Construction of Composite Lithium with High Adhesion Work and Fast Ionic Conductivity by Black Phosphorus for Solid-State Lithium Batteries

Abstract

Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO) based solid-state lithium metal batteries (SSLMBs) have a broad application prospect because of the nonflammable nature as well as the high energy density. However, the loose contact and the contact degradation of Li/LLZTO in the stripping process result in the serious lithium dendrites growth. Herein, these issues are addressed by a composite lithium anode (CLA), which is prepared through the reaction between black phosphorus and molten lithium. In comparison to pure lithium, a higher adhesion work (722.67 mJ m^-2) and Li⁺ diffusion coefficient (2.45×10^-12 cm² s^-1) are achieved for CLA, thus assuring the intimate interfacial contact of CLA/LLZTO interface during the lithium stripping process. As a result, a small interfacial resistance of 3.7 Ω cm², a high critical current density of 1.5 mA cm^-2, and extra-long cycle life of 8200 h at 0.3 mA cm^-2 are achieved for CLA symmetric cell at 25 ºC. More importantly, the full cell coupled with high mass loading LiFePO₄ cathode (10.6 mg cm^-2) still shows a large discharge capacity of 156.3 mAh g^-1 and cycles stably at 25 ºC. This work provides an alternative approach to develop the long lifespan and high capacity of SSLMBs.