Abstract:
Lithium nitrate is an attractive lithium additive in the construction of high-performance lithium metal anodes with a Li3N-rich solid electrolyte interphase (SEI) layer. However, the eight-electron transfer process induces high energy barriers between LiNO3 and Li3N. Herein, the inner Helmholtz plane is tuned on a Li deposition host to attain sluggish/rapid LiNO3 decomposition kinetics, resulting in different intermediate content distributions of Li species in the SEI. Notably, lithium oxynitride (LiNO) is identified as the decomposition intermediate, and experimental and simulation results confirm its role in obstructing LiNO3 decomposition. Moreover, the results reveal that the dipole–dipole interaction between LiNO and the polar V≡N bond can change the ionic/covalent character of the N═O bonds, considerably facilitating the energy transfer process of the N═O cleavage, and promoting a LiNO3 reduction to achieve a Li3N-rich SEI. Consequently, when the electrolyte contains 0.37 m LiNO3, dendrite, and dead Li formation are suppressed effectively with the VN system, and an average Coulombic efficiency of 99.7% over 1000 cycles (1 mA cm−2, 1 mAh cm−2) can be attained. These results can promote the nitride oxidation break process and pave the way for fabricating high-performance Li3N-rich lithium metal batteries.
