The abundant reserve and low cost of sodium have provoked tremendous evolution of Na-ion batteries (SIBs) in the past few years, but their performances are still limited by either the specific capacity or rate capability. Attempts to pursue high rate ability with maintained high capacity in a single electrode remains even more challenging. Here, an elaborate self-branched 2D SnS (B-SnS) nanoarray electrode is designed by a facile hot bath method for Na storage. This interesting electrode exhibits areal reversible capacity of ca. 3.7 mAh cm (900 mAh g) and rate capability of 1.6 mAh cm (400 mAh g) at 40 mA cm (10 A g). Improved extrinsic pseudocapacitive contribution is demonstrated as the origin of fast kinetics of an alloying-based SnS electrode. Sodiation dynamics analysis based on first-principles calculations, ex-situ HRTEM, in situ impedance, and in situ Raman technologies verify the S-edge effect on the fast Na migration and reversible and sensitive structure evolution during high-rate charge/discharge. The excellent alloying-based pseudocapacitance and unsaturated edge effect enabled by self-branched surface nanoengineering could be a promising strategy for promoting development of SIBs with both high capacity and high rate response.

Nanoscale surface engineering is playing important role in enhancing the performance of battery electrode. VO2 is one of high-capacity but less-stable materials and has been used mostly in the form of powders for Li-ion battery cathode with mediocre performance. In this work, we design a new type of binder-free cathode by bottom-up growth of biface VO2 arrays directly on a graphene network for both high-performance Li-ion and Na-ion battery cathodes. More importantly, graphene quantum dots (GQDs) are coated onto the VO2 surfaces as a highly efficient surface "sensitizer" and protection to further boost the electrochemical properties. The integrated electrodes deliver a Na storage capacity of 306 mAh/g at 100 mA/g, and a capacity of more than 110 mAh/g after 1500 cycles at 18 A/g. Our result on Na-ion battery may pave the way to next generation postlithium batteries.

Zinc-ion batteries are under current research focus because of their uniqueness in low cost and high safety. However, it is still desirable to improve the rate performance by improving the Zn (de)intercalation kinetics and long-cycle stability by eliminating the dendrite formation problem. Herein, the first paradigm of a high-rate and ultrastable flexible quasi-solid-state zinc-ion battery is constructed from a novel 2D ultrathin layered zinc orthovanadate array cathode, a Zn array anode supported by a conductive porous graphene foam, and a gel electrolyte. The nanoarray structure for both electrodes assures the high rate capability and alleviates the dendrite growth. The flexible Zn-ion battery has a depth of discharge of ≈100% for the cathode and 66% for the anode, and delivers an impressive high-rate of 50 C (discharge in 60 s), long-term durability of 2000 cycles at 20 C, and unprecedented energy density ≈115 Wh kg , together with a peak power density ≈5.1 kW kg (calculation includes masses of cathode, anode, and current collectors). First principles calculations and quantitative kinetics analysis show that the high-rate and stable properties are correlated with the 2D fast ion-migration pathways and the introduced intercalation pseudocapacitance.

Low-dimensional organic−inorganic metal halide hybrids (OIMHs) with an ultrabroad-band emission are promising as downconversion phosphors for solid-state lighting. However, toxicity of Pb and low photoluminescence quantum efficiency (PLQE) hamper their application. Herein, two zero-dimensional (0D) lead-free organic antimony (Sb) chloride (Cl) hybrids with dual-band emissions and PLQEs: (TTA) 2 SbCl 5 (TTA = tetraethylammonium) and (TEBA) 2 SbCl 5 (TEBA = benzyltriethylammonium) are reported. Both compounds show a single broad-band orange emission with a near-unity PLQE upon low-energy photons (e.g., 360 nm) excitation. The dual-band emission with an additional blue emission band upon high-energy photons (e.g., 300 nm) excitation enable (TTA) 2 SbCl 5 to be a single-component phosphor for white light emission with a PLQE of 68%, correlated color temperature (CCT) of 2360 K and color rendering index (CRI) of 84. Based on photoluminescence spectra measurements and density functional theory calculations, the dual-band emission is assigned to the radiative recombination from both singlet and triplet self-trapped excitons in inorganic [SbCl 5 ] 2− pyramids. In addition, both luminescent compounds exhibit excellent stability against humidity and thermal attacks. Using (TEBA) 2 SbCl 5 as a yellow downconversion material, highly stable white-light-emitting diodes with a Commission Internationale de l'Eclairage (CIE) of (0.36, 0.33), CCT of 4282 K, and CRI of 82 were demonstrated. These results validate that the title 0D lead-free OIMHs with a dual-band emission and a near-unity PLQE are promising luminescent materials for solid-state lighting.

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Many species in nature have evolved remarkable strategies to visually adapt to the surroundings for the purpose of protection and predation. Similarly, acquiring the capabilities of adaptively camouflaging in the infrared (IR) spectrum has emerged as an intriguing but highly challenging technology in recent years. Here, we report adaptive thermal camouflage devices by bridging the optical and radiative properties of nanoscopic platinum (Pt) films and silver (Ag) electrodeposited Pt films. Specifically, these metal-based devices have large, uniform, and consistent IR tunabilities in mid-wave IR (MWIR) and long-wave IR (LWIR) atmospheric transmission windows (ATWs). Furthermore, these devices can be easily multiplexed, enlarged, applied to rough and flexible substrates, or colored, demonstrating their multiple adaptive camouflaging capabilities. We believe that this technology will be advantageous not only in various adaptive camouflage platforms but also in many thermal radiation management–related technologies.

Aqueous rechargeable Zn–MnOx batteries are very attractive due to their low‐cost and high energy density. However, Mn(III) disproportionation and Jahn–Teller distortion can induce Mn(II) dissolution and irreversible phase changes, greatly deteriorating the cycling life. Herein, a multi‐valence cobalt‐doped Mn3O4 (Co‐Mn3O4) with high capacity and reversibility, which lies in the multiple roles of the various states of doped cobalt, is reported. The Co2+ doping between the phase change product δ‐MnO2 layer acts as a “structural pillar,” and the Co4+ in the layer can increase the conductivity of Mn4+ and hold the high specific capacity. More importantly, Co ion (Co2+, Co3+) doping can effectively inhibit the Jahn–Teller effect in discharge products and promote ion diffusion. Using X‐ray absorption spectra results and density functional theory modelling, the multiple roles of doped cobalt are verified. Specifically, the Co‐Mn3O4 cathode shows high specific capacity of 362 mAh g–1 and energy density of 463.1 Wh kg–1 at 100 mA g–1. After 1100 cycles at 2.0 A g–1, the capacity retention rate reaches 80%. This work brings a new idea and approach to the design of highly reversible Mn‐based oxides cathode materials for Zn‐ion batteries.

Potassium‐intercalated graphite intercalation compounds (K‐GICs) are of particular physical and chemical interest due to their versatile structures and fascinating properties. Fundamental insights into the K+ storage mechanism, and the complex kinetics/thermodynamics that control the reactions and structural rearrangements allow manipulating K‐GICs with desired functionalities. Here operando studies including in situ Raman mapping and in situ X‐ray diffraction (XRD) characterizations, in combination with density‐functional theory simulations are carried out to correlate the real‐time electrochemical K+ intercalation/deintercalation process with structure/component evolution. The experimental results, together with theoretical calculations, reveal the reversible K‐GICs staging transition: C ↔ stage 5 (KC60) ↔ stage 4 (KC48) ↔ stage 3 (KC36) ↔ stage 2 (KC24/KC16) ↔ stage 1 (KC8). Moreover, the staging transition is clearly visualized and an intermediate phase of stage 2 with the stoichiometric formula of KC16 is identified. The staging transition mechanism involving both intrastage transition from KC24 (stage 2) to KC16 (stage 2) and interstage transition is proposed. The present study promotes better fundamental understanding of K+ storage behavior in graphite, develops a nondestructive technological basis for accurately capture nonuniformity in electrode phase evolution across the length scale of graphite domains, and offers guidance for efficient research in other GICs.