The serious dissolution of organic electrode materials (e.g., perylene-3,4,9,10-tetracarboxylic dianhydride, PTCDA) in electrolytes is a major challenge, deteriorating their electrochemical performances and hindering the interpretation of the fundamental redox reaction mechanisms including the intrinsic kinetics and the solvent cointercalation.
View Article and Find Full Text PDFThe practical application of lithium metal batteries is hindered by the poor reversibility and large volume change caused by the uncontrollable dendritic growth and the highly reactive surface. In this work, favorable Li deposition is achieved by generating gradient lithiophilicity and conductivity in an Ag-decorated graphene/holey graphene film (G-HGA). Dendrite-free Li metal is deposited on the G-HGA matrix, which greatly reduces the surface area and suppresses the side reaction between the electrolyte and the dendritic Li.
View Article and Find Full Text PDFProton conduction underlies many important electrochemical technologies. A family of new proton electrolytes is reported: acid-in-clay electrolyte (AiCE) prepared by integrating fast proton carriers in a natural phyllosilicate clay network, which can be made into thin-film (tens of micrometers) fluid-impervious membranes. The chosen example systems (sepiolite-phosphoric acid) rank top among the solid proton conductors in terms of proton conductivities (15 mS cm at 25 °C, 0.
View Article and Find Full Text PDFThe lithium metal anode (LMA) instability at deep cycle with high utilization is a crucial barrier for developing lithium (Li) metal batteries, resulting in excessive Li inventory and electrolyte demand. This issue becomes more severe in capacity-type lithium-sulfur (Li-S) batteries. High-concentration or localized high-concentration electrolytes are noted as effective strategies to stabilize Li metal but usually lead to a high electrolyte density (>1.
View Article and Find Full Text PDFThe energy density presents the core competitiveness of lithium (Li)-ion batteries. In conventional Li-ion batteries, the utilization of the gravimetric/volumetric energy density at the electrode level is unsatisfactory (<84 wt% and <62 vol%, respectively) due to the existence of non-electrochemical active parts among the 3D porous electrodes, including electrolytes, binders, and carbon additives. These are regarded as indispensable and irreducible components of the electronic and ionic transport network.
View Article and Find Full Text PDFThough low-cost and environmentally friendly, Li-Mn-O cathodes suffer from low energy density. Although synthesized LiMnO-like overlithiated spinel cathode with reversible hybrid anion- and cation-redox (HACR) activities has a high initial capacity, it degrades rapidly due to oxygen loss and side-reaction-induced electrolyte decomposition. Herein, we develop a two-step heat treatment to promote local decomposition as LiMnO → 2LiMnO + LiMnO + 1/2 O↑, which releases near-surface reactive oxygen that is harmful to cycling stability.
View Article and Find Full Text PDFWhite wastes (unseparated plastics, face masks, textiles, etc.) pose a serious challenge to sustainable human development and the ecosystem and have recently been exacerbated due to the surge in plastic usage and medical wastes from COVID-19. Current recycling methods such as chemical recycling, mechanical recycling, and incineration require either pre-sorting and washing or releasing CO.
View Article and Find Full Text PDFLithium-sulfur batteries are paid much attention owing to their high specific capacity and energy density. However, their practical applications are impeded by poor electrochemical performance due to the dissolved polysulfides. The concentration of soluble polysulfides has a linear relationship with the internal heat generation.
View Article and Find Full Text PDFAlthough nanostructured materials have recently enabled a dramatic improvement of the current energy-storage units in portable electronics with enhanced functionality, it is still challenging to provide a cost-efficient solution to attain the ultrahigh energy and power densities of supercapacitors (SCs) since nearly arbitrary electrodes are limited to the thinner porous structure with de facto rather low mass loading (∼1 mg cm) because of the huge limitations of pronounced impaired ion transport in subnanometer pores in thicker compact electrodes. In this contribution, we report the fabrication of a macro/mesoporous hybrid hierarchical nanocomposite SiC/holey-graphene/holey-MnO (SiC/HG/h-MnO) with tailored porosity by knitting together the quasi-aligned single-crystalline doped 3C-SiC nanowire array and in situ surface-reduced holey graphene framework into a three-dimensional quasi-ordered structure, which enables the mass growth of ultrathin h-MnO nanosheets at approximately practical levels of mass loading. The produced synergistically favorable interconnected porous architecture allows for the highly efficient electron transfer and rapid ion transport up to interior surfaces of the network.
View Article and Find Full Text PDFLithium-metal batteries have been regarded as next-generation high-energy-density candidates beyond lithium-ion batteries. However, the lithium-morphology instabilities accompanied by continuous side reactions with electrolytes inevitably leads to dissatisfactory performances and even safety issues, where the unstable interface between lithium-metal anode and electrolytes has been regarded as the root cause. Artificial solid electrolyte interphase engineering has attracted a lot of attention to stabilize lithium-metal anodes.
View Article and Find Full Text PDFSolid-state lithium metal batteries require accommodation of electrochemically generated mechanical stress inside the lithium: this stress can be up to 1 gigapascal for an overpotential of 135 millivolts. Maintaining the mechanical and electrochemical stability of the solid structure despite physical contact with moving corrosive lithium metal is a demanding requirement. Using in situ transmission electron microscopy, we investigated the deposition and stripping of metallic lithium or sodium held within a large number of parallel hollow tubules made of a mixed ionic-electronic conductor (MIEC).
View Article and Find Full Text PDFProc Natl Acad Sci U S A
February 2018
Lithium metal has gravimetric capacity ∼10× that of graphite which incentivizes rechargeable Li metal batteries (RLMB) development. A key factor that limits practical use of RLMB is morphological instability of Li metal anode upon electrodeposition, reflected by the uncontrolled area growth of solid-electrolyte interphase that traps cyclable Li, quantified by the Coulombic inefficiency (CI). Here we show that CI decreases approximately exponentially with increasing donatable fluorine concentration of the electrolyte.
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