| The commercialization of lithium-ion batteries(LIBs)has undoubtedly contributed to the reformation of wireless communication and fossil fuel-free society,however,due to the limited specific capacity of graphite anode,the increasing rate of LIBs in energy density is gradually lagging behind the rapidly growing energy demand of society.Therefore,exploring the next generation of high specific energy batteries to replace LIBs is particularly vital to satisfy the high energy need of the emerging electric vehicle and electronic information industries.Lithium metal anode with ultra-high theoretical specific capacity,which can meet the design requirements of next-generation 500 Wh kg-1 high-energy batteries,is expected to replace conventional graphite anode to further increase the energy density of rechargeable lithium batteries.Nevertheless,the problems of uncontrolled Li dendrite growth and infinite volume change exhibited in lithium metal anode during cycling seriously hinder its practical applications.Thus,understanding the nucleation,growth and failure mechanism of Li metal and taking effective measures to suppress Li dendrites can help promote the progress of lithium metal anode for commercial applications.In this paper,the surface modification of the host for lithium metal anode is used to improve its Li affinity,promote the uniform deposition of Li metal,and alleviate Li dendritic problems,thus can stabilize the lithium metal anode.The effect of surface structure and Li affinity the host for the host on the deposition of lithium metal and the electrochemical performance of the composite lithium anode are investigated,and the main findings are as follows:1.Surface modification of metal-based 3D Cu mesh(CuM)host by MOF-derived method was developed.The Cu-MOF-derived N-doped carbon nanowire arrays(NC NWAs)further increased the active specific surface area of the hosts and the nucleation barrier of lithium on the hosts.The modified CuM host can cycled stably for more than 400 cycles with a high coulomb efficiency(CE)of over 98%at the current density of 2 m A cm-2,while the CuM@NC NWAs@Li composite lithium anode prepared with the modified CuM host cycled stably for more than 190 h with a low voltage hysteresis of 45 m V at the current density of 10 m A cm-2.2.CuM was modified by introducing a strong lithiophilic oxide layer through a simple air-fired heat treatment.Compared with the N-functional groups,the lithiation reaction of the lithiophilic oxide with Li can significantly lower the nucleation barrier of Li on the host,so the modified CuM showed an extremely low nucleation overpotential.Since the morphology of lithiophilic oxide also played an important role in inducing lithium deposition,CuM-300 host obtained by air-firing at 300°C with a thinner and uniformly morphological oxide layer can prepare dense composite lithium anode with less lithium loss.The CuM-300@Li-10 composite lithium anode prepared from the modified host cycled stably for more than 180 h with a low average overpotential of 48.0 m V at the current density of 10 m A cm-2.3.To obtain a composite lithium anode with higher energy density,the MOF-derived strongly lithophilic ZnO/NC nanosheets were used to surface modify the lightweight 3D flexible carbon cloth(CC)with high structural stability.The uniformly distributed ZnO/NC nanosheets can provide the driving force for infusing the molten Li into the CC skeleton through the lithiation reaction to form a dendrite-free CC@ZnO/NC@Li composite lithium anode with a high capacity lithium loading of 53.8 m Ah cm-2.With the multiple synergies of 3D flexible CC skeleton,the lithiation reactant Li Zn alloy and N-doping,the CC@ZnO/NC@Li anode exhibited excellent cycle stability in the symmetric cell,which can steadily operate for 1000cycles with a very small overpotential at current densities of 2 m A cm-2and 5 m A cm-2.In addition,the CC@ZnO/NC@Li electrode showed superior rate performance in coin full cells and good flexibility in pouch cells. |
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