The adaptive regulation of solar and thermal radiation through windows plays a pivotal role in building energy conservation. However, most state-of-the-art electrochromic smart windows can only modulate solar radiation, achieving dynamic and compatible regulation of both solar and thermal radiation within a single integrated window remains highly desirable yet challenging. Herein, we present an all-season multiband electrochromic smart window that integrates dual-band electrochromism with dynamic radiative cooling through an electrode engineering desisn. The window not only controls the visible light and near-infrared independently, but also modulates the solar transmittance and mid-infrared thermal emittance dynamically and compatibly through bright heating, bright cooling and dark cooling states, thereby significantly reducing the building energy consumption. Furthermore, the window exhibits impressive electrochromic performance including high multiband optical contrast from visible to mid-infrared (ΔT_700nm=52.8%, Δε_8~14μm=0.53), fast switching speed (4.6/2.6 s for coloration/bleaching) and outstanding cycle stability (negligible degradation after 10,000 cycles). Notably, the window displays remarkable temperature control performance with 11.5°C lower than the low-emissivity glass. Simulations further confirm the higher energy-saving performance of the window than the low-emissivity glass in most climatic zones around the world. Our work provides a feasible strategy for designing all-season multiband electrochromic smart windows for energy-efficient buildings.

Aqueous electrolytes have the advantages of low cost, environmental friendliness, and fast ion transport kinetics, which show great low-temperature potential. However, the high freezing point limit practical applications. In electrolytes, the design of ion pairs can effectively improve the charge transport properties, while its effect on low-temperature performance is neglected. Here, we acquired the lithium trifluoromethanesulfonate (LiOTf)-based aqueous electrolytes with different ion pair structures. Using advanced characterization and simulation, it was revealed that the 10 m LiOTf electrolyte-enriched separated solvated ion pairs (SSIPs) show excellent ultralow-temperature stability. The changes in energy storage behavior under different temperature were discussed, which revealed that SSIPs contribute to efficient adsorption at low temperatures. The supercapacitor with 10 m LiOTf reached high energy density of 34.67 Wh/kg at −40 ℃ and maintained long cycle stability at −70 ℃. Our work suggests a strategy for the rational design of electrolytes that could enable next-generation ultralow-temperature electrochemical storage systems.

Despite the high energy density of lithium metal batteries (LMBs), their application in rechargeable batteries is still hampered due to insufficient safety. Here, we present a novel flame-retardant solid-state electrolyte based on polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) with nano SiO₂ aerogel as an inert filler but Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO) as an auxiliary component to enhance the ion conductivity. The introduction of SiO₂ aerogels imparts the polymer electrolyte with exceptional thermal stability and flame retardancy. Simultaneously, the interaction between hydroxyl groups of SiO₂ particles and PVDF-HFP creates a strong cross-linking structure, enhancing the mechanical strength and stability of the electrolyte. Furthermore, the presence of SiO₂ aerogel and LLZTO facilitates the dissociation of lithium salts through Lewis acid-base interactions, resulting in a high ionic conductivity of 1.01 × 10⁻³ S·cm⁻¹ and a wide electrochemical window of ~ 5.0 V at room temperature for the prepared electrolytes. Remarkably, the assembled Li|Li cell demonstrates the excellent resistance to lithium dendrite and runs stablly for over 1500 h at a current density of 0.25 mA·cm⁻². Thus, we prepare a pouch cell with high safety, which can work normally after short-circuiting under the external folding and cutting.

Metal-covalent organic frameworks (MCOF) as a bridge between covalent organic framework (COF) and metal organic framework (MOF) possess the characteristics of open metal sites, structure stability, crystallinity, tunability as well as porosity, but still in its infancy. In this work, a covalent organic framework DT-COF with a keto-enamine structure synthesized from the condensation of 3,3′-dihydroxybiphenyl diamine (DHBD) and triformylphloroglucinol (TFP) was coordinated with Cu²⁺ by a simple post-modification method to a obtain a copper-coordinated metal-covalent organic framework of Cu-DT COF. The isomerization from a keto-enamine structure of DT-COF to a enol-imine structure of Cu-DT COF is induced due to the coordination interaction of Cu²⁺. The structure change of Cu-DT COF induces the change of the electron distribution in the Cu-DT COF, which greatly promotes the activation and deep Li-storage behavior of the COF skeleton. As anode material for lithium-ion batteries (LIBs), Cu-DT COF exhibits greatly improved electrochemical performance, retaining the specific capacities of 760 mAh g⁻¹ after 200 cycles and 505 mAh g⁻¹ after 500 cycles at a current density of 0.5 A g⁻¹. The preliminary lithium storage mechanism studies indicate that Cu²⁺ is also involved in the lithium storage process. A possible mechanism for Cu-DT COF was proposed on the basis of FT-IR, XPS, EPR characterization and electrochemical analysis. This work enlightens a novel strategy to improve the energy storage performance of COF and promotes the application of COF and MCOF in LIBs.

Lithium metal batteries are emerging as a strong candidate in the future energy storage market due to its extremely high energy density. However, the uncontrollable lithium dendrites and volume change of lithium metal anodes severely hinder its application. In this work, the porous Cu skeleton modified with Cu₆Sn₅ layer is prepared via dealloying brass foil following a facile electroless process. The porous Cu skeleton with large specific surface area and high electronic conductivity effectively reduces the local current density. The Cu₆Sn₅ can react with lithium during the discharge process to form lithiophilic Li₇Sn₂ in situ to promote Li-ions transport and reduce the nucleation energy barrier of lithium to guide the uniform lithium deposition. Therefore, more than 300 cycles at 1 mA cm⁻² are achieved in the half-cell with an average Coulombic efficiency of 97.5%. The symmetric cell shows a superior cycle life of more than 1000 h at 1 mA cm⁻² with a small average hysteresis voltage of 16 mV. When coupled with LiFePO₄ cathode, the full cell also maintains excellent cycling and rate performance.

Lithium-metal batteries are regarded as the “Holy Grail” of next-generation batteries. However, lithium dendrite and anode volume expansion in cycles seriously hinders lithium-metal battery applications. Herein, we propose a precise and efficient strategy for stabilizing lithium-metal batteries via a lithiophilic Ag-modified Cu current host (Li@CuM/Ag). By applying the magnetron sputtering method, the lithiophilic silver layer can be anchored homogeneously on the Cu mesh. The lithiophilic silver layer effectively guides uniform Li deposition in the 3D host and realizes spatial control over Li nucleation. In addition, a dendrite-free lithium anode is successfully realized, which has been proven by in situ optical dynamic tests and Li deposition simulations. The symmetrical cell can maintain a low overpotential (230 mV) and long cycle life (90 h) at a large current of 10 mA cm⁻² for a plating amount of 3 mAh cm⁻². Furthermore, Li@CuM/AgLiCoO₂ cells exhibited a high-capacity retention rate (86.39%) after 150 cycles at 2 C. Lithiophilic hosts based on magnetron sputtering provide a feasible strategy for applications of lithium-metal batteries.

Rechargeable zinc-ion batteries with mild aqueous electrolytes are one of the most promising systems for large-scale energy storage as a result of their inherent safety, low cost, environmental-friendliness, and acceptable energy density. However, zinc metal anodes always suffer from unwanted dendrite growth, leading to low Coulombic efficiency and poor cycle stability and during the repeated plating/stripping processes, which substantially restrict their further development and application. To solve these critical issues, a lot of research works have been dedicated to overcoming the drawbacks associated with zinc metal anodes. In this overview, the working mechanisms and existing issues of the zinc metal anodes are first briefly outlined. Moreover, we look into the ongoing processes of the different strategies for achieving highly stable and dendrite-free zinc metal anodes, including crystal engineering, structural engineering, coating engineering, electrolyte engineering, and separator engineering. Finally, some challenges being faced and prospects in this field are provided, together with guiding significant research directions in the future.

Thermal energy is abundantly available in our daily life and industrial production, and especially, low-grade heat is often regarded as a byproduct. Collecting and utilizing this ignored energy by low-cost and simple technologies may become a smart countermeasure to relieve the energy crisis. Here, a unique device has been demonstrated to achieve high value-added conversion of low-grade heat by introducing redox-active organic alizarin (AZ) onto N-doped hollow carbon nanofibers (N–HCNF) surface. As-prepared N–HCNF/AZ can deliver a high specific capacitance of 514.3 F g⁻¹ (at 1 A g⁻¹) and an outstanding rate capability of 60.3% even at 50 A g⁻¹. Meanwhile, the assembled symmetric proton capacitor can deliver a high energy density of 28.0 Wh kg⁻¹ at 350.0 W kg⁻¹ and a maximum power density of 35.0 kW kg⁻¹ at 17.0 Wh kg⁻¹. Significantly, the thermally chargeable proton capacitors can attain a surprisingly high Seebeck coefficient of 15.3 mV K^–1 and a power factor of 6.02 µW g^–1. Taking advantage of such high performance, a satisfying open-circuit voltage of 481.0 mV with a temperature difference of 54 K is achieved. This research provides new insights into construction of high value-added energy systems requiring high electrochemical performances.

Flexible power devices play an increasingly crucial role in emerging flexible electronics. To improve the electrochemical performance of flexible power devices, novel electrode structures and new energy-storage systems should be designed. Herein, a novel flexible Li-ion hybrid capacitor (LIC) is designed based on an anode comprising Li₄Ti₅O₁₂ nanoplate arrays coated on carbon textile (LTO/CT) and a cathode comprising a flexible N-doped graphene/carbon-nanotube composite (NGC) film. The LTO/CT anode is fabricated by directly growing Li₄Ti₅O₁₂ nanoplates on CT with robust adhesion using a simple one-pot hydrothermal reaction. Considering the volume of a real-device flexible LIC, the NGC//LTO/CT configuration delivers high volumetric energy and power densities of 2 mWh·cm⁻³ and 185 mW·cm⁻³, respectively. Furthermore, the flexible LIC shows excellent flexibility and electrochemical stability, with extremely small capacity fluctuation under different bending states. This work demonstrates a scalable route to assemble flexible LICs as high-performance power devices.