Pseudocapacitive Na-Ion Storage Boosts High Rate and Areal Capacity of Self-Branched 2D Layered Metal Chalcogenide Nanoarrays

Abstract

The abundant reserve and low cost of sodium have provoked tremendous evolution of Na-ion batteries (SIBs) in the past few years, but their performances are still limited by either the specific capacity or rate capability. Attempts to pursue high rate ability with maintained high capacity in a single electrode remains even more challenging. Here, an elaborate self-branched 2D SnS (B-SnS) nanoarray electrode is designed by a facile hot bath method for Na storage. This interesting electrode exhibits areal reversible capacity of ca. 3.7 mAh cm (900 mAh g) and rate capability of 1.6 mAh cm (400 mAh g) at 40 mA cm (10 A g). Improved extrinsic pseudocapacitive contribution is demonstrated as the origin of fast kinetics of an alloying-based SnS electrode. Sodiation dynamics analysis based on first-principles calculations, ex-situ HRTEM, in situ impedance, and in situ Raman technologies verify the S-edge effect on the fast Na migration and reversible and sensitive structure evolution during high-rate charge/discharge. The excellent alloying-based pseudocapacitance and unsaturated edge effect enabled by self-branched surface nanoengineering could be a promising strategy for promoting development of SIBs with both high capacity and high rate response.

Encapsulation of CoSx Nanocrystals into N/S Co‐Doped Honeycomb‐Like 3D Porous Carbon for High‐Performance Lithium Storage

“…Figure 6d summarizes the percentage of the capacitive contribution of CS@PC composites at different scan rates. With the increase of the scan rate, the diffusion contribution is depressed, while the capacitive contribution is increased as expected 60. The high surface area, good 3D conductive network, and abundant active sites make the CS@PC composite with a rather high capacitive contribution, which means that it can withstand the impact of higher density currents, resulting in the CS@PC composite with a superior rate performance 63…”

“…The value of b varies from 0.5 (diffusion‐controlled process) to 1.0 (capacitive‐controlled process) and is calculated by the slope of log ( I ) versus log ( v ) plot (Figure 6b) 59. And the b values for peaks 1 and 2 are 0.72 and 0.74, respectively, indicating surface capacitive‐controlled process kinetically favored the CS@PC electrode 60, 61. According to Equation (3), by plotting I ( V )/ v 1/2 versus v 1/2 at different potentials, one can calculate the values of k 1 (slope) and k 2 (intercept) from the straight lines.…”

Hierarchical Engineering of Porous P2‐Na2/3Ni1/3Mn2/3O2 Nanofibers Assembled by Nanoparticles Enables Superior Sodium‐Ion Storage Cathodes

“…[23,60] Figure 4f shows the representative CV profile at 0.2 mV s −1 , illustrating a 29.6% pseudo-capacitance contribution (orange area) to the total current. [23,60] Figure 4f shows the representative CV profile at 0.2 mV s −1 , illustrating a 29.6% pseudo-capacitance contribution (orange area) to the total current.…”

Reduced Graphene Oxide Decorated Na3V2(PO4)3 Microspheres as Cathode Material With Advanced Sodium Storage Performance

“…Furthermore, sodium resource is abundant on earth and the price is cheap. Thus, SIBs are considered as the most promising competitive alternative to LIBs (Jian et al, 2014; Wang H. et al, 2015; Chao et al, 2016; Xu et al, 2016). Developing SIBs with excellent electrochemical performance becomes necessary and challenging.…”