Carbon Quantum Dot Surface-Engineered VO₂Interwoven Nanowires: A Flexible Cathode Material for Lithium and Sodium Ion Batteries

Abstract

The use of electrode materials in their powdery form requires binders and conductive additives for the fabrication of the cells, which leads to unsatisfactory energy storage performance. Recently, a new strategy to design flexible, binder-, and additive-free three-dimensional electrodes with nanoscale surface engineering has been exploited in boosting the storage performance of electrode materials. In this paper, we design a new type of free-standing carbon quantum dot coated VO2 interwoven nanowires through a simple fabrication process and demonstrate its potential to be used as cathode material for lithium and sodium ion batteries. The versatile carbon quantum dots that are vastly flexible for surface engineering serve the function of protecting the nanowire surface and play an important role in the diffusion of electrons. Also, the three-dimensional carbon cloth coated with VO2 interwoven nanowires assisted in the diffusion of ions through the inner and the outer surface. With this unique architecture, the carbon quantum dot nanosurface engineered VO2 electrode exhibited capacities of 420 and 328 mAh g(-1) at current density rate of 0.3 C for lithium and sodium storage, respectively. This work serves as a milestone for the potential replacement of lithium ion batteries and next generation postbatteries.

Advanced Cathode Materials for Sodium‐Ion Batteries: What Determines Our Choices?

“…[37] For higher thermal and chemical stabilities, vanadium pentoxide (V 2 O 5 ) has been investigated as a cathode material for SIBs and supercapacitors. Early studies showed that V 2 O 5 aerogels can host reversible sodium insertion/extraction.…”

Flexible Electrodes for Sodium‐Ion Batteries: Recent Progress and Perspectives

“…Recently, various active materials, such as FeS, [43] Na 2 FeP 2 O 7 , [44] Na 2 Ti 3 O 7 , [45] MoO 3−x , [46] NiCo 2 O 4 , [47] SnS 2 , [48] VO 2 , [49] FeFe(CN) 6 , [50] and Sb 2 X 3 (X = O, S), [51] have been directly grown or coated on the surface of carbon cloth. For example, Mo et al [47] reported the growth of three-dimensional porous NiCo 2 O 4 nanowire arrays on a carbon cloth (denoted as NCO@CFC) via the solution method with a subsequent annealing treatment (Figure 2e,f).…”

“…Moreover, the flexible anode also showed improved cycling stability and rate performance compared with a NCO electrode prepared by the conventional slurry-casting method, suggesting that this flexible electrode is a promising candidate for flexible SIBs. Further, Balogun et al [49] synthesized VO 2 interwoven nanowires coated with carbon quantum dots (CQDs) grown on carbon cloth. When used as flexible cathode, it showed high sodium-storage capacity (320 mA h g −1 at 0.3C), good rate capacity (133 mA h g −1 at 60C), and high energy/power density (264 W h kg −1 /41 333 W kg −1 ), which are comparable to those for lithium-storage performance.…”

Nanostructured layered vanadium oxide as cathode for high-performance sodium-ion batteries: a perspective

“…The energy and power densities of as-fabricated cathode for Na storage reach 264 Wh/kg and 41333 W/kg [30] VO 2 /rGO nanorods 160 mA h/g at 60 mA/g…”

“…Tong and co-workers also reported an unique free-standing cathode consisted of carbon quantum dots coated VO 2 nanowires. [30] The carbon quantum dots, which are flexible for surface engineering can efficiently ensure the integrity of nanowire. Another interesting work demonstrates the facile microwave-assisted solvothermal method to fabricate VO 2 (B)/ reduced graphene oxide (rGO) with good Na storage performance.…”