Search for: All records

Abstract Constructing an artificial solid electrolyte interphase (SEI) on lithium metal electrodes is a promising approach to address the rampant growth of dangerous lithium morphologies (dendritic and dead Li⁰) and low Coulombic efficiency that plague development of lithium metal batteries, but how Li⁺transport behavior in the SEI is coupled with mechanical properties remains unknown. We demonstrate here a facile and scalable solution-processed approach to form a Li₃N-rich SEI with a phase-pure crystalline structure that minimizes the diffusion energy barrier of Li⁺across the SEI. Compared with a polycrystalline Li₃N SEI obtained from conventional practice, the phase-pure/single crystalline Li₃N-rich SEI constitutes an interphase of high mechanical strength and low Li⁺diffusion barrier. We elucidate the correlation among Li⁺transference number, diffusion behavior, concentration gradient, and the stability of the lithium metal electrode by integrating phase field simulations with experiments. We demonstrate improved reversibility and charge/discharge cycling behaviors for both symmetric cells and full lithium-metal batteries constructed with this Li₃N-rich SEI. These studies may cast new insight into the design and engineering of an ideal artificial SEI for stable and high-performance lithium metal batteries. 

Metallic sulfide anodes show great promise for sodium‐ion batteries due to their high theoretic capacities. However, their practical application is greatly hampered by poor electrochemical performance because of the large volume expansion of the sulfides and the sluggish kinetics of the Na⁺ions. Herein, a porous bimetallic sulfide of the SnS/Sb₂S₃heterostructure is constructed that is encapsulated in the sulfur and nitrogen codoped carbon matrix (SnS/Sb₂S₃@SNC) by a facile and scalable method. The porous structure can provide void space to alleviate the volume expansion upon cycling, guaranteeing excellent structural stability. The unique heterostructure and the S, N codoped carbon matrix together facilitate fast‐charge transport to improve reaction kinetics. Benefitting from these merits, the SnS/Sb₂S₃@SNC electrode exhibits high capacities of 425 mA h g⁻¹at 200 mA g⁻¹after 100 cycles, and 302 mA h g⁻¹at 500 mA g⁻¹after 400 cycles. Moreover, the SnS/Sb₂S₃@SNC anode shows an outstanding rate performance with a capacity of over 200 mA h g⁻¹at a high current density of 5000 mA g⁻¹. This study provides a new strategy and insight into the design of electrode materials with the potential for the practical realization and applications of next‐generation batteries.