energy densities (100-160 Wh kg −1), they suffer from both slow charging rates attributed to their low power densities (<1000 W kg −1) and also short cycle stability. [3,4] As alternative energy storage systems (ESS), electrochemical capacitors (ECs) allow higher power densities and better cycle stability than LIBs, but typical ECs allow extremely small energy densities due to the surface-limited charge-discharge redox reactions. [5] Hence, the sole usage of a LIB or an EC does not give simultaneously high energy and power densities along with long cycle stability because of their complementary ion storage mechanisms. As a solution to this challenge, hybrid energy storages (HESs), where charges are asymmetrically stored by battery-type reactions in the anode and pseudocapacitive reactions in the cathode, are of great attraction as their charge and discharge processes can be controlled using different potential windows to increase energy density. [6-9] However, despite this promise, an anode structure is having both rich active sites for high capacity and also fast cation transport channels and electron conduction pathways, [10-13] and its compatible cathode structure is allowing both rapid anion movement and facile electron conduction and also rich ion adsorption and pseudocapacitive reactions are vital to realizing high energy density for prolonged operation in a single charge and high power density for fast chargeable capability in the HES full cell device. [14-16] In this work, we synthesize the mesoporous molybdenum dioxide structures derived from metal-organic frameworks (MOFs) coated with reduced graphene oxide (rGO) shells as high-capacity and high-rate anode structures (MoO 2 @rGO) and the in situ polymerized crosslinked polyaniline (PANI) chain-integrated rGO structures as high-capacity and high-rate cathode structures (PANI@rGO). MoO 2 has a high theoretical capacity (838 mAh g −1), efficient charge stability with the low electrical resistivity (≈8.8 × 10 −5 Ω cm −1 at 300 K), and excellent chemical stability. [17] However, to utilize MoO 2 as an anode material unit for high-capacity, its poor diffusivity and conductivity Hybrid lithium-ion energy storage devices are promising for future applications, but their anodes and cathodes still have structural limitations, for example, accommodating rich cationic/anionic reactions, rapid charge movement, and long cycle life. Herein, high-capacity/high-rate anode and cathode structures are developed to overcome these challenges. Molybdenum oxide (MoO 2)-implanted carbon frameworks making conductive carbon bonds with reduced graphene oxide (rGO) shells are developed as anode structures by forming mesoporous channels for fast lithium-ion transport, carbon-rGO pathways for facile electron conduction, and ultrafine MoO 2 units for high capacity. The operando X-ray diffraction and kinetics analyses reveal that lithium-ion insertion and extraction occur via capacitive and diffusioncontrolled reactions. Also, polyaniline (PANI) chains are elongated on rGO sheets throug...

Perovskite halides are of great attraction as efficient light absorption materials for solid-state solar cells, but the stability and photovoltaic energy conversion efficiency of perovskite solar cells (PSCs) are still limited by the interface structures and defects between their light-absorbing perovskite halides and electron transport layers (ETLs). Here, we report the ultraviolet (UV) light-induced degradation mechanism at the interfaces between perovskite halide and conventional TiO2 ETL materials and provide a solution to overcome this drawback. UV-induced degradation is shown to be attributed to the formation of oxygen vacancies formed at the perovskite halide–ETL interface under UV light illumination, where the oxygen atoms released at the interface accelerate the decomposition of perovskite halide by inducing chemical reactions. Meanwhile, nanocrystalline SrTiO3 (STO) ETLs are revealed to be tunable in enabling high performance in PSCs under UV light illumination. Indeed, tuning the electronic structure of STO ETLs by Nb doping, in combination with the controllable removal of SrO phases segregated on the Nb-doped STO ETL surfaces, is exhibited to enable robust interface stability and stable high photovoltaic energy conversion efficiency for PSCs. Furthermore, we demonstrate that STO-based PSCs have no hysteresis due to low defect concentrations at the perovskite halide–STO ETL interfaces.

Perovskite solar cells (PSCs) have great potential as an efficient solar energy harvesting system due to their outstanding optoelectronic properties, but the charge accumulation and recombination, as well as the moisture-induced degradation of the light-absorbing perovskite layers, remain great bottlenecks in practical applications for future technology. As a solution to this challenge, here we report a strategy to realize moisture-stable PSCs allowing fast charge transfer that, in turn, leads to high power conversion efficiency (PCE). Hybridization of hygroscopic copper­(II) benzene-1,3,5-tricarboxylate metal–organic frameworks (Cu-BTC MOFs) with a light-absorbing perovskite layer for PSCs, where a moderate level of moisture attracted by Cu-BTC MOFs during the synthesis step, leads to enhanced perovskite crystallization. Besides, the perovskite–MOF hybrid facilitates the transfer of photoexcited electrons from the perovskite to TiO2 by providing additional channels for electron extraction. This enables a high PCE of 20.5% in a triple-cation perovskite–MOF device with negligible hysteresis compared to reference devices. Moreover, the perovskite–MOF hybrid exhibits high stability in ambient air under dark conditions over a long period (up to 22 months), while the unmodified counterpart quickly decomposes into PbI2. Consequently, this work provides a promising clue to realizeing fast charge transfer and high stability for high-performance PSCs.