Neuron-Mimic Smart Electrode: A Two-Dimensional Multiscale Synergistic Strategy for Densely Packed and High-Rate Lithium Storage.

Abstract

Conventional microsized and nanosized secondary battery electrodes inevitably suffer from poor rate capability and low tap density, respectively. Inspired by a multipolar neuron consisting of a centric micron-soma and multiple divergent nanodendrites, we propose a smart electrode design based on a two-dimensional (2D) multiscale synergistic strategy, for addressing both of the above problems. As a proof of concept, multiple Zn-doped Co-based regional-nanoarrays are grown on one Co-doped Zn-based micron-star in a 2D mode via a facile one-pot liquid-phase process, serving as a representative neuron-mimic anode for lithium-ion batteries. The 2D assembly well retains the tap density advantage derived from the micron-star subunit. Combined analysis of three-dimensional tomographic reconstruction, Li-storage kinetics, and in situ transmission electron microscopy reveal a smart electrochemical behavior similar to a neuron working mechanism, which significantly enhances rate capability as compared to the single micron-star subunit. A mutual-doping effect also benefits high-rate lithium storage as verified by density functional theory calculations. As expected, superior reversible areal capacity (2.52 mA h cm-2), high long-term capacity retention (<0.024% loss per cycle over 800 cycles after initial 5 cycles), and enhanced rate capability (1 order of magnitude higher than the microsized electrode) are obtained, accompanied by considerable high-temperature endurance.