Molecular engineering toward sustainable development of multiple-doped hierarchical porous carbons for superior zinc ion storage

Abstract

Aqueous Zn-ion hybrid supercapacitors (ZHSCs) hold great potential as next-generation energy storage devices due to their low cost, excellent rate capability, long cycling life, and high safety. Heteroatom-doped hierarchical porous carbons (HD-HPCs) with integrated high specific surface area, multiscale pores, and abundant defects have been regarded as promising cathode materials for ZHSCs. However, the in situ architecture of HD-HPCs with these multiple advantages via a sustainable and controllable method remains an arduous challenge. Herein, a novel molecular engineering strategy was proposed for the in situ construction of N/P/O-doped HD-HPCs via the direct carbonization of multiple-heteroatom-rich hypermolecules. Such a strategy has multiple advantages, including the exclusion of pore-making techniques, activation agents, templates, and complicated and hazard washing processes, demonstrating its green and sustainable properties. The highly active multiple-heteroatom-rich hypermolecular precursors contributed to the formation of abundant micro/mesopores due to the self-abscission of heteroatoms and heteroatom-contiguous carbon atoms at high carbonization temperatures. Consequently, these active structural/compositional features endowed the optimal cathodes with outstanding storage capacities of 139.2 and 88.9 mA h g −1 at 0.5 and 20 A g −1 for aqueous ZHSCs, respectively. They also delivered a superior storage performance in quasi-solid ZHSCs (QS-ZHSCs) with a high specific capacity of 111.5 mA h g −1 at 0.5 A g −1 . Superior energy/power densities and long cycling stability were also achieved for aqueous and QS-ZHSCs. The theoretical calculation confirmed the synergetic effects of multiple-atom doping on enhancing the electronic conductivity and reducing the energy barrier between Zn ions and carbon, which promote the Zn-ion adsorption capability. These findings shed fresh light on the straightforward manufacture of superior HD-HPCs for electrochemical energy storage.

Interfacial‐Catalysis‐Enabled Layered and Inorganic‐Rich SEI on Hard Carbon Anodes in Ester Electrolytes for Sodium‐Ion Batteries

“…[ 42 ] The HC‐CA‐15% anode possesses a lowest σ value among all samples, also demonstrating superior electrochemical kinetics. [ 43 ] The electrochemical kinetics of the HC‐CA‐15% anode was also evaluated based on CV curves at different scan rates, which is discussed in the Supporting Information (Figure S23).…”

Suppressed Water Reactivity by Zincophilic‐Hydrophobic Electrolyte Additive for Superior Aqueous Zn Metal Batteries

“…[1] The dendrite growth is ascribed to the inhomogeneous Zn 2+ deposition caused by the rapid yet unbalanced deposition kinetics, and the side reactions spontaneously occurred due to the high activity of Zn toward H 2 O, resulting in hydrogen evolution, [2] the corrosion of Zn metal, [3] and the formation of electrochemically inactive byproducts (e.g., Zn 4 SO 4 (OH) 6 •xH 2 O, zinc hydroxide) at the Zn/electrolyte interface. [1,4,5] Moreover, these high surface area byproducts further deteriorate the uniformity of Zn 2+ deposition due to the heterogenous interface interactions, also leading to aggravated dendrite growth, and eventually forming dead Zn. As such, these issues finally compromise the plating/stripping Coulombic efficiency (CE) of Zn anode, [6] and sensitively determine the lifespan of Zn anodes in the practical AZMBs with proper N/P ratios.…”

Dual-Functionalized Ca Enables High Sodiation Kinetics for Hard Carbon in Sodium-Ion Batteries

“…More recently, HCs with atomic Zn-doping in which zinc acetate acts as a Zn precursor also exhibit expanded graphite regions ( d 002 = 0.408 nm), contributing to a significantly improved reversible capacity . In addition, modifying the pore structure (e.g., porosity and pore size) is a potent strategy to promote sodiation kinetics since it can (1) tune the specific surface area (SSA), (2) elevate the intrinsic defect concentration that favors the adsorption behavior of Na + , and (3) serve as channels to facilitate Na + transfer . Furthermore, the plateau capacity of hard carbons can be effectively increased by a rational design of pore structure, such as closed-pore structure. − For instance, ultramicropores prepared by the molten diffusion-carbonization method can offer extra Na + storage sites and serve as ionic sieves that accelerating fast diffusion of Na + during the sodiation/desodiation process .…”