PbS nanoparticle aggregates were synthesized in a simple aqueous reaction at room temperature, and were tested as a lithium ion anode material, with a gravimetric capacity of 374 mAh/g at C/2, and a 0.15% capacity loss per cycle. However, its half cell initial Coulombic efficiency (ICE) was only 40%, due to a combination of irreversible Li 2 S and solid electrolyte interface (SEI) formations. A custom controlled prelithiation technique was then applied to the PbS electrodes, converting the active material to Pb/Li 2 S, and consolidating the SEI prior to coin cell assembly. This brought the ICE from 40% to >97%, and allowed for immediate cycling of the electrode at high Coulombic efficiency, without further formation cycles. Upon construction of prelithiated Pb/Li 2 S vs NCM full cells, an 82% ICE was observed, with the majority of the lithium loss from the NCM. The full cells had a combined electrode capacity of 100 mAh/g at C/2.

Lead-based anodes in Li-ion batteries have potential in stationary storage applications, due to their high theoretical volumetric energy density. In this study, the cycle performance of PbO was improved by coating it with a network of graphene oxide sheets, cross-linked by ethylenediamine. The carbon coating reduced electrode capacity degradation from 0.42% to 0.22% per cycle over 200 cycles, increased Coulombic efficiency from 96% to 99%, and increased the accessible capacity of the electrodes through improved electrical connectivity. This low-temperature carbon coating technique is potentially advantageous to other metastable and low-melting electroactive materials.

This paper aims to investigate the mechanism of stress mitigation in micrometer (μm) sized Selenium (Se)-doped Germanium (Ge) electrode, which includes a self-forming inactive Li-Ge-Se network enveloping multiple nanometer-sized crystalline Ge (c-Ge) particles. Considering the electrode system contains multiply active particles, models based on single-particle are unable to fully understand elusive underpinning mechanism. Hence, a phase-field model is employed to investigate the effect of the Li-Ge-Se network on the particle-particle interaction, and the stress variation of the electrode upon lithiation. The amorphous Li-Ge-Se network provides an effective Li diffusion path for inter-particle diffusion, reducing stress difference between the surfaces of neighboring particles. Furthermore, the constraint between the adjacent particles induces a higher compressive stress at the reaction front impeding the mobile Li insertion during lithiation. Though small c-Ge nano-particle in the Ge 0.9 Se 0.1 microparticle is lithiated quickly, the compressive stress is generated at its center for stress equilibrim causing more retardation effect. Meanwhile, the size difference between adjacent particles increases the principle and shear stresses in the inactive Li-Ge-Se, which could potentially lead to mechanical failure and debonding of the amorphous network. We believe that the results of this investigation can shed some light on the optimization design of electrodes.

The erosion mechanism of Li-ion ternary cathode material on Si3N4-SiC and SiO2-SiC refractory slabs was studied at 780 °C for 20h. The results show that the erosion resistance of Si3N4-SiC is much better than that of SiO2-SiC refractory slab after heat treatment for 20h. Erosion mechanism of the two kinds of refractory slabs are different. Inward diffusion of Li2O reacts with a large amount of SiO2 in the SiO2-SiC system. This leads to a large number of reaction products, so that the incompletely reacted SiC particles fall off along with the reaction product, causing the erosion of SiO2-SiC. For Si3N4-SiC, it is mainly because the dense SiO2 protective layer produced by oxidation of Si3N4 prevents further oxidation of Si3N4 and SiC in the system, giving the material excellent erosion resistance.

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