Constructing Active BN Sites in Carbon Nanosheets for High‐Capacity and Fast Charging Toward Potassium Ion Storage

Abstract

Nitrogen doping is an effective strategy to improve potassium ion storage of carbon electrodes via the creation of adsorption sites. However, various undesired defects are often uncontrollably generated during the doping process, limiting doping effect on capacity enhancement and deteriorating the electric conductivity. Herein, boron element is additionally introduced to construct 3D interconnected B, N co‐doped carbon nanosheets to remedy these adverse effects. This work demonstrates that boron incorporation preferentially converts pyrrolic N species into BN sites with lower adsorption energy barrier, further enhancing the capacity of B, N co‐doped carbon. Meanwhile, the electric conductivity is modulated via the conjugation effect between the electron‐rich N and electron‐deficient B, accelerating the charge‐transfer kinetics of potassium ions. The optimized samples deliver a high specific capacity, high rate capability, and long‐term cyclic stability (532.1 mAh g−1 at 0.05 A g−1, 162.6 mAh g−1 at 2 A g−1 over 8000 cycles). Furthermore, hybrid capacitors using the B, N co‐doped carbon anode deliver a high energy and power density with excellent cycle life. This study demonstrates a promising approach using BN sites for adsorptive capacity and electric conductivity enhancement in carbon materials for electrochemical energy storage applications.

An ecofriendly and universal strategy to balance the active sites and electrical conductivity of biomass-derived carbon for superior lithium storage

“…where k 1 v and k 2 v 1/2 correspond to the diffusion current and pseudo-capacitive current, respectively. 45,46 For instance, the calculated capacitance contribution of the BO-CNS is about 74.75% at a scan rate of 1.0 mV s À1 , which is much higher than that of the O-CNS (56.38%) as shown in Fig. 6c and f.…”

Tailoring B, N-Enriched Carbon Nanosheets via a Gelation-Assisted Strategy for High-Capacity and Fast-Response Capacitive Desalination

“…In detail, the narrow scan of BNCTs C 1s spectrum can be deconvoluted into C–B, CC, CO/CN, CO/C–N–B, and –COOR, respectively, illustrating the successful incorporation of B and N in BNCTs . In the N 1s spectrum in Figures e and S10a, four characteristic peaks were observed centered at ∼397.7, 398.4, 399.2, and 400.7 eV, which are corresponding to the functional groups of B–N, pyridinic N, pyrrolic N, and graphitic N, respectively. , What distinguishes from the NC sample in Figure S11 is the appearance of B–N bonds with intensive adsorption to multiple alkali metal ions in B, N dual-doped carbon. The B 1s spectra can be fitted with 191.1, 190.6, 191.3, and 192.0 eV, which corresponds to C 3 –B, C 2 –BO, B–N, and C–BO 2 , respectively (Figures f and S10b).…”

“…39 In the N 1s spectrum in Figures 3e and S10a, four characteristic peaks were observed centered at ∼397.7, 398.4, 399.2, and 400.7 eV, which are corresponding to the functional groups of B−N, pyridinic N, pyrrolic N, and graphitic N, respectively. 27,40 What distinguishes from the NC sample in Figure S11 is the appearance of B−N bonds with intensive adsorption to multiple alkali metal ions in B, N dual-doped carbon. The B 1s spectra can be fitted with 191.…”

Architecting carbon-coated Mo2CTx/MoSe2 heterostructures enables robust potassium storage

“…The strong peaks located at 817 and 989 cm À1 could be related to Mo 2 CT x . 12 Additionally, the strong peaks located at 1344 and 1579 cm À1 could be ascribed to the disorder-band and graphitic-band of carbon, respectively, with an intensity ratio of 1.39 (I D /I G ), confirming the presence of disordered carbon in the hybrid structure. A high degree of carbon disorder and defects could supply additional active sites for the accumulation of K + .…”