Shaojie Chen,Jingxuan Zhang,Lu Nie,Xiangchen Hu,Yuanqi Huang,Yi Yu,Wei Liu
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. Compared with the counterpart using a liquid electrolyte at the same low N/P ratios, ASSLMBs show longer cycling life, which is attributed to the higher Coulombic efficiency maintained during cycling. The effect of the species of the interface layer on the cycling performance of ASSLMBs with low N/P ratio is also studied. Importantly, it is demonstrated that the ASSLMB using a limited Li metal anode paired with a LiFePO 4 cathode (5.9 N/P ratio) delivers a stable long-term cycling performance at room temperature. Furthermore, it is revealed that enhanced specific energies for ASSLMBs with low N/P ratios can be further achieved by the use of a high-voltage or high mass-loading cathode. This study sheds light on the practical high-energy all-solid-state batteries under the constrained condition of a limited Li metal anode.
Lithium metal is considered as the ultimate anode for next-generation high energy-density batteries. However, its practical application is still severely hindered by Li dendrite growth as well as infinite volume variation along plating and stripping. Herein, we report a dual-layered, spatially ordered composite skeleton for bottom-up lithium growth by uniformly incorporating Li6.06La3Zr2Al0.2O12 (LLZO) in the upper layer and ZnO in the bottom layer, respectively, in the matrix of carbon fibers (CFs). The well-dispersed ZnO nanoparticles on CFs in the bottom layer function as lithiophilic nucleation sites to homogenize Li nucleation, while LLZO nanoparticles on CFs in the upper layer facilitate Li ion diffusion and distribution for stable lithium growth owing to the high ion conductivity of LLZO. Benefiting from this synergetic effect, the CFs@LLZO//CFs@ZnO composite skeleton can effectively induce Li plating/stripping in a controllable spatially ordered manner, suppressing the volume variation and inhibiting the formation of dendritic lithium. As a result, the symmetric cell using Li|CFs@LLZO//CFs@ZnO||CFs@LLZO//CFs@ZnO|Li presents good cycling stability over 2500 h with a small overpotential of 12 mV at 1 mA cm–2. Notably, under a harsh negative-to-positive N/P ratio of 1, the Li|CFs@LLZO//CFs@ZnO||NCM811 full cell delivers a lifespan of 100 cycles with a capacity fading of only 0.175% per cycle and an average CE of 99.3%.