Abstract
Nanosizing is the fashionable method to obtain a desirable electrode material for energy storage applications, and thus, a question arises: do smaller electrode materials exhibit better electrochemical performance? In this context, theoretical analyses on the particle size, band gap and conductivity of nano-electrode materials were performed; it was determined that a critical size exist between particle size and electrochemical performance. To verify this determination, for the first time, a scalable formation and disassociation of nickel-citrate complex approach was performed to synthesize ultra-small Ni(OH)2 nanoparticles with different average sizes (3.3, 3.7, 4.4, 6.0, 6.3, 7.9, 9.4, 10.0 and 12.2 nm). The best electrochemical performance was observed with a specific capacity of 406 C g−1, an excellent rate capability was achieved at a critical size of 7.9 nm and a rapid decrease in the specific capacity was observed when the particle size was <7.9 nm. This result is because of the quantum confinement effect, which decreased the electrical conductivity and the sluggish charge and proton transfer. The results presented here provide a new insight into the nanosize effect on the electrochemical performance to help design advanced energy storage devices.
Highlights
Electrochemical energy storage devices, such as batteries and supercapacitors, have attracted great attention because of their many advantages compared with other power-source technologies
The results presented here provide a new insight into the nanosize effect on the electrochemical performance to help design advanced energy storage devices
(where Ebulk is the bulk band gap, ΔE is related to the quantum confinement effect, me* is the effective mass of an electron, mh* is the effective mass of a hole and h is Plank’s constant), the band gap increases as the particle size reduces
Summary
Electrochemical energy storage devices, such as batteries and supercapacitors, have attracted great attention because of their many advantages compared with other power-source technologies These devices could realize further gains in energy and power densities if the electrochemical performance of electrode materials is largely improved.[1,2] Reducing the dimensions of electrode materials down to the nanoscale level is an effective strategy to promote their electrochemical performance, which primarily benefits from the nanosize effect, that is, achieving a higher surface area and a shorter ion diffusion length.[3,4] In this context, various nanosize electrode materials with greatly improved electrochemical performance have been synthesized.[5,6,7,8,9] Thereupon a fundamental question arises: do smaller electrode materials exhibit better electrochemical performance? It should be noted that the quantum confinement effect, a sort of nanosize effect, inevitably arises as the particle size reduces to the nanoscale, when o10 nm.[10,11,12] we deduced the relationships between particle size, conductivity (σ) and ΔE (Equation (2) and Equation (3))
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
