In Situ-Constructed Multifunctional Composite Anode with Ultralong-Life Toward Advanced Lithium-Metal Batteries.

Metallic lithium is the most competitive anode material for next-generation high-energy batteries. Nevertheless, the extensive volume expansion and uncontrolled Li dendrite growth of lithium metal not only cause potential safety hazards but also lead to low Coulombic efficiency and inferior cycling lifespan for Li metal batteries. Herein, a multifunctional dendrite-free composite anode (Li/SnS2) is proposed through an in situ melt-infusion strategy. In this configuration, the 3D cross-linked porous Li2S/Li22Sn5 framework facilitates the rapid penetration of electrolytes and accommodates the volume expansion during the repeated Li-plating process. Meanwhile, the lithiophilic Li2S phases with a low Li+ transport barrier ensure preferential Li deposition, effectively avoiding uneven electron distribution. Moreover, the Li22Sn5 electron conductors with appropriate Li+ bonding ability guarantee rapid charge transport and mass transfer. Most importantly, the steady multifunctional skeleton with sufficient inner interfaces (Li2S/Li22Sn5) in the whole electrode, not only realizes the redistribution of the localized free electron, contributing to the decomposition of Li clusters, but also induces a planar deposition model, thus restraining the generation of Li dendrites. Consequently, an unprecedented cyclability of over 6 500 h under an ultrahigh areal capacity of 10 mAh cm-2 and a current rate of 20 mA cm-2 is achieved for the prepared Li2S/Li22Sn5 composite anode. Moreover, the assembled Li/SnS2||LiFePO4 (LFP) pouch full-cells also demonstrate remarkable rate capability and a convincing cycling lifespan of more than 2 000 cycles at 2 C.

Ultrahigh initial coulombic efficiency for deep sodium storage enabled by carbon-free vanadium-doping MoS2 hierarchical nanostructure.

Molybdenum disulfide (MoS2) has garnered attention as a promising anode material for sodium-ion batteries due to its high theoretical capacity and unique lamellar texture. Nevertheless, unmodified MoS2 suffers from inferior electrical conductivity, poor reaction reversibility, and suboptimal cycle life upon repeated sodiation/desodiation. In this study, a novel carbon-free V-heteroatom doping MoS2 composite (abbr. VMS) with hierarchical laurustinus-like structure was synthesized by a facile one-step hydrothermal process. Specifically, the rational doping of V-atoms can effectively modulate the intrinsic electronic structure of pure MoS2, resulting in enhanced Na-ion diffusion rate, improved reaction kinetics and reduced activation energy compared to bare MoS2. Additionally, the hierarchical structure of the VMS composite, with sufficient spacing, effectively mitigates mechanical stress and ensures the integrity of active materials. Consequently, the prepared VMS composite possesses exceptional reaction reversibility (average ICE value of 92 %) and remarkable capacity retention (92.1 % after 450 cycles at 10 A/g). These findings contribute valuable insights into the development of advanced MoS2-based anode for sodium ion batteries.