In situ regulation of dendrite-free lithium anode by improved solid electrolyte interface with defect-rich boron nitride quantum dots

Abstract

The development of effective solid electrolyte interface (SEI) on anode interfaces is critical for ensuring the stability of Li metal batteries. However, uneven Li-ion transfer resulting from the compositional inhomogeneity of natural SEI aggravates dendrite formation. To alleviate this problem, a novel strategy of in situ regulation using rigid boron nitride quantum dots (BNQDs) was proposed to adjust the Li metal interface SEI. The chemistry and conductive inertia of BN effectively protected Li metal with minimized parasitic reactions. Defect-rich BNQDs exhibited a strong Li-ion affinity, which resulted in a homogeneous ion flux and dendrite-free deposition. This flat anode considerably improved electrochemical interface stability. Therefore, Li/Li symmetric cells using BNQDs exhibited enhanced cycle performance with a high capacity of 4 mA h cm⁻². Coupled with a sulfur cathode, a low negative-to-positive capacity ratio of approximately 3.6 : 1 full Li–S cell exhibited a stable coulombic efficiency over 400 cycles.