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Adv Mater ; 34(38): e2205677, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35924314


The lithium (Li)-metal anode offers a promising solution for high-energy-density lithium-metal batteries (LMBs). However, the significant volume expansion of the Li metal during charging results in poor cycling stability as a result of the dendritic deposition and broken solid electrolyte interphase. Herein, a facile one-step roll-to-roll fabrication of a zero-volume-expansion Li-metal-composite anode (zeroVE-Li) is proposed to realize high-energy-density LMBs with outstanding electrochemical and mechanical stability. The zeroVE-Li possesses a sandwich-like trilayer structure, which consists of an upper electron-insulating layer and a bottom lithiophilic layer that synergistically guides the Li deposition from the bottom up, and a middle porous layer that eliminates volume expansion. This sandwich structure eliminates dendrite formation, prevents volume change during cycling, and provides outstanding flexibility to the Li-metal anode even at a practical areal capacity over 3.0 mAh cm-2 . Pairing zeroVE-Li with a commercial NMC811 or LCO cathode, flexible LMBs that offer a record-breaking figure of merit (FOM, 45.6), large whole-cell energy density (375 Wh L-1 , based on the volume of the anode, separator, cathode, and package), high-capacity retention (> 99.8% per cycle), and remarkable mechanical robustness under practical conditions are demonstrated.

Adv Mater ; 32(42): e2004793, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32930460


Lithium (Li) metal offers the highest projected energy density as a battery anode, however its extremely high reactivity induces dendrite growth and dead Li formation during repeated charge/discharge processes, resulting in both poor reversibility and catastrophic failure. Approaches reported to date often seek to suppress dendrites formation at the expense of energy density. Here, a strategy that resolves the above conflict and achieves a dendrite-free and long-term reversible Li metal anode is reported. A self-organized core-shell composite anode, comprising an outer sheath of lithiated liquid metal (Lix LMy ) and an inner layer of Li metal, is developed, which posesses high electrical and ionic conductivity, and physically separates Li from the electrolyte. The introduction of Lix LMy not only prevents dendrite formation, but also eliminates the use of copper as an inert substrate. Full cells made of such composite anodes and commercially available LiNi0.6 Co0.2 Mn0.2 O2 (NCM622 ) cathodes deliver ultrahigh energy density of 1500 Wh L-1 and 483 Wh kg-1 . The high capacity can be maintained for more than 500 cycles, with fading rate of less than 0.05% per cycle. Pairing with LiNi0.8 Co0.1 Mn0.1 O2 (NCM811 ) further raises the energy density to 1732 Wh L-1 and 514 Wh kg-1 .

Nano Lett ; 20(4): 2724-2732, 2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-32149520


Three-dimensional (3D) lithiophilic host is one of the most effective ways to regulate the Li dendrites and volume change in working Li metal anode. The state-of-the-art 3D lithiophilic hosts are facing one main challenge in that the lithiophilic layer would melt or fall off in high-temperature environment when using the thermal infusion method. Herein, a 3D porous CuZn alloy host containing anchored lithiophilic Zn sites is employed to prestore Li using the thermal infusion strategy, and a 3D composite Li is thus fabricated. Benefiting from the lithiophilic Zn sites with a strong adsorption capacity with Li, which is based on the analyses of the nucleation overpotential, binding energy calculation, and the operando optical observation of Li plating/stripping behaviors, facile uniform Li nucleation and dendrite-free Li deposition could be achieved in the interior of the 3D porous CuZn alloy host and the 3D composite Li shows remarkable enhancement in electrochemical performance.