Three-Dimensional Cobalt Hydroxide Hollow Cube/Vertical Nanosheets with High Desalination Capacity and Long-Term Performance Stability in Capacitive Deionization

Abstract

Faradaic electrode materials have significantly improved the performance of membrane capacitive deionization, which offers an opportunity to produce freshwater from seawater or brackish water in an energy-efficient way. However, Faradaic materials hold the drawbacks of slow desalination rate due to the intrinsic low ion diffusion kinetics and inferior stability arising from the volume expansion during ion intercalation, impeding the engineering application of capacitive deionization. Herein, a pseudocapacitive material with hollow architecture was prepared via template-etching method, namely, cuboid cobalt hydroxide, with fast desalination rate (3.3 mg (NaCl)·g-1 (h-Co(OH)2)·min-1 at 100 mA·g-1) and outstanding stability (90% capacity retention after 100 cycles). The hollow structure enables swift ion transport inside the material and keeps the electrode intact by alleviating the stress induced from volume expansion during the ion capture process, which is corroborated well by in situ electrochemical dilatometry and finite element simulation. Additionally, benefiting from the elimination of unreacted bulk material and vertical cobalt hydroxide nanosheets on the exterior surface, the synthesized material provides a high desalination capacity (117±6 mg (NaCl)·g-1 (h-Co(OH)2) at 30 mA·g-1). This work provides a new strategy, constructing microscale hollow faradic configuration, to further boost the desalination performance of Faradaic materials.

Ti3C2‐MXene Partially Derived Hierarchical 1D/2D TiO2/Ti3C2 Heterostructure Electrode for High‐Performance Capacitive Deionization

“…The capacitance slightly increased after a long cycle, which might be attributed to the contact between the TiO 2 nanowires and Ti 3 C 2 nanosheets becoming tighter due to the electroactivation effect during the ion deintercalation cycle, further improving the electrochemical performance of TiO 2 /Ti 3 C 2 . [ 34 ] Figure 3c compares the CV curves of TiO 2 /Ti 3 C 2 and the initial Ti 3 C 2 at 50 mV s −1 , and the specific capacitances under different specific currents are displayed in Figure 3d . The specific capacitance of TiO 2 /Ti 3 C 2 was 207 F g −1 at 10 mV s −1 , while that of Ti 3 C 2 was only 63 F g −1 .…”

“…[31] The N 2 adsorption-desorption isotherms of the TiO 2 /Ti 3 C 2 hybrids displayed a representative type-IV curve with an H3-type hysteresis loop (Figure 2d), indicating the predominant mesoporous structures of the compounds and showing a slit pore geometry due to the stacking of spark particles. [32] The SSA of TiO 2 /Ti 3 C 2 (50.74 m 2 g −1 ) was much larger than that of the pristine MXene nanosheets (S BET = 17.56 m 2 g −1 ) due to the growth of TiO 2 nanowires on the interlayer increasing the interlayer space of Ti 3 C 2 . Figure 2e displays the pore size distributions of Ti 3 C 2 and TiO 2 /Ti 3 C 2 , indicating that more mesopores appeared in the TiO 2 /Ti 3 C 2 structure, which was due to the construction of the 1D/2D hierarchical structure.…”

Graphene-assisted Ti3C2 MXene-derived ultrathin sodium titanate for capacitive deionization with excellent rate performance and long cycling stability

“…This result also proved that the desalination mechanism of M-NTO/rGO is pseudo-capacitance rather than the double electric layer mechanism. 30,31…”

“…This result also proved that the desalination mechanism of M-NTO/rGO is pseudo-capacitance rather than the double electric layer mechanism. 30,31 On the one hand, the hydrophilic functional groups are derived from the functional groups of the precursor MXene itself; on the other hand, the further improvement of the hydrophilicity of the material can be attributed to the high temperature and high pressure solvothermal reaction conditions, which favor the formation of more oxygen-containing functional groups on the surface of the material. 32 Fig.…”

Corrigendum to “Three-Dimensional Cobalt Hydroxide Hollow Cube/Vertical Nanosheets with High Desalination Capacity and Long-Term Performance Stability in Capacitive Deionization”

“…In the article titled “Three-Dimensional Cobalt Hydroxide Hollow Cube/Vertical Nanosheets with High Desalination Capacity and Long-Term Performance Stability in Capacitive Deionization” [ 1 ], there was an error in the title. It previously read “Three-Dimensional Cobalt Hydroxide Hollow Cube/Vertical Nanosheets with High Desalinatio Capacity and Long-Term Performance Stability”, which was incorrect.…”