This review provides an up-to-date summary of the progress of organic quinones as electroactive materials for advanced electrochemical energy storage devices.

TE material research has attracted intense interest over the past few decades. [1] The TE performance of a material is measured by zT = σS 2 T/κ, where T, σ, S, and κ are the absolute temperature, electrical conductivity, Seebeck coefficient, and total thermal conductivity, respectively. Typically, κ = κ el + κ ph , where the κ el and κ ph are the carrier and lattice thermal conductivity, respectively. Since σ, S, and κ el are adversely interrelated whereas the κ ph is relatively independent of σ, S, and κ el , the stride toward high zT is in line with a two-pronged strategy, coined by Slack as "electron-crystal phonon-glass" (ECPG): [2] i) decoupling σ, S, and κ el through band structure engineering toward a high power factor (PF) = σS 2 ; [3,4] and ii) suppressing the κ ph via all-scale hierarchical microstructures. [5][6][7] Rooted in the core effects of high entropy alloys (HEAs), entropy engineering enables a synergy of band structure engineering and multiscale hierarchical microstructures through high entropy alloying. HEAs typically refer to the solid solutions in which more than five principal elements each in 5-35% molar ratio compete for the same crystallographic site, yielding high entropy of mixing and a wider variety of exciting properties. [8] HEA is a subset of multielement-doped materials. Neither the doping process nor the resulting composition would differentiate aThe core effects of high entropy alloys distinguish high entropy alloying from ordinary multielement doping, allowing for a synergy of band structure and microstructure engineering. Here, a systematic synthesis, structural, theoretical, and thermoelectric study of multi-principal-element-alloyed SnTe is reported. Toward high thermoelectric performance, the entropy of mixing needs to be high enough to make good use of the core effects, yet low enough to minimize the degradation of carrier mobility. It is demonstrated that high entropy of mixing extends the solubility limit of Mn while retaining the lattice symmetry, the enhanced Mn content elicits multiscale microstructures. The resulting ultralow lattice thermal conductivity of ≈0.32 W m −1 K −1 at 900 K in (Sn 0.7 Ge 0.2 Pb 0.1 ) 0.75 Mn 0.275 Te is not only lower than the amorphous limit of SnTe but also comparable to those thermoelectric materials with complex crystal structures and strong anharmonicity. Co-alloying of (Sn,Ge,Pb,Mn) also enhances band convergence and band effective mass, yielding good power factors. Further tuning of the Sn excess yields a state-of-the-art zT ≈1.42 at 900 K in (Sn 0.74 Ge 0.2 Pb 0.1 ) 0.75 Mn 0.275 Te. In view of the simple face-centeredcubic structure of SnTe-based alloys, these results attest to the efficacy of entropy engineering toward a new paradigm of high entropy thermoelecrics.

Low-temperature additive manufacturing (AM) holds promise for fabrication of three-dimensional (3D) scaffolds containing bioactive molecules and/or drugs. Due to the strict technical limitations of current approaches, few materials are suitable for printing at low temperature. Here, a low-temperature robocasting method was employed to print biomimic 3D scaffolds for bone regeneration using a routine collagen-hydroxyapatite (CHA) composite material, which is too viscous to be printed via normal 3D printing methods at low temperature. The CHA scaffolds had excellent 3D structure and maintained most raw material properties after printing. Compared to nonprinted scaffolds, printed scaffolds promoted bone marrow stromal cell proliferation and improved osteogenic outcome in vitro. In a rabbit femoral condyle defect model, the interconnecting pores within the printed scaffolds facilitated cell penetration and mineralization before the scaffolds degraded and enhanced repair, compared to nonprinted CHA scaffolds. Additionally, the optimal printing parameters for 3D CHA scaffolds were investigated; 600-μm-diameter rods were optimal in terms of moderate mechanical strength and better repair outcome in vivo. This low-temperature robocasting method could enable a variety of bioactive molecules to be incorporated into printed CHA materials and provides a method of bioprinting biomaterials without compromising their natural properties.