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 neuronmimic anode for lithium-ion batteries. The 2D assembly well retains the tap density advantage derived from the micronstar 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.

Achieving Fast and Durable Lithium Storage through Amorphous FeP Nanoparticles Encapsulated in Ultrathin 3D P-Doped Porous Carbon Nanosheets

“…Figure b exhibits the charge–discharge profiles of the as-synthesized FeP@CNs electrode at a current density of 0.2 A g –1 in the potential range of 0.01–3 V. The discharge and charge capacities of the first cycle are 1185 and 795 mA h g –1 , respectively, corresponding to a first cycle Coulombic efficiency (CE) of 67.1%. The initial capacity loss is primarily due to the inevitable formation of SEI films, − which can be compensated by prelithiating the anodes through either chemical or electrochemical methods or by adding stabilized Li metal powders into the anodes. − The CE value then quickly increases to 95.4% at the second cycle and levels off at 97–99% in subsequent cycles. Figure c presents the cycling performance of FeP@CNs electrode at 0.2 A g –1 .…”

“…Generally, a constant b value approaching 0.5 or 1 indicates a diffusioncontrolled or capacitance-controlled process, respectively. 62,79 By plotting the linear relationship between log(i) and log(v), the calculated b values (Figure S18) determined by the anodic (peak 1 and peak 2) and cathodic (peak 3 and peak 4) slopes are 0.83, 0.83, 1.00 and 0.87, respectively, suggesting a hybrid Li storage mechanism that is dominated by a capacitancecontrolled process. By distinguishing the current (i) from the diffusion and capacitance according to eq 2, the ratios of capacitive contribution are further determined quantitatively.…”

“…In general, the voltammetric response of an electrode-active material at various sweep rates can be qualitatively measured by the relationship between the peak current ( i ) and scan rate ( v ) from CV curves according to where a and b and k 1 and k 2 are adjustable parameters and constant parameters, respectively. ,,, The b value can be calculated by plotting log­( i ) versus log­( v ). Generally, a constant b value approaching 0.5 or 1 indicates a diffusion-controlled or capacitance-controlled process, respectively. , By plotting the linear relationship between log­( i ) and log­( v ), the calculated b values (Figure S18) determined by the anodic (peak 1 and peak 2) and cathodic (peak 3 and peak 4) slopes are 0.83, 0.83, 1.00 and 0.87, respectively, suggesting a hybrid Li storage mechanism that is dominated by a capacitance-controlled process. By distinguishing the current ( i ) from the diffusion and capacitance according to eq , the ratios of capacitive contribution are further determined quantitatively.…”

Metal–Organic Framework-Derived Hierarchical MnO/Co with Oxygen Vacancies toward Elevated-Temperature Li-Ion Battery

“…However, TMO anodes do not contain lithium within their pristine crystal, which the high specific surface area- and SEI-consumed lithium from cathode result in high irreversible capacity loss and thus low initial Coulombic efficiency (CE). Thus, surface chemistry or prelithiation methods (chemical reaction with n -butylithium, electrochemical prelithiation, direct contact with lithium strips/foil, and pretreatment with LiCl or stabilized lithium metal powder) have been proposed to handle this inevitable issue for conversion-type TMO anodes. , Among a variety of TMOs, MnO achieves a high theoretical capacity (755 mAh g –1 ), low electromotive force value (1.032 V vs. Li/Li + ), high density (5.43 g cm –3 ), less volume expansion (∼171%), and the lowest voltage hysteresis (<0.7 V), making it a promising candidate for high volumetric electrochemical performance. , Nevertheless, intrinsically inferior electrical conductivity, low initial Coulombic efficiency, and internal structural reorganizations incur severe capacity attenuation and deteriorative cyclic stability, thus thwarting their practical implementation as advanced electrode materials. − …”

Pseudocapacitive sodium storage of Fe1−xS@N-doped carbon for low-temperature operation

“…Nevertheless, it has been noticed that the unsatisfactory electronic conductivity, sluggish Na + diffusion kinetics, and obvious volume variation of Fe 1−x S undermine their effectiveness to present excellent performance, especially under lowtemperature conditions [14][15][16][17]. Designing elegant nanostructures, constructing hybrid composites with conductive carbon, and heteroatom doping are effective strategies used to address these issues [18][19][20]. Liu et al [21] achieved a satisfactory capacity of 573 mA h g −1 at 0.1 A g −1 for Fe 1−x S@PCNWs/rGO composite.…”