Integrated Design from Microstructural Engineering to Binder Optimization Enabling a Practical Carbon Anode with Ultrahigh ICE and Efficient Potassium Storage

Abstract

Potassium-ion batteries (PIBs) are emerging as a powerful alternative to lithium-ion battery systems in large-scale energy storage owing to plentiful resources. Nevertheless, pursuing high-yield anode materials with high initial Coulombic efficiency (ICE) and superior rate capability is still one of the most critical challenges in practical application. Herein, an integrated electrode (PC-x) derived from a petroleum coke precursor (carbon residue rate as high as 89%) is regulated from microstructural engineering to binder optimization devoting to high ICE and efficient potassium storage. Excitingly, with a strong assist from a sodium carboxymethyl cellulose (CMC) binder, the PC-900 anode displays an ultrahigh ICE of 80.5%, one of the highest values reported for PIB carbon anodes. Simultaneously, the PC-900 anode submits a high capacity (304.3 mAh g–1), superb rate (138.2 mAh g–1 at 10C), and excellent stability. Furthermore, the full cell exhibits an outstanding rate and cycling performance (210.7 mAh g–1 at 0.5C), confirming its large-scale application prospects. The ultrahigh ICE and excellent performance are mainly attributable to the beneficial microstructures (low surface area, functional group content, and larger interlayer spacing) created by microstructural engineering. Meanwhile, binder optimization also plays a crucial role in reducing the irreversible capacity and interface impedance, further improving the ICE and rate capability. Importantly, mechanism analysis confirms two-stage K+ storage behavior: reversible adsorption at edges and defects (>0.25 V) and intercalation into crystalline layers (<0.25 V). This work provides an efficient and easily scalable electrode design strategy for future practical applications of PIBs.

Breaking Low-Strain and Deep-Potassiation Trade-Off in Alloy Anodes via Bonding Modulation for High-Performance K-Ion Batteries

“…An average potassiation potential of 3.3 V vs K/K + was measured for the PBA cathode, and the (S-BP)/G anode delivered an average depotassiation potential of 0.5 V vs K/K + (Figure d), resulting in a total output voltage of 2.85 V in the full cell; this value is higher than reported for other full-cell systems (Figures d, S20, and Table S3). ,,,,,− Rate performance test results confirmed delivered discharge capacities of 562, 558, 544, 529, 500, 479, and 462 mA h g –1 at the current densities of 0.26, 0.52, 1.3, 2.6, 5.2, 7.8, and 10.4 A g –1 (Figures d,e, and S21), respectively, where both specific capacities and current densities were calculated based on the mass of the anode. The full cell was then subjected to a long cycle of galvanostatic charge/discharge tests.…”

“…Results showed that due to the high reversible capacity, suitable working potential, and rate performance of the (S-BP)/G anode, our (S-BP)/G||PBA cell has a very commendable performance combining high energy density and fast-charging performance (212 W h kg –1 at low power, 174 W h kg –1 at power density of 1600 W kg –1 , calculated based on the total mass of the cathode and anode materials), outperforming state-of-the-art PIBs with high-energy high-power densities using other anode materials, e.g., graphite, hard carbon, and organic anodes (Figure g, Table S3). ,,,,,− These results are good proof that (S-BP)/G can be used as an optimal anode material for PIBs with high energy and power density.…”

Carbon–based Materials for Li‐ion Battery

“…[12,[105][106][107][108][109] It can be produced from pitch or tar or by pyrolysis of organic polymers such as polyvinyl chloride in a low-oxygen atmosphere. [110][111][112][113] Unlike hard carbon, soft carbon, containing a semi-graphitic structure, has highly ordered graphitic domains arranged in a turbostatic disordered manner. The disordered area in soft carbon is the high-strain region, whereas the graphitic region with higher-order crystallinity is the lowstrain region.…”

“…Generally, soft carbon exhibits a sloping potential profile similar to hard carbon but without a low voltage plateau (Figure 4b). [111,120] It has been found that the Li-ion insertion in SCs is highly dependent on the heat-treatment temperature (HTT) during the synthesis. Basically, the low-temperature heattreated SC undergoes three types of Li-ion insertion mechanisms: (a) the adsorption or partial charge transfer of Li-ions on the hexagonal surface or on unstacked carbon layers, which occurs in the potential window of 0.25 to 0.8 V (represented as Type I), (b) intercalation of Li-ions into the carbon layers during charging and discharging in the potential window of 0.0 to 0.25 V (represented as Type II), and (c) the insertion of Li-ion to the microspaces at the carbon cluster edges which occurs at very low potential (represented as Type III) (Figure 4c).…”

Recent Progress and Prospects of Pitch-based Carbon Anodes for Alkali Metal-ion (Li/Na/K) Batteries

“…[47,48] Pitch, a representative of soft carbon, is a by-product of the coking or petrochemical industry, which is mainly composed of polycyclic aromatic hydrocarbon molecules. [49][50][51] Owing to the pitch-based carbon materials (PBCMs) with low cost and high carbon yield, which are recognized to be excellent precursors for the preparation of various carbon materials in the field of energy storage, whereas the lack of a relatively comprehensive summary and understanding up to now. In this review, we have systematically investigated the research progress of PBCMs as anode used for alkali metal-ion (Li/Na/K) batteries.…”