Facile one-pot synthesis of lithium metal nanoparticles for superior lithium-ion anode applications.

A capable one-step method, femtosecond laser ablation of solids in liquids, was successfully applied to prepare lithium metal nanoparticles to mitigate the initial capacity loss and improve the electrochemical performance of a graphite-based electrode as a Li-host anode. Remarkably, according to the physicochemical characterization, this advanced optical method allowed to obtain uniform spheroidal and crystalline Li nanoparticles with an average particle size <20 nm. These novel ultrafine Li nanoparticles significantly decrease the initial capacity loss of a graphite-based anode, leading to reach high coulombic efficiency (>99 %), good specific charge capacity (322 mAh/g), and superior capacity retention (96 %) at an applied current density of 100 mA g-1 after 200 cycles.

Influence of the fluoroethylene carbonate on the electrochemical behavior of Bi3Ge4O12 as Lithium-ion anode.

Systematic ex-situ X-ray diffraction (XRD) characterization and electrochemical study revealed the key roles that the cut-off voltage and fluoroethylene carbonate (FEC) additive play on improving electrochemical performance of the Bi3Ge4O12-based (BGO) electrode. The ex-situ XRD analysis revealed that BGO particles suffer multiphase transitions during the (dis)charge reactions, being observed some phases as Bi2O2.33, BiLi3, Li2O, Ge4Li15, Ge2Li7, Ge3Li7, Ge5Li22, Ge4Li9, Bi2O3 and GeO2. The electrochemical evaluation exhibited that the addition of 5 v/v% of FEC in 1.0 M lithium hexafluorophosphate (LiPF6) in ethylene carbonate and diethyl carbonate (EC: DEC) at an applied cut-off voltage (1.5 V vs Li/Li+) improves the specific capacity (29%, delivering 479 mAh g-1), capacity retention (12%) and rate capability (369 mAh g-1 at 1000 mA g-1) of the BGO-based electrode. Also, FEC promotes the formation of a stable solid-electrolyte interface (SEI) layer on the anode at a cut-off voltage of 1.5 V vs Li/Li+. It displays the lowest values of SEI and charge transfer (CT) resistances, and electrode polarization, improving the reversibility of the alloying reactions related to Ge-Li and Bi-Li and maintaining their redox activity after 100 cycles, according to dQ dV-1 data.