A single nanopore structure that embeds all components of an electrochemical storage device could bring about the ultimate miniaturization in energy storage. Self-alignment of electrodes within each nanopore may enable closer and more controlled spacing between electrodes than in state-of-art batteries. Such an 'all-in-one' nanopore battery array would also present an alternative to interdigitated electrode structures that employ complex three-dimensional geometries with greater spatial heterogeneity. Here, we report a battery composed of an array of nanobatteries connected in parallel, each composed of an anode, a cathode and a liquid electrolyte confined within the nanopores of anodic aluminium oxide, as an all-in-one nanosize device. Each nanoelectrode includes an outer Ru nanotube current collector and an inner nanotube of V₂O₅ storage material, forming a symmetric full nanopore storage cell with anode and cathode separated by an electrolyte region. The V₂O₅ is prelithiated at one end to serve as the anode, with pristine V₂O₅ at the other end serving as the cathode, forming a battery that is asymmetrically cycled between 0.2 V and 1.8 V. The capacity retention of this full cell (relative to 1 C values) is 95% at 5 C and 46% at 150 C, with a 1,000-cycle life. From a fundamental point of view, our all-in-one nanopore battery array unveils an electrochemical regime in which ion insertion and surface charge mechanisms for energy storage become indistinguishable, and offers a testbed for studying ion transport limits in dense nanostructured electrode arrays.
One of the greatest obstacles for the realization of the nonaqueous Li-O2 battery is finding a solvent that is chemically and electrochemically stable under cell operating conditions. Dimethyl sulfoxide (DMSO) is an attractive candidate for rechargeable Li-O2 battery studies; however, there is still significant controversy regarding its stability on the Li-O2 cathode surface. We performed multiple experiments (in situ XPS, FTIR, Raman, and XRD) which assess the stability of the DMSO-Li2O2 interface and report perspectives on previously published studies. Our electrochemical experiments show long-term stable cycling of a DMSO-based operating Li-O2 cell with a platinum@carbon nanotube core-shell cathode fabricated via atomic layer deposition, specifically with >45 cycles of 40 h of discharge per cycle. This work is complemented by density functional theory calculations of DMSO degradation pathways on Li2O2. Both experimental and theoretical evidence strongly suggests that DMSO is chemically and electrochemically stable on the surface of Li2O2 under the reported operating conditions.
batteries (e.g., Li-S battery and Li-air battery) due to the low electrochemical potential and high theoretical specific capacity of Li metal (3861 mAh g −1 ). The battery industry expended considerable effort to commercialize Li metal anodes via electrolyte additive engineering in the late 1980s. [4][5][6] However due to the instability of the Li-metal/electrolyte interface, and the formation of dangerous dendrites on Li metal surface, the use of lithium anodes decreased in popularity.The low electrochemical potential of Li metal makes it highly reactive, readily forming thin native surface layers during manufacturing. In principle, the insulating native surface layer could suppress or block electron transfer to the electrolyte, serving as a self-limiting protection layer on the Li surface to prevent solvent decomposition. However, the chemical/electrochemical instability of the interface leads to significant battery degradation through Li metal corrosion, solvent/electrolyte consumption, and flammable gas generation, largely associated with formation of a solid electrolyte interphase (SEI) layer by chargetransfer-initiated decomposition of the organic solvent. [7,8] The technology potential of Li anodes provides strong incentive to understand and prevent these Li surface degradation mechanisms at the surface of Li foils that would be employed in high energy Li anode storage systems. [9][10][11][12][13][14][15][16][17] Solvent Decomposition on Li Metal FoilsFoils of Li-metal are commonly used as negative electrode in pursuit of Li-metal batteries. Because of Li's exceptionally high reactivity, the surface is always covered with an oxide layer. We characterize the as-prepared Li foil surface by the in situ X-ray Photoelectron Spectroscopy (XPS) results in Figure 1a, where a Li metal foil was directly transferred from a purified Arfilled glovebox through ultrahigh vacuum to the XPS system, thus avoiding air exposure ( Figure S1, Supporting Information). The Li (1s) XPS spectrum indicates a mixture of Li 2 O, Li 2 CO 3 , and LiOH on the Li surface. Since prior investigations using our in situ XPS capabilities revealed no measurable carbon or carbonate following growth of Li 2 O by atomic layer deposition (ALD), [18] the presence of a carbonate feature Chemical and electrochemical instability of the Li metal interface with organic solvent has been a major impediment to use of Li-metal anodes for next-generation batteries. Here the character of Li surface degradation and the application of atomic layer deposition (ALD) as a protection layer to suppress the degradation are addressed. Using standard Li foil samples in organic solvent with and without in situ deposited ALD Al 2 O 3 protective layers, results from in situ atomic force microscopy, mass spectrometry (including differential electrochemical mass spectrometry), X-ray Photoelectron Spectroscopy (XPS), and ex situ scanning electron microscopy/energy dispersive X-ray spectroscopy are reported. Despite the presence of a thin oxide/hydroxide/carbonate layer on th...
Materials that undergo conversion reactions to form different materials upon lithiation typically offer high specific capacity for energy storage applications such as Li ion batteries. However, since the reaction products often involve complex mixtures of electrically insulating and conducting particles and significant changes in volume and phase, the reversibility of conversion reactions is poor, preventing their use in rechargeable (secondary) batteries. In this paper, we fabricate and protect 3D conversion electrodes by first coating multiwalled carbon nanotubes (MWCNT) with a model conversion material, RuO2, and subsequently protecting them with conformal thin-film lithium phosphous oxynitride (LiPON), a well-known solid-state electrolyte. Atomic layer deposition is used to deposit the RuO2 and the LiPON, thus forming core double-shell MWCNT@RuO2@LiPON electrodes as a model system. We find that the LiPON protection layer enhances cyclability of the conversion electrode, which we attribute to two factors. (1) The LiPON layer provides high Li ion conductivity at the interface between the electrolyte and the electrode. (2) By constraining the electrode materials mechanically, the LiPON protection layer ensures electronic connectivity and thus conductivity during lithiation/delithiation cycles. These two mechanisms are striking in their ability to preserve capacity despite the profound changes in structure and composition intrinsic to conversion electrode materials. This LiPON-protected structure exhibits superior cycling stability and reversibility as well as decreased overpotentials compared to the unprotected core-shell structure. Furthermore, even at very low lithiation potential (0.05 V), the LiPON-protected electrode largely reduces the formation of a solid electrolyte interphase.
Environmental regulation is a crucial way to achieve manufacturing green transformation. However, few studies have explored the spatial spillover effects and regional boundaries of environmental regulation on manufacturing carbon emissions from the perspective of local government competition. Based on the manufacturing panel data of 30 provinces in China from 2007 to 2019, this paper uses the spatial Durbin model to examine the impact mechanisms, spatial spillover effects, regional boundaries and industry heterogeneity of environmental regulation, and local government competition on manufacturing carbon emissions. The results show that (1) environmental regulation suppresses local manufacturing carbon emissions, local government competition increases local manufacturing carbon emissions, but the interaction indicates that local governments tend to top-to-top competition under the constraints of environmental regulation. (2) The spatial spillover effect of environmental regulation has regional boundaries. The regional boundary with a positive spillover effect is 600 km, and the regional boundary with a negative spillover effect is 1600 km. (3) Environmental regulation and local government competition have spatial heterogeneity in the carbon reduction effects of seven-type manufacturing industries. These findings suggest concrete evidence for developing policies for further encouraging green development in manufacturing.
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