High Capacity Adsorption—Dominated Potassium and Sodium Ion Storage in Activated Crumpled Graphene

Abstract

Structurally and chemically defective activated‐crumbled graphene (A‐CG) is employed to achieve unique synergy of large reversible potassium (K) and sodium (Na) ion storage capacity with fast charging and extended cyclability. A‐CG synthesis consists of low temperature spraying of graphene oxide slurry, followed by partial reduction annealing and air activation. For K storage, the reversible capacities are 340 mAh g−1 at 0.04 A g−1, 261 mAh g−1 at 0.5 A g−1, and 210 mAh g−1 at 2 A g−1. For Na storage, the reversible capacities are 280 mAh g−1 at 0.04 A g−1, 191 mAh g−1 at 0.5 A g−1, and 151 mAh g−1 at 2 A g−1. A‐CG shows a stable intermediate rate (0.5 Ag−1) cycling with both K and Na, with minimal fade after 2800 and 8000 cycles. These are among the most favorable capacity—rate capability—cyclability combinations recorded for potassium‐ion battery and sodium‐ion battery carbons. Electroanalytical studies (cyclic voltammetry, galvanostatic intermittent titration technique, b‐value) and density functional theory (DFT) reveal that enhanced electrochemical performance originates from ion adsorption at various defects, such as Stone–Wales defects. Moreover, DFT highlights enhanced thermodynamic stability of A‐CG with adsorbed K versus with adsorbed Na, explaining the unexpected higher reversible capacity with the former.

Pseudo‐Bonding and Electric‐Field Harmony for Li‐Rich Mn‐Based Oxide Cathode

“…[57] More importantly, the Li + shuttling is also accelerated during the charge process because of its capability to build a stabilized interface to alleviate SR and also enhance the ionic and electronic conductivity of the electrode materials. [58] Based on the aforementioned results, the linkage-functionalized modification successfully enhances the kinetics of Li + diffusion by increasing the diffusion coefficient, and the SR is effectively suppressed resulting in a more stable electrode/electrolyte interface. Therefore the electrochemical performance of the modified samples can be promoted, especially the 3%LCO which owns the best performance.…”

Carbon Anode Materials: A Detailed Comparison between Na‐ion and K‐ion Batteries

“…[95] Some graphene-based anode materials are simultaneously investigated in both SIBs and PIBs. Lee and co-workers [24] reported activated-crumbled graphene (A-CG) for achieving large reversible Na + /K + storage capacity. The reversible capacities at different current densities were obtained for PIBs, which were 340 at 40, 261 at 500, and 210 mAh g −1 at 2000 mA g −1 .…”

“…However, limited lithium reserve and uneven lithium graphene) provide abundant Na + /K + adsorption sites, the capacity of which is even beyond the theoretical capacity of graphite, and sloping curves are obtained during charge/discharge process. [24] Although hard carbon can deliver considerable capacity for both Na + (mainly more than 300 mAh g −1 ) and K + (mainly more than 250 mAh g −1 ), there are also obvious differences that hard carbon mainly delivers higher Na + storage capacity and lower sodiation potential. [19,[25][26][27][28][29][30] Soft carbon is also a potential SIBs/PIBs anode, and its microstructure and component (graphitization degree and heteroatom doping) directly affect Na + /K + storage behaviors.…”

Rational Design of Sb@C@TiO2 Triple‐Shell Nanoboxes for High‐Performance Sodium‐Ion Batteries

“…[2,3] Although SIBs share a similar chemical storage mechanism with lithium-ion batteries (LIBs), finding suitable electrode materials that can effectively host Na + ions, which are larger than Li + ions, and are stable during cycling remains a considerable challenge. [4] Over the past decade, extensive efforts have been devoted to developing appropriate anode materials with a high rate capability and good cycling stability for SIBs, such as carbonaceous materials, [5][6][7] conversion-type materials (e.g., metal oxides, [8] chalcogenides, [9][10][11][12][13] and phosphides [14,15] ), intercalation compounds, [16][17][18][19][20][21] and alloy-type materials (e.g., Sb, [22][23][24][25][26][27][28] Bi, [29][30][31][32] P, [33][34][35] and Sn [36,37] ). Among them, metallic Sb is regarded as one of the most promising anode materials for SIBs because of its high theoretical capacity of around 660 mAh g −1 (corresponding to Na 3 Sb) and appropriate redox potential (0.5-0.8 V vs Na/Na + ).…”