with high surface area, the capacity is over two times higher than that with irregular morphology, and undesired Ag migration is suppressed owing to MXene protective layer, leading to enhanced structural integrity and ultralong cycle life. Theoretical calculations and experimental result reveal that a heterostructure is formed between MXene and Zn-coated AgCl, stabilizing the cathode structure. The battery demonstrates high capacity of 2.97 mAh cm−2 and impressive cyclability, maintaining 78% of initial capacity after 400 cycles at 4 mA cm−2, with nearly 100% coulombic efficiency. Moreover, robust mechanical flexibility is demonstrated in the separator-free batteries, and they can operate when twisted, cut, put on fire, and sealed in ice, suggesting the viability for practical application scenarios. This work offers pivotal guidance to construct stable electrodes and advanced batteries for powering electronics.

Abstract Thermochemical energy storage via metal oxide redox cycling is a potential cost-effective approach to store solar energy both chemically and thermally at high temperatures, enabling efficient solar thermal power production round-the-clock and on-demand. Perovskite manganites are a low-cost redox material that undergoes reversible reaction without side reactions up to 1000 °C and offers high storage capacities, which makes them promising energy storage materials in next-generation solar thermal power plants. In this study, the thermal properties of a typical perovskite manganite, CaMnO3, has been studied. CaMnO3 shows 893.2 kJ/kg energy storage capacity from 200 °C to 1000 °C, and 0.133 non-stoichiometry in N2. The material exhibits excellent stability with 150 redox cycles between 500 °C and 1000 °C. The thermodynamic efficiencies of two solar-driven combined cycle power systems with CaMnO3 based thermochemical energy storage system are also investigated. The steady-state mass and energy conservation equations are solved for all system components to calculate the thermodynamic properties and mass flow rates at all state points in the system. Preliminary results for a system with 120 MW nominal solar power input at a solar concentration ratio of 1000 are presented, designed for constant round-the-clock operation with 9 h of on-sun and 15 h of off-sun operation. The CaMnO3 particles store and release energy via the sensible heat and reaction heat, yield a net power block efficiency of approximately 60% and an overall energy conversion efficiency of up to 48.7%. Required storage tank sizes for the solids are estimated to be up to 2–3 smaller than those of state-of-the-art molten salt systems.