Defect‐Selectivity and “Order‐in‐Disorder” Engineering in Carbon for Durable and Fast Potassium Storage

Abstract

Defect‐rich carbon materials possess high gravimetric potassium storage capability due to the abundance of active sites, but their cyclic stability is limited because of the low reversibility of undesirable defects and the deteriorative conductivity. Herein, in situ defect‐selectivity and order‐in‐disorder synergetic engineering in carbon via a self‐template strategy is reported to boost the K+‐storage capacity, rate capability and cyclic stability simultaneously. The defect‐sites are selectively tuned to realize abundant reversible carbon‐vacancies with the sacrifice of poorly reversible heteroatom‐defects through the persistent gas release during pyrolysis. Meanwhile, nanobubbles generated during the pyrolysis serve as self‐templates to induce the surface atom rearrangement, thus in situ embedding nanographitic networks in the defective domains without serious phase separation, which greatly enhances the intrinsic conductivity. The synergetic structure ensures high concentration of reversible carbon‐vacancies and fast charge‐transfer kinetics simultaneously, leading to high reversible capacity (425 mAh g−1 at 0.05 A g−1), high‐rate (237.4 mAh g−1 at 1 A g−1), and superior cyclic stability (90.4% capacity retention from cycle 10 to 400 at 0.1 A g−1). This work provides a rational and facile strategy to realize the tradeoff between defect‐sites and intrinsic conductivity, and gives deep insights into the mechanism of reversible potassium storage.

Multifunctional sulfate-assistant synthesis of seaweed-like N,S-doped carbons as high-performance anodes for K-ion capacitors

“…In addition, C–S–C also exhibited better reversibility than C–SO x –C. 54 The above results also confirm that the NSPC700 anode delivered a higher reversible capacity due to its rich N and S heteroatoms in the specific formations (N-5, N-Q, and C–S–C).…”

“…It is shown that C-S-C was almost transformed into -K 2 S x , while only a part of C-SO x -C was combined with K ions aer potassiation (Table S3 †). In addition, C-S-C also exhibited better reversibility than C-SO x -C. 54 The above results also conrm that the NSPC700 anode delivered a higher reversible capacity due to its rich N and S heteroatoms in the specic formations (N-5, N-Q, and C-S-C).…”

Oxygenated P/N co-doped carbon for efficient 2e−oxygen reduction to H2O2

“…The main reason for the high number of defects is that a lot of heteroatom dopants are lost during high-temperature pyrolysis. 45 All the samples exhibit type-IV N 2 adsorption–desorption isotherms with a strip hysteresis loop over a wide relative pressure range (Fig. 1H).…”

Bitumen‐Derived Onion‐Like Soft Carbon as High‐Performance Potassium‐Ion Battery Anode

“…Compared with the recent studies on carbon-based PIBs anodes (Figure 2j), the OLSC exhibits an excellent rate performance and stability while ensuring a lower voltage plateau. [11,27,[37][38][39][40][41] The full-cell tests of OLSC further proved the practical application of OLSC in potassium-ion batteries. As shown in Figure S7 (Supporting Information), the K 2 MnFe(CN) 6 ||OLSC full cell showed a suitable voltage plateau about 1.5 V, and a discharge capacity of 78.6 mAh g -1 after 100 cycles.…”