Nowadays, lithium-ion batteries (LIBs) have been widely used in portable electronics, electric vehicles, and grid energy storage systems. [1][2][3] However, the traditional LIBs based on graphite anode cannot satisfy the ever growing energy density demands. [4,5] In this background, next-generation Li-ion batteries based on Li metal anode with ultrahigh energy density have attracted worldwide attention in recent years, such as lithium-sulfur (2600 Wh kg −1 ), Li-O 2 batteries (3580 Wh kg −1 ). [6][7][8] Li metal anode with high theoretical specific capacity (3860 mAh g −1 ), low density (0.534 g cm −3 ), and the lowest potential (−3.040 V vs standard hydrogen electrode) demonstrated remarkable advantages in energy density as anode for Li metal batteries (LMBs). [9][10][11][12][13][14] However, the practical application of Li metal anode in LMBs is still suffering from low coulombic efficiency (CE), poor cycle life, and safety concerns because of serious Li dendrite growth during cycling. [15][16][17] The uncontrollable dendrite growth leads to the formation of "dead lithium" with low coulombic efficiency, and may even cause catastrophic failure of battery by internal short circuit. [18][19][20] During the past decade, there are majorly two kinds of strategies proposed to suppress dendrite growth and protect lithium metal anode. The first approach is based on a mechanical blocking strategy, such as, 1) optimization of the solid electrolyte interface (SEI) layer and improving its mechanical modulus and stability, for which LiF, [21][22][23] Li 3 N, [24] Li 2 S, [25][26][27] Li 3 PO 4 , [28] Li 2 O, [29] etc. have been introduced into the SEI layer and showed an improved cycling performance at 1.0-2.0 mA cm −2 ; 2) introducing an extra coating layer (poly(dimethylsiloxane), [30] hollow carbon spheres, [31] artificial solid electrolyte layer, [32] etc.) as a protecting layer on the surface of Li metal. The other approach is focused on designing various nanostructures to control the electric field distribution and accommodate volume expansion. In which, hierarchical frameworks such as 3D carbon fiber cloth, [33] Ni foam, [34] and 3D porous Cu foil [35,36] have been constructed to store Li metal and inhibit the growth of Li dendrites. However, these two strategies were both converged at inhibiting lithium deposition, which have not changed the fundamental, self-amplification behavior of the dendrite growth. Moreover, they failed to support the practical application of Li-S or Li-O 2 Uncontrollable Li dendrite growth and low Coulombic efficiency severely hinder the application of lithium metal batteries. Although a lot of approaches have been developed to control Li deposition, most of them are based on inhibiting lithium deposition on protrusions, which can suppress Li dendrite growth at low current density, but is inefficient for practical battery applications, with high current density and large area capacity. Here, a novel leveling mechanism based on accelerating Li growth in concave fashion is proposed, which ena...

Practical applications of lithium metal anodes are gravely impeded by inhomogeneous lithium deposition, which results in dendrite growth. Electrolyte additives are proven to be effective in improving performance but usually serve only a single function. Herein, nitrofullerene is introduced as a bifunctional additive with a smoothing effect and forms a protective solid electrolyte interphase (SEI) layer on stable lithium metal anodes. By design, nitro-C 60 can gather on electrode protuberances via electrostatic interactions and then be reduced to NO 2 − and insoluble C 60 . Next, the C 60 anchors on the uneven groove of the lithium surface, resulting in a homogeneous distribution of Li ions. Finally, NO 2 − anions can react with metallic Li to build a compact and stable SEI with high ion transport. With a 5 mM nitro-C 60 additive, Li−Li symmetric cells show superior cycle stability in both carbonate and ether electrolytes, Li−sulfur batteries with a high cathode loading (10.6 mg cm −2 , 6 mAh cm −2 ) can achieve improved cycle retention of 63.2% over 100 cycles in a carbonate electrolyte, and full cells paired with a high-areal-capacity LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode (3.5 mAh cm −2 ) exhibit a significantly enhanced cycle lifespan even under lean electrolyte conditions.

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The rational design and controllable fabrication of electrode materials with tailored structures and superior performance is highly desirable for the next-generation lithium ion batteries (LIBs). In this work, a novel three-dimensional (3D) graphite foam (GF)@SnO nanorod arrays (NRAs)@polyaniline (PANI) hybrid architecture was constructed via solvothermal growth followed by electrochemical deposition. Aligned SnO NRAs were uniformly grown on the surface of GF, and a PANI shell with a thickness of ∼40 nm was coated on individual SnO nanorods, forming a SnO@PANI core-shell structure. Benefiting from the synergetic effect of 3D GF with large surface area and high conductivity, SnO NRAs offering direct pathways for electrons and lithium ions, and the conductive PANI shell that accommodates the large volume variation of SnO, the binder-free, integrated GF@SnO NRAs@PANI electrode for LIBs exhibited high capacity, excellent rate capability, and good electrochemical stability. A high discharge capacity of 540 mAh g (calculated by the total mass of the electrode) was achieved after 50 cycles at a current density of 500 mA g. Moreover, the electrode demonstrated superior rate performance with a discharge capacity of 414 mAh g at a high rate of 3 A g.

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Through in situ quantization, Fe3O4 was uniformly dispersed in 3D microcarbon matrices of ultrafast and stable sodium ion batteries.