Amine-Wetting-Enabled Dendrite-Free Potassium Metal Anode

Abstract

Considered as an imperative alternative to the commercial LiFePO4 battery, the potassium metal battery possesses great potential in grid-scale energy storage systems due to the low cost, low standard redox potential, and high abundance of potassium. The potassium dendrite growth, large volume change, and unstable solid electrolyte interphase (SEI) on the potassium metal anode have, however, hindered its applications. Although conductive scaffolds coupling with potassium metal have been widely proposed to address the above issues, it remains challenging to fabricate a uniform composite with uncompromised capacity. Herein, we propose a facile and efficient strategy to construct dendrite-free and practical carbon-based potassium composite anodes via amine functionalization of the carbon scaffolds that enables fast molten potassium infusion within several seconds. On the basis of experiments and theoretical calculations, we show that highly potassiophilic amine groups immediately transform carbon scaffolds from nonwetting to wetting to postassium. Our carbon-cloth-based potassium composite anode (K@CC) can accommodate volume fluctuation, provide abundant nucleation sites, and lower the local current density, achieving nondendritic morphology with a stable SEI. The fabricated K0.7Mn0.7Ni0.3O2|K@CC full cell displays excellent rate capability and an ultralong lifespan over 8000 cycles (68.5% retention) at a high current of 1 A g–1.

Homogeneous Metallic Deposition Regulated by Porous Framework and Selenization Interphase Toward Stable Sodium/Potassium Anodes

“…Herein, the discharge depth of K in this composite anode is ≈5.5% via the corresponding capacity ratio calculation. Additionally, the cycle lifespan of our composite K anode is better than that of other reported 3D composite K anodes in carbonated electrolyte (Figure 7b; Table S2, Supporting Information), such as K/CP, [ 51 ] K/rGO@Cu, [ 45 ] K‐ACM, [ 57 ] PM/NiO/K, [ 58 ] CC/SnO 2 @K, [ 48 ] K@Mxene‐CNT, [ 59 ] K/N‐CC, [ 60 ] and K/Cu 3 Pt. [ 61 ] The rate performances of K 2 Se/Cu@K and bare K symmetrical cells are demonstrated in Figure S26 (Supporting Information), in which the K 2 Se/Cu@K composite anode presents a lower polarized voltage compared with bare K anode at the current density ranging from 0.5 to 5 mA cm −2 .…”

Engineering current collectors for advanced alkali metal anodes: A review and perspective

“…The defect‐rich aromatic structure formed a resilient, F‐rich SEI layer for Na homogenously depositing throughout the entire host structure. Qiao and co‐workers revealed that highly potassiophilic amine groups significantly enhance the wettability of potassium to carbon scaffolds, which increases nucleation sites, decreases the local current density, and facilitates nondendritic Na deposition 166 …”

“…Qiao and coworkers revealed that highly potassiophilic amine groups significantly enhance the wettability of potassium to carbon scaffolds, which increases nucleation sites, decreases the local current density, and facilitates nondendritic Na deposition. 166 Since the discovery of MXenes in 2011, they have been widely used in alkali metal batteries to make use of their adjustable electronic structure and physicochemical properties. The wide layer spacing of MXenes could be embedded with ions of large sizes, such as Na + and K + , and ensure low migration resistances.…”

Low‐Temperature High‐Areal‐Capacity Rechargeable Potassium‐Metal Batteries

“…Notably, potassium ions (K + ) possess a smaller Stokes radius compared to lithium/sodium ions due to their weaker Lewis acidity, which endow K + electrolytes with high ionic conductivity and fast ion diffusion. [ 24,25 ] Also, the weak K + ‐solvent interactions enable low desolvation energy, which would boost the kinetics of charge‐transfer processes. [ 26 ] Besides, K metal possesses high theoretical specific capacity (687 mAh g −1 ), low redox potential (−2.93 V vs standard hydrogen electrode), and high natural abundance (1.5 wt%).…”