energy density, and cost effective. Albertus et al. have advocated for the use of limited lithium (≤30 µm) to ensure early identification of technical challenges associated with stable and dendrite-free cycling and a more rapid transition to commercially relevant designs. [7] And recently, Liu et al. [8] re-emphasized the importance of limited lithium and announced that 50 µm Li anode was required to reach a high energy of 300 Wh kg −1. Therefore, for practical lithium-metal batteries (LMBs), the utilization of thin Li metal anode with thicknesses <30 µm (<6 mAh cm −2) is extremely necessary. [6-10] In other words, the negative to positive electrode capacity ratio (N/P ratio) must be strictly restricted. Limiting the amount of Li metal anode is a great challenge, since it is highly reactive. The continuous reaction of Li metal with electrolyte to generate a solid electrolyte interphase (SEI) as well as the uneven Li platting to form dendrite growth and pulverized Li metal, which cause fast consumptions of Li metal and electrolyte, low Coulombic efficiency (CE), and short lifespan of LMBs. To improve cycling stability of Li metal anode in organic liquid electrolyte, various attempts have already been made, including highly concentrated electrolyte, [11] electrolyte additives, [12,13] external pressure, [14,15] Li host, [16,17] and surface coating. [18,19] While most of the above strategies use unlimited Li foil, only a few studies focus on limiting the amount of Li metal for LMBs. [6,9,20,21] For example, Niu et al. reported a self-smoothing Li-carbon anode based on the host of mesoporous carbon nanofibers and a high-energy LMB with a low N/P ratio of ≤2. [6] Archer's group and Cho's group achieved stable operations of LMBs composed of a high-loading cathode and a thin Li anode (20 µm) with Langmuir-Blodgett artificial SEIs. [9] While, compared with liquid electrolyte, some types of solid electrolytes are less reactive with Li metal, which may be good candidates for LMBs with low N/P ratios. [22] Additionally, the safety of LMBs can be greatly improved by replacing flammable liquid electrolyte with solid electrolyte. [23] But, up to now, there are only a few researches about all-solidstate lithium-metal batteries (ASSLMBs) using limited amount of Li metal anode. A recent work reported an ASSLMB with Li 6 PSCl sulfide electrolyte and Ag-C composite anode with no excess Li. [24] Besides, the studies of LiPON-based thin-film batteries with limited Li metal have been reported, which are Metallic lithium (Li), considered as the ultimate anode, is expected to promise high-energy rechargeable batteries. However, owing to the continuous Li consumption during the repeated Li plating/stripping cycling, excess amount of the Li metal anode is commonly utilized in lithium-metal batteries (LMBs), leading to reduced energy density and increased cost. Here, an all-solid-state lithium-metal battery (ASSLMB) based on a garnet-oxide solid electrolyte with an ultralow negative/positive electrode capacity ratio (N/P ratio) is reported...

Solar-blind photodetectors have captured intense attention due to their high significance in ultraviolet astronomy and biological detection. However, most of the solar-blind photodetectors have not shown extraordinary advantages in weak light signal detection because the forewarning of low-dose deep-ultraviolet radiation is so important for the human immune system. In this study, a high-performance solar-blind photodetector is constructed based on the n-Ga2O3/p-CuSCN core–shell microwire heterojunction by a simple immersion method. In comparison with the single device of the Ga2O3 and CuSCN, the heterojunction photodetector demonstrates an enhanced photoelectric performance with an ultralow dark current of 1.03 pA, high photo-to-dark current ratio of 4.14 × 104, and high rejection ratio (R 254/R 365) of 1.15 × 104 under a bias of 5 V. Excitingly, the heterostructure photodetector shows high sensitivity to the weak signal (1.5 μW/cm2) of deep ultraviolet and high-resolution detection to the subtle change of signal intensity (1.0 μW/cm2). Under the illumination with 254 nm light at 5 V, the photodetector shows a large responsivity of 13.3 mA/W, superb detectivity of 9.43 × 1011 Jones, and fast response speed with a rise time of 62 ms and decay time of 35 ms. Additionally, the photodetector can work without an external power supply and has specific solar-blind spectrum selectivity as well as excellent stability even through 1 month of storage. Such prominent photodetection, profited by the novel geometric construction and the built-in electric field originating from the p–n heterojunction, meets greatly well the “5S” requirements of the photodetector for practical application.

Lithium-ion batteries have undergone a remarkable development in the past 30 years. However, conventional electrodes are insufficient for the everincreasing demand of high-energy batteries. Here, reported is a thick electrode with a dense structure, as an alternative to the commonly recognized porous framework. A low-temperature sintering technology with the aid of aqueous solvent, high pressure, and an ion-conductive additive is originally developed for preparing the LiCoO 2 (LCO)/Li 4 Ti 5 O 12 (LTO) dense-structure electrode as the representative cathode/anode material. The 400 µm thick cathode with 110 mg cm −2 mass loading achieves a high specific capacity of 131.2 mAh g −1 with a good capacity retention of 96% over 150 cycles, far exceeding the commercial counterpart (≈40 µm) of 54.1 mAh g −1 with 39%. The ultrathick electrode of 1300 µm thickness presents a remarkable area capacity of 28.6 mAh cm −2 that is 16 times that of the commercial electrode. The full cell based on the dense electrodes delivers an extremely high areal capacity of 14.4 mAh cm −2 . The ion-diffusion coefficients of the densely sintered electrodes increase by nearly three orders of magnitude. This design opens up a new avenue for scalable and sustainable material manufacturing towards various practical applications.

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Rechargeable batteries that combine high energy density with high power density are highly demanded. However, the wide utilization of lithium metal anode is limited by the uncontrollable dendrite growth, and the conventional lithium-ion batteries (LIBs) commonly suffer from low rate capability. Here, we for the first time develop a biofilm-coated separator for high-energy and high-power batteries. It reveals that the coating of Escherichia coli protein nanofibers can improve electrolyte wettability and lithium transference number and enhance adhesion between separators and electrodes. Thus, lithium dendrite growth is impeded because of the uniform distribution of the Li-ion flux. The modified separator also enables the stable cycling of high-voltage Li|Li1.2Mn0.6Ni0.2O2 (LNMO) cells at an extremely high rate of 20 C, delivering a high specific capacity of 83.1 mA h g–1, which exceeds the conventional counterpart. In addition, the modified separator in the Li4Ti5O12|LNMO full cell also exhibits a larger capacity of 68.2 mA h g–1 at 10 C than the uncoated separator of 37.4 mA h g–1. Such remarkable performances of the modified separators arise from the conformal, adhesive, and endurable coating of biofilm nanofibers. Our work opens up a new opportunity for protein-based biomaterials in practical application of high-energy and high-power batteries.