RESUMEN
The integration of a solid electrolyte with electrodes without interfacial degradation is an integral part of enabling high-performance all-solid-state batteries. Here we highlight that additive-assisted solid-state reactions using high-energy ball-milling and multistep heating can be an effective approach to lower the processing temperatures of cubic Li7La3Zr2O12 garnet. The obtained total Li conductivity is 1.4 × 10-4 S cm-1, comparable with that obtained using high-temperature processing. We found that liquid-phase sintering triggered by a lithium borate additive increases the microstrain of Li7La3Zr2O12, increasing Li conductivity. Our work demonstrates the feasibility to engineer conventional ceramics processing to sustainably produce all-solid-state batteries with a low thermal budget in practice.
RESUMEN
Assembling all-solid-state batteries presents a unique challenge due to chemical and electrochemical complexities of interfaces between a solid electrolyte and electrodes. While the interface stability is dictated by thermodynamics, making use of passivation materials often delays interfacial degradation and extends the cycle life of all-solid cells. In this work, we investigated antiperovskite lithium oxychloride, Li3OCl, as a promising passivation material that can engineer the properties of solid electrolyte-Li metal interfaces. Our experiment to obtain stoichiometric Li3OCl focuses on how the starting ratios of lithium and chlorine and mechanochemical activation affect the phase stability. For substantial LiCl excess conditions, the antiperovskite phase was found to form by simple melt-quenching and subsequent high-energy ball-milling. Li3OCl prepared with 100% excess LiCl exhibits ionic conductivity of 3.2 × 10-5 S cm-1 at room temperature, as well as cathodic stability against Li metal upon the extended number of cycling. With a conductivity comparable to other passivation layers, and stable interface properties, our Li3OCl/LiCl composite has the potential to stably passivate the solid-solid interfaces in all-solid-state batteries.
RESUMEN
Recent studies on supercapacitors have focused on the development of hierarchical nanostructured carbons by combining two-dimensional graphene and other conductive sp(2) carbons, which differ in dimensionality, to improve their electrochemical performance. Herein, we report a strategy for synthesizing a hierarchical graphene-based carbon material, which we shall refer to as spine-like nanostructured carbon, from a one-dimensional graphitic carbon nanofiber by controlling the local graphene/graphitic structure via an expanding process and a co-solvent exfoliation method. Spine-like nanostructured carbon has a unique hierarchical structure of partially exfoliated graphitic blocks interconnected by thin graphene sheets in the same manner as in the case of ligaments. Owing to the exposed graphene layers and interconnected sp(2) carbon structure, this hierarchical nanostructured carbon possesses a large, electrochemically accessible surface area with high electrical conductivity and exhibits high electrochemical performance.
RESUMEN
A multiphase composite film composed of nickel(II) hydroxide and cobalt(II) hydroxide was synthesized by a novel co-precipitation method. The film exhibited high capacitance and stable cyclic retention because of its 3D network nanostructure and high conductivity due to CoOOH evolved during cycling.