In this work, a SnO /ZnO bilayered electron transporting layer (ETL) aimed to achieve low energy loss and large open-circuit voltage (V ) for high-efficiency all-inorganic CsPbI Br perovskite solar cells (PVSCs) is introduced. The high-quality CsPbI Br film with regular crystal grains and full coverage can be realized on the SnO /ZnO surface. The higher-lying conduction band minimum of ZnO facilitates desirable cascade energy level alignment between the perovskite and SnO /ZnO bilayered ETL with superior electron extraction capability, resulting in a suppressed interfacial trap-assisted recombination with lower charge recombination rate and greater charge extraction efficiency. The as-optimized all-inorganic PVSC delivers a high V of 1.23 V and power conversion efficiency (PCE) of 14.6%, which is one of the best efficiencies reported for the Cs-based all-inorganic PVSCs to date. More importantly, decent thermal stability with only 20% PCE loss is demonstrated for the SnO /ZnO-based CsPbI Br PVSCs after being heated at 85 °C for 300 h. These findings provide important interface design insights that will be crucial to further improve the efficiency of all-inorganic PVSCs in the future.

Hydronium-ion batteries are regarded as one of the most promising energy technologies as next-generation power sources, benefiting from their cost effectivity and sustainability merits. Herein, we propose a hydronium-ion battery which is based on an organic pyrene-4,5,9,10-tetraone anode and an inorganic MnO2@graphite felt cathode in an acid electrolyte. Its operation involves a quinone/hydroquinone redox reaction on anode and a MnO2/Mn2+ conversion reaction on cathode, in parallel with the transfer of H3O+ between two electrodes. The distinct operation mechanism affords this hydronium-ion battery an energy density up to 132.6 Wh kg−1 and a supercapacitor-comparable power density of 30.8 kW kg−1, along with a long-term cycling life over 5000 cycles. Furthermore, surprisingly, this hydronium-ion battery works well even with a frozen electrolyte under −40 °C, and superior rate performance and cycle stability remain at −70 °C.

Most rechargeable batteries suffer from severe capacity loss at low temperature, which limits their applications in cold environments. Herein, we propose an original proton battery, which involves a MnO2@graphite felt cathode and a MoO3 anode in an acid electrolyte containing Mn2+. Its operation depends on the MnO2/Mn2+ conversion in the cathode and H3O+ insertion/extraction in the anode. This battery exhibits a promising energy density (177.4 Wh kg–1) and a supercapacitor-like power density (66.6 kW kg–1) at room temperature. We demonstrate that the electrolyte shows high conductivities even after freezing at low temperatures. As a result, a solid-state proton battery is formed at −70 °C, which maintains 81.5% of the room temperature capacity and shows an unprecedented cycle stability (a negligible capacity fading over 100 cycles). Furthermore, even at −78 °C, it can still deliver sufficient energy to power an electric device.