Ultra-Low-Dose Pre-Metallation Strategy Served for Commercial Metal-Ion Capacitors

Abstract

Highlights Interfacial bonding strategy has been successfully applied to address the high overpotential issue of sacrificial additives, which reduced the decompositon potential of Na2C2O4 from 4.50 to 3.95 V. Ultra-low-dose technique assisted commercial sodium ion capacitor (AC//HC) could deliver a remarkable energy density of 118.2 Wh kg−1 as well as excellent cycle stability. In-depth decomposition mechanism of sacrificial compound and the relative influence after pre-metallation were revealed by advanced in situ and ex situ characterization approaches. Abstract Sacrificial pre-metallation strategy could compensate for the irreversible consumption of metal ions and reduce the potential of anode, thereby elevating the cycle performance as well as open-circuit voltage for full metal ion capacitors (MICs). However, suffered from massive-dosage abuse, exorbitant decomposition potential, and side effects of decomposition residue, the wide application of sacrificial approach was restricted. Herein, assisted with density functional theory calculations, strongly coupled interface (M–O–C, M = Li/Na/K) and electron donating group have been put forward to regulate the band gap and highest occupied molecular orbital level of metal oxalate (M2C2O4), reducing polarization phenomenon and Gibbs free energy required for decomposition, which eventually decrease the practical decomposition potential from 4.50 to 3.95 V. Remarkably, full sodium ion capacitors constituted of commercial materials (activated carbon//hard carbon) could deliver a prominent energy density of 118.2 Wh kg−1 as well as excellent cycle stability under an ultra-low dosage pre-sodiation reagent of 15–30 wt% (far less than currently 100 wt%). Noteworthily, decomposition mechanism of sacrificial compound and the relative influence on the system of MICs after pre-metallation were initially revealed by in situ differential electrochemical mass spectrometry, offering in-depth insights for comprehending the function of cathode additives. In addition, this breakthrough has been successfully utilized in high performance lithium/potassium ion capacitors with Li2C2O4/K2C2O4 as pre-metallation reagent, which will convincingly promote the commercialization of MICs.

Natural Stibnite for Lithium-/Sodium-Ion Batteries: Carbon Dots Evoked High Initial Coulombic Efficiency

“…In order to tackle these key problems, multifarious ways have been proposed, such as combining with highly conductive carbonaceous materials [ 4 , 5 ], designing greatly stable structures [ 6 , 7 ], building interfacial bonds [ 8 ], and introducing doping heteroatoms [ 9 ]. Constructing Sb 2 S 3 /carbon composite is the most common and effective strategy [ 10 – 12 ]. For instance, Sb 2 S 3 /sulfur-doped graphene sheets composite prepared by Liu et al showed a high-capacity retention of 83% for 900 cycles at 2 A g −1 [ 13 ].…”

Strongly Coupled Interfacial Engineering Inspired by Robotic Arms Enable High‐Performance Sodium‐Ion Capacitors

“…It is worth noting that ameliorated Na 2 C 2 O 4 reported in our previous work is adopted as sacrificial © 2022 Wiley-VCH GmbH cathode additive to accomplish the mission of pre-sodiation as it can be identified as optimal candidate for scale-up production. [28] Interestingly, the pouch-type capacitors can deliver a remarkable energy density of 73.6 Wh kg -1 at the current density of 0.1 A g -1 (Figure S12b, Supporting Information) after activation within the voltage window of 4.3-0 V (Figure S12c, Supporting Information), delivering great application potential.…”

Reversible Oxygen-Rich Functional Groups Grafted 3D Honeycomb-Like Carbon Anode for Super-Long Potassium Ion Batteries

“…Nevertheless, the sluggish diffusion kinetics of K + and the degradation of the structure due to the large radius of potassium (0.138 nm) hinder the development of anode electrodes of PIBs [5][6][7][8][9]. Carbon-based materials have acted as an important role in the construction of anode electrode engineering since it was reported that K + can be de/inserted into graphite in 2015 [10][11][12][13][14]. However, the rate performance and cycle stability of graphite as an anode are unsatisfactory due to the limited layer spacing and polarization phenomenon.…”