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The conversion of solar‐thermal (ST) power into electrical power along with its efficient storage represents a crucial and effective approach to address the energy crisis. The thermoelectric (TE) generator can absorb ST power and transform it into electrical energy, making it a highly viable technology to achieve photo‐thermal conversion (PTC). However, the practical application of the pristine TE generator devices on a larger scale is still facing several challenges. On the one hand, the pristine TE generator device has low inherent PTC efficiency, thereby leading to low power conversion. On the other hand, such solar‐thermoelectric (STE) conversion does not provide the functionality of electric energy storage. Herein, an effective strategy has been proposed that employs a CoAl2O4 PTC coating to decorate the pristine TE generator for developing the STE generator device with the remarkable STE performance and then coupling this device with a supercapacitor (SC) for effective storage power. In comparison to the pristine TE generator, the developed STE device exhibited considerable enhancement in both the open‐circuit voltage (Voc) and its maximum power density, displaying more than a 4‐ and 15‐fold improvement, respectively. In addition, the feasibility of coupling this solar‐driven STE generator device in series with a SC for ST conversion and storage was verified, and the working mechanism has been elucidated. This work presents a promising approach to effectively convert and store clean solar power into electrical energy, enabling practical applications of STE generator devices in conjunction with other electrochemical energy storage devices. [ABSTRACT FROM AUTHOR]

Similar to lithium‐ion batteries (LIBs), during the first charge/discharge process of lithium‐ion capacitors (LICs), lithium‐intercalated anodes (e.g., silicon, graphite, and hard carbon) also exhibit irreversible lithium intercalation behaviors, such as the formation of a solid electrolyte interface (SEI), which will consume Li+ in the electrolyte and significantly reduce the electrochemical performance of the system. Therefore, pre‐lithiation is an indispensable procedure for LICs. At present, commercial LICs mostly use lithium metal as the lithium source to compensate for the irreversible capacity loss, which has the demerits of operational complexity and danger. However, the pre‐lithiation strategy based on cathode sacrificial lithium salts (CSLSs) has been proposed, which has the advantages of low cost, simple operation, environmental protection, and safety. Therefore, there is an urgent need for a timely and comprehensive summary of the application of CSLSs to LICs. In this review, the important roles of pre‐lithiation in LICs are detailed, and different pre‐lithiation methods are reviewed and compared systematically and comprehensively. After that, we systematically discuss the pre‐lithiation strategies based on CSLSs and mainly introduce the lithium extraction mechanism of CSLSs and the influence of intrinsic characteristics and doping amount of CSLSs on LICs performance. In addition, a summary and outlook are conducted, aiming to provide the essential basic knowledge and guidance for developing a new pre‐lithiation technology. [ABSTRACT FROM AUTHOR]

Developing high‐voltage and environmentally friendly aqueous electrolytes have become a significant trend in supercapacitors (SCs). However, achieving this goal usually requires the use of "water‐in‐salt" (WIS) electrolytes, inevitably increasing manufacturing costs and sometimes posing problems such as environmental pollution. Here, we developed a water/organic solvent hybrid electrolyte (8 m NaClO4‐20 % H2O‐30 % ACN‐50 % PEG‐200) with low cost and high‐voltage capacity using the water‐miscible polymer polyethylene glycol (PEG) as a crowding agent to suppress water activity, and acetonitrile (ACN) as a co‐solvent to improve the ion transport properties. The synergistic advantages of the two co‐solvents allow SCs using this electrolyte to have a high operative voltage window of up to 2.6 V, currently the highest operating voltage for aqueous carbon‐based SCs, excellent capacity retention (over 11000 cycles) and high energy densities (31.2 Wh kg−1). This work provides a promising method for developing green and inexpensive high‐voltage window aqueous electrolytes. [ABSTRACT FROM AUTHOR]

Perovskite materials can store charge through rapid oxygen anions intercalation. Although numerous perovskite materials owing to rich selections of A and B‐site elements are reported as electrodes of supercapatteries, the effect of the crystal structure of perovskite materials on their electrochemical performance has never been studied so far. Herein, using SrCo0.9Mo0.1O3−δ, SrFeO3−δ, Ba0.5Sr0.5Co0.8Fe0.2O3−δ, and LaMnO3−δ as research targets, it is proved that their corresponding cubic structure materials display the best electrochemical performance. And then, the origin of such superiority of cubic structure for SrCo0.9Mo0.1O3−δ is explored through experimental investigations and theoretical calculations. The results show that the increase in the content of oxygen vacancies and the enhancement of B‐O hybridization of cubic structure can optimize the electronic structure of the perovskite materials, thereby improving its conductivity and accelerating the reaction kinetics. The filtering strategy based on crystal structure proposed by this report will provide a new perspective to faster and more efficient choice of perovskite materials for supercapatteries. [ABSTRACT FROM AUTHOR]

Dual‐ion batteries (DIBs) have gained great attention due to their advantages of high operating voltage and low cost. However, the overall performance of the reported DIBs falls far below expectation. In particular, electrode materials with rapid‐charging kinetics and high volumetric packing densities are still in short supply. Herein, a holistic design of the DIB is proposed by using a Wadsley–Roth phase niobium tungsten oxide as the anode, which possesses facile ion transport tunnels and ultrahigh electrode density to deliver superior volumetric performance (521.5 Ah L−1 at 0.2 C and 154.3 Ah L−1 at 60 C), and choosing graphite as the cathode. Benefiting from the respective advantages of this novel anode and the graphite cathode, the as‐built DIB full cell exhibits high volumetric and excellent rate performance (137.7 Ah L−1 at 1 C and 79.2 Ah L−1 at 5 C), and long‐term cyclic stability (1000 cycles at 5 C with negligible capacity attenuation). More impressively, such cells can deliver a high volumetric energy density (422.7 Wh L−1) and power density (8.3 kW L−1). Furthermore, the comprehensive charge storage chemistry of this DIB is elaborated by operando electrochemical characterizations, and this assembly of flexible pouch cells shows its practical prospects. [ABSTRACT FROM AUTHOR]

In this study, sodium ion hybrid capacitors (SIHCs) constructed by using battery‐type carbon nanosheet (CNS) as anode and capacitive activated carbon (AC) as cathode are reported. The CNSs with large interlayer spacing were deposited on Na2CO3 powder by using chemical vapor deposition method. The CNS anode for sodium ion storage exhibits outstanding rate capability (138 mAh g−1 at 10 A g−1, 63 % retention of the capacity at 0.05 A g−1) and excellent long‐term cyclability at 10 A g−1 after 12500 cycles. Benifting from high performance of anodes abovemensioned, the assembled SIHC based on CNS and AC, operated in a voltage window of 1.0∼4.0 V, delivers a high specific energy of 135 Wh kg−1 at 250 W kg−1 and a maximum power of 25 kW kg−1 with the output 69 Wh kg−1. [ABSTRACT FROM AUTHOR]

Abstract: Sodium‐ion hybrid capacitors (SIHCs) can potentially combine the virtues of high‐energy density of batteries and high‐power output as well as long cycle life of capacitors in one device. The key point of constructing a high‐performance SIHC is to couple appropriate anode and cathode materials, which can well match in capacity and kinetics behavior simultaneously. In this work, a novel SIHC, coupling a titanium dioxide/carbon nanocomposite (TiO2/C) anode with a 3D nanoporous carbon cathode, which are both prepared from metal–organic frameworks (MOFs, MIL‐125 (Ti) and ZIF‐8, respectively), is designed and fabricated. The robust architecture and extrinsic pseudocapacitance of TiO2/C nanocomposite contribute to the excellent cyclic stability and rate capability in half‐cell. Hierarchical 3D nanoporous carbon displays superior capacity and rate performance. Benefiting from the merits of structures and performances of anode and cathode materials, the as‐built SIHC achieves a high energy density of 142.7 W h kg−1 and a high power output of 25 kW kg−1 within 1–4 V, as well as an outstanding life span of 10 000 cycles with over 90% of the capacity retention. The results make it competitive in high energy and power–required electricity storage applications. [ABSTRACT FROM AUTHOR]

Carbon based materials as one promising cathode to accommodate the insoluble and insulating discharge products (Li2O2) for lithium oxygen (Li-O2) batteries have attracted great attention due to their large energy density store ability compared with the other carbon-free cathodes. However, the side reaction occurring at carbon/Li2O2 interfaces hinders their large-scale application in Li-O2 batteries. Herein, a simple and cost-effective strategy is developed for the growth of core-shell-like Co/CoO nanoparticles on 3D graphene-wrapped carbon foam using 3D melamine foam as the initial backbone. This unique 3D hierarchical carbonized melamine foam-graphene-Co/CoO hybrid (CMF-G-Co/CoO) with a continuous conductive network and elastic properties is used as binder-free oxygen electrode for Li-O2 batteries. Electrochemical and structural measurements show that a synergistic effect is observed between Co/CoO and graphene, where Li2O2 grows on the Co/CoO surfaces instead of the carbon surfaces at the initial discharge state (500 mAh ), indicating the reduced carbon/Li2O2 interfaces and alleviative side reactions during the electrochemical process. Importantly, the CMF-G-Co/CoO electrode can achieve greatly improved cycle life over the electrode without aid of the Co/CoO. Furthermore, it delivers a large capacity of ≈7800 mAh and outstanding rate capability, exhibiting the great potential for the application in Li-O2 batteries. [ABSTRACT FROM AUTHOR]

Lithium-oxygen (Li-O2) batteries are receiving intense interest because of their high energy density. A new tubular δ-MnO2 material prepared by a simple hydrothermal synthesis is an efficient electrocatalyst for Li-O2 batteries. The synthesized δ-MnO2 exhibits a unique tubular structure, in which the porous walls are composed of highly dispersed ultrathin δ-MnO2 nanosheets. Such a unique structure and its intrinsic catalytic activity provide the right electrocatalyst characteristics for high-performance Li-O2 batteries. As a consequence, suppressed overpotentials-especially the oxygen evolution reaction overpotential-superior rate capability, and desirable cycle life are achieved with these submicron δ-MnO2 tubes as the electrocatalyst. Remarkably, the discharge product Li2O2 of the Li-O2 battery exhibits a uniform nanosheet-like morphology, which indicates the critical role of the δ-MnO2 in the electrochemical process, and a mechanism is proposed to analyze the catalysis of δ-MnO2. [ABSTRACT FROM AUTHOR]

Li-ion hybrid capacitors (LIHCs), consisting of an energy-type redox anode and a power-type double-layer cathode, are attracting significant attention due to the good combination with the advantages of conventional Li-ion batteries and supercapacitors. However, most anodes are battery-like materials with the sluggish kinetics of Li-ion storage, which seriously restrict the energy storage of LIHCs at the high charge/discharge rates. Herein, vanadium nitride (VN) nanowire is demonstated to have obvious pseudocapacitive characteristic of Li-ion storage and can get further gains in energy storage through a 3D porous architecture with the assistance of conductive reduced graphene oxide (RGO). The as-prepared 3D VN-RGO composite exhibits the large Li-ion storage capacity and fast charge/discharge rate within a wide working widow from 0.01-3 V (vs Li/Li+), which could potentially boost the operating potential and the energy and power densities of LIHCs. By employing such 3D VN-RGO composite and porous carbon nanorods with a high surface area of 3343 m2 g−1 as the anode and cathode, respectively, a novel LIHCs is fabricated with an ultrahigh energy density of 162 Wh kg−1 at 200 W kg−1, which also remains 64 Wh kg−1 even at a high power density of 10 kW kg−1. [ABSTRACT FROM AUTHOR]

Owing to their unique nanosize effect and surface effect, pseudocapacitive quantum dots (QDs) hold considerable potential for high‐efficiency supercapacitors (SCs). However, their pseudocapacitive behavior is exploited in aqueous electrolytes with narrow potential windows, thereby leading to a low energy density of the SCs. Here, a film electrode based on dual‐confined FeOOH QDs (FQDs) with superior pseudocapacitive behavior in a high‐voltage ionic liquid (IL) electrolyte is put forward. In such a film electrode, FQDs are steadily dual‐confined in a 2D heterogeneous nanospace supported by graphite carbon nitride (g‐C3N4) and Ti‐MXene (Ti3C2). Probing of potential‐driven ion accumulation elucidates that strong adsorption occurs between the IL cation and the electrode surface with abundant active sites, providing sufficient redox reaction of FQDs in the film electrode. Furthermore, porous g‐C3N4 and conductive Ti3C2 act as ion‐accessible channels and charge‐transfer pathways, respectively, endowing the FQDs‐based film electrode with favorable electrochemical kinetics in the IL electrolyte. A high‐voltage flexible SC (FSC) based on an ionogel electrolyte is fabricated, exhibiting a high energy density (77.12 mWh cm−3), a high power density, a remarkable rate capability, and long‐term durability. Such an FSC can also be charged by harvesting sustainable energy and can effectively power various wearable and portable electronics. [ABSTRACT FROM AUTHOR]

The solar‐thermal conversion of sunlight into heat has received considerable attention due to its low cost and high conversion efficiency. Microsupercapacitors (MSCs) are a promising class of microscale power sources for microelectronic devices, but low‐temperature operation is a huge challenge for their potential applications due to sluggish diffusion kinetics. Here, a simple strategy of adhering a graphene photothermal film on the backside of a model MSC to realize the device self‐heating at low temperatures is demonstrated. At an extremely low ambient temperature of −50 °C, graphene film can increase the actual operating temperature of MSC to −16.5 °C under irradiation of 1 sun. Solar‐driven self‐heating resulted in a 4.5‐fold increase in the specific capacitance, a 2.7‐fold increase in the rate capability, and a 2.8‐fold increase in the energy density without compromising the cyclic stability. This work presents a new application for solar energy and a new approach to improve the overall performance of MSCs at low temperatures. Combining the photothermal effect of graphene with a microsupercapacitor to boost its performance at low temperatures is proposed. A graphene film as a photothermal film, which is attached on the backside of a model microsupercapacitor, can convert sunlight into thermal energy to increase the internal temperature of the microsupercapacitor, thereby accelerating ion mobility in electrolytes and ultimately enhancing the electrochemical performance of the device. [ABSTRACT FROM AUTHOR]