Energetic Cost for Being “Redox-Site-Rich” in Pseudocapacitive Energy Storage with Nickel–Aluminum Layered Double Hydroxide Materials
Makaleler > Tam Makale · 2020
Yazarlar: Xianghui Zhang, Cody B. Cockreham, Esra Yılmaz, Gengnan Li, Nan Li, Su Ha, Liangjie Fu, Jianqi Qi, Hongwu Xu, Di Wu
The Journal of Physical Chemistry Letters, Uluslararası, Wos, 2020, cilt 11, ss 3745-3753
DOI: 10.1021/acs.jpclett.0c00865
Özet
Abstract Defining the energetic landscape of pseudocapacitive materials such as transition metal layered double hydroxides (LDHs) upon redox-site enrichment is essential to harnessing their power for effective energy storage. Here, coupling acid solution calorimetry, in situ XRD, and in situ DRIFTS, we demonstrate that as the Ni/Al ratio increases, both as-made (hydrated) and dehydrated NiAl-LDH samples are less stable as evidenced by their enthalpies of formation. Moreover, the higher specific capacity at an intermediate Ni/Al ratio of 3 is enabled by effective water–LDH interactions, which energetically stabilize the excessive near-surface Ni redox sites, solvate intercalated carbonate ions, and fill the expanded vdW gap, paying for the “energetic cost” of being “redox-site-rich”. Thus, from a thermodynamic perspective, engineering molecule/solid–LDH interactions on the nanoscale with confined guest species other than water, which energetically impose stronger stabilization, may help us to achieve their specific capacitance potential.