The synthesis of crystalline Ni microwire-nanosheet monolith for recoverable host of dendrite-free Li anode

Abstract

Lithium metal has the highest theoretical energy density and the lowest redox potential among Li-ion battery anodes, but often suffers from Li dendrite-related safety problem. Here, we describe a hierarchical Ni monolith of interconnected crystalline microwires covered with vertical nanosheets synthesized for a recoverable host of dendrite-free Li. The metallic Ni–Li anode exhibits high capacity, high Coulombic efficiency and high-rate cyclability (over 690 cycles at an ultrahigh current density of 40.0 mA cm−2). The Ni monolith, derived from the chain chelation of acetate anions, nickel cations and hydrazine molecules, features high conductivity, high flexibility, low density, hierarchical pores and lithiophilic surface oxidation. This special structure enables fast electrolyte wetting, Li+ flux homogenization and uniform electric field to seed Li metal, which can work as a recyclable, light and conductive host inhibiting dendritic Li growth at various current densities. Our investigation demonstrates that the cheap acetate nickel salt can be used to fabricate nanostructured Li host for Li-ion battery anode.