Boosting the potassium-ion storage performance of a carbon anode by chemically regulating oxygen-containing species

Abstract

The oxygen-containing species in melamine foam carbons are chemically regulated. The optimized carbon anode shows an enhanced potassium-ion storage performance in terms of reversible capacity, rate capability, and long-term cycling stability.

Defects in Hard Carbon: Where Are They Located and How Does the Location Affect Alkaline Metal Storage?

“…From experimental evidence, oxygen heteroatoms are beneficial for improving the wettability of HC, and oxygen defects can enhance metal adsorption. [ 1,7,39,62–65 ]…”

“…Oxygen-containing defects are prevalent in HC anodes, and can play an important role in increasing the surface wettability, which in turn improves the battery stability and performance. [1,7,15,36,39,[62][63][64][65] Tuning the oxygen defect concentration and position (surface vs bulk) allows for physicochemical properties to be optimized. [1,62,64] Experimental XPS measurements commonly identify an oxygen content of ≈4% in HC, soft carbon, and composite carbon anodes for LIBs, NIBs, and KIBs.…”

“…From experimental evidence, oxygen heteroatoms are beneficial for improving the wettability of HC, and oxygen defects can enhance metal adsorption. [1,7,39,[62][63][64][65] In the bulk-like regime, the O C defects sit at a three coordinated C-lattice site (Figures 5a and 6a, positions 1-9, and Figure S13 (Supporting Information)). As the surface is approached, the CO bond perpendicular to the surface breaks (Figure 6a), leaving a C-dangling bond.…”

Aerosol-Assisted Assembly of Mesoporous Carbon Spheres With Fast and Stable K-ion Storage

“…Potassium locates within the same group in the periodic table with lithium, which exhibits similar chemical properties with the Li element. As a new energy storage device, potassium ion batteries show great potential for large scale application because of the abundant reserves of potassium resources in the earth's crust as well as a lower redox potential of K/K + (−2.93 V vs. SHE) compared with Na/Na + (−2.71 V), thus a wider potential window and higher energy density could be achieved (Le et al, 2017 ; Wu et al, 2017 ; Jiang et al, 2019 ; Li L. et al, 2019 ; Liu et al, 2019a ; Zhang R. et al, 2019 ; Hosaka et al, 2020 ). Unfortunately, the relatively large radius of K + (1.38 vs. 0.76 Å of Li + ) leads to sluggish kinetics and poor cycling performance for most electrode materials in KIBs.…”

“…Currently, various electrode materials such as carbon materials (Hu et al, 2020 ; Liu M. et al, 2020 ; Zhang et al, 2020 ), alloys (Zhang et al, 2017 ; Lei et al, 2018 ; Zheng et al, 2019 ), metal oxide/sulfides (Li et al, 2020a ; Liu Y. et al, 2020 ; Zhou et al, 2020 ), titanium based insertion materials (Sultana et al, 2016 ; Dong et al, 2018 ), and MXene (Okubo et al, 2018 ; Tang et al, 2020 ; Zhao et al, 2020 ) have been extensively studied as promising anodes for K-ion storage. Benefiting from the abundant resources, low cost, allotrope, and excellent physical/chemical stability, carbon materials have been widely reported and used for KIBs (Jian et al, 2015 ; Liu et al, 2019b ; Zhang R. et al, 2019 ; Huang et al, 2020 ; Li et al, 2020b ). The application of carbon based material for potassium ion storage requires high conductivity and large interlayer space for large K + insertion.…”