Dual‐Sites Coordination Engineering of Single Atom Catalysts for Full‐Temperature Adaptive Flexible Ultralong‐Life Solid‐State Zn−Air Batteries

Abstract

High‐performance rechargeable Zn‐air batteries with long‐life stability are desirable for power applications in electric vehicles. The key component of the Zn‐air batteries is the bifunctional oxygen electrocatalyst, however, designing a bifunctional oxygen electrocatalyst with high intrinsic reversibility and durability is a challenge. Through density functional theory calculations, it is found that the catalytic activity originated from the electronic and geometric coordination structures synergistic effect of the Fe and Co dual‐sites with metal‐N4 coordination environment, assisting the stronger hybridization of electronic orbitals between Co (dxz, dz2) and OO* (px, pz), thus making the stronger O2 active ability of Co active site. These findings enable to development of a fancy dual single‐atom catalyst comprising adjacent FeN4 and CoN4 sites on N‐doped carbon matrix (FeCo‐NC). FeCo‐NC exhibits extraordinary bifunctional activities for oxygen reduction and evolution reaction (ORR/OER), which displays high half‐wave potential (0.893 V) for the ORR, and low overpotential (343 mV) at 10 mA cm−2 for the OER. The assembled FeCo‐NC air‐electrode works well in the flexible solid‐state Zn‐air battery with a high specific capacity of 747.0 mAh g−1, a long‐time stability of more than 400 h (30 °C), and also a superior performance at extreme temperatures (−30 °C–60 °C).

Geometric and Electronic Engineering of Atomically Dispersed Copper‐Cobalt Diatomic Sites for Synergistic Promotion of Bifunctional Oxygen Electrocatalysis in Zinc–Air Batteries

“…Raman spectrum of Cu‐Co/NC (Figure S12, Supporting Information) shows an I D / I G ratio of 1.28, confirming a more defective structure of the NC matrix, which facilitates the adsorption of oxygen intermediates during the ORR and OER reactions. [ 30 ] Moreover, the porous structure of Cu‐Co/NC was verified by N 2 adsorption/desorption measurements (Figure S13, Table S3, Supporting Information). The larger specific surface area and high porosity of Cu‐Co/NC are beneficial for promoting the exposure of metal sites and mass transfer during the reactions.…”

“…[16,[25][26][27][28][29] Another effective approach is to construct SAs with two different transition metals through the synergetic effect of dual-metal sites to modulate the electrocatalysts' activity. [30][31][32][33][34][35][36][37][38] Such an approach takes advantage of the two isolated metal sites by pairing or long-range coupling to modulate the coordination and electronic structures, which correlates with the adsorption/desorption behavior of relevant oxygen intermediates. [39][40][41][42][43] However, a comprehensive study of the synergetic effect of isolated dual-metal sites has not been explored in most studies.…”

Electrochemical synthesis of ammonia from nitric oxide in a membrane electrode assembly electrolyzer over a dual Fe–Ni single atom catalyst

“…The presence of Fe 2p 3/2 and Ni 2p 3/2 characteristic peaks reveals the existence of Ni-N and Fe-N coordination. 45,46 The high-resolution N 1s spectrum is deconvoluted to four binding energy shis such as 398.8, 400.9, 402.5, and 405.1 eV, corresponding to pyridinic-N, pyrrolic-N, graphitic-N, and oxidized-N contents, respectively (Fig. 3d).…”

Cooperation between Dual Metal Atoms and Nanoclusters Enhances Activity and Stability for Oxygen Reduction and Evolution

“…And their oxygen evolution reaction (OER) performance especially the long-run stability is also unsatisfactory. According to recent experimental/theoretical studies, rationally tailoring the central metal atom by introducing a secondary metal core (e.g., dual atom catalysts) and alternative coordination environment, such as ionic dopants, is an efficient approach to modulate the electronic configuration of the metal active sites to achieve suitable binding strength for oxygen-containing intermediates, thereby reducing the reaction energy barriers and boosting their catalytic activities. − For example, Yang et al showed that the adjacent Mn–N moieties in Fe–N–C catalysts can cause Fe III electron delocalization and convert the spin state of Fe III from low to intermediate spin state, the latter of which can penetrate the antibonding π-orbital of oxygen, leading to enhanced ORR activity. , Tong et al developed a bimetallic single-atom catalyst consisting of CuN 4 and ZnN 4 sites. In this dual configuration, the low-electronegativity Zn atom donates an electron to Cu atoms and adjusts the d electron configuration of copper, ultimately benefiting the elongation and cleavage of O–O on the Cu active site and accelerating the ORR kinetics .…”