Dual Storage Mechanism Research Articles

A High-Capacity Manganese-Metal Battery with Dual-Storage Mechanism.

As a promising post lithium-ion-battery candidate, manganese metal battery (MMB) is receiving growing research interests because of its high volumetric capacity, low cost, high safety and high energy-to-price ratio. However, the low energy density, mainly constrained by scarce choices and unsatisfying capacity of cathodes, strictly bottlenecks the development of MMBs. In this work, a new class of cathodes based on novel dual-storage mechanism (DSM) are reported. Working principles of DSM are revealed and deeply understood via ex-situ X-ray diffraction and X-ray photoelectron spectroscopy. Besides, a proof-of-concept DSM-based Cu1.8S cathode, which shows the highest specific capacity of 220 mAh g-1 and 97.1% higher energy density than previously reported cathodes in storing Mn2+ ions, is presented. The key determinants on DSM and design strategies for next-generation cathodes are revealed via theoretical calculations. This work provides a new class of high-capacity cathode materials for MMBs, which is expected to draw inspirations to further enhance the energy density of MMBs.

Dual storage mechanism of Bi2O3/Co3O4/MWCNT composite as an anode for lithium-ion battery and lithium-ion capacitor

Bismuth oxide(Bi2O3) and cobalt oxide(Co3O4) are promising owing to their unique properties, high storage capacity, low cost, and eco-friendliness, making them ideal for lithium-ion batteries(LIBs) and lithium-ion capacitors(LICs) anodes. This study presents the synthesis and thorough characterization of Bi2O3/Co3O4 and Bi2O3/Co3O4/MWCNT composites as potential LIB and LIC anode materials. The materials are synthesized using a hydrothermal process succeeded by annealing. Structural, morphological, and compositional studies were analyzed. Various tests evaluated electrochemical performance, including cyclic voltammetry(CV), confirming a dual storage mechanism like alloying and conversion reaction involved for better energy storage. Specific discharge capacities of 834 mAh/g and 1184 mAh/g were recorded for Bi2O3/Co3O4 and Bi2O3/Co3O4/MWCNT composite electrodes at a current density of 100 mA/g, respectively. The composite material exhibited notably enhanced rate capability, with 31 % and 51 % discharge capacities for Bi2O3/Co3O4 and Bi2O3/Co3O4/MWCNT, respectively. The cyclic stability assessment revealed that Bi2O3/Co3O4 and Bi2O3/Co3O4/MWCNT maintained a high coulombic efficiency of around 99 % over 250 charge–discharge cycles at a high current density of 1 A/g. The capacity retention was approximately 253 mAh/g for Bi2O3/Co3O4 and 439 mAh/g for the Bi2O3/Co3O4/MWCNT composite, indicating excellent cyclic stability and minimal energy loss during cycling. Moreover, the LICs assembly of Bi2O3/Co3O4/MWCNT//CB was investigated, revealing a power density of 200 W kg−1 alongside an energy density of 8.64 Wh kg−1. The cyclic stability assessment over 10,000 cycles exhibits a capacity retention of approximately 45 % under a high current density of 2 A/g.

Dual Storage Mechanism in Nanoscale Solid-State Lithium-Ion Supercapacitors

Dual Storage Mechanism in Nanoscale Solid-State Lithium-Ion Supercapacitors

Dual storage mechanism of charge adsorption desorption and Faraday redox reaction enables aqueous symmetric supercapacitor with 1.4 V output voltage

Preparation of heterostructure electrode materials with dual storage mechanisms of charge adsorption desorption (electric double-layer capacitance) and Faraday redox reaction (pseudo-capacitance) remains a great challenge for supercapacitors with wide operating voltage and high energy density. Herein, the heterostructure ZnO nanoparticles decorated NiFe/CNTs/rGO (ZnO-FeNi/CG) was rational designed and synthesized via a straightforward two-step hydrothermal process for supercapacitor application. The rational designed flower-like heterostructure ZnO-FeNi/CG reveals outstanding specific capacitance of 1265F/g at 1 A/g and 88.5 % capacitance retention after 10,000 cycles even at 30 A/g in three-electrode test. Benefiting from the designed unique heterostructure and the effective anti-catalytic strategy, the Faradaic redox reactions of ZnO-FeNi/CG electrode were well coordinated by HER and OER, so that water splitting process was greatly suppressed under high operating voltage in aqueous alkaline electrolytes. Thus, the fabricated symmetric supercapacitor based on the dual storage mechanisms of electric double-layer capacitance and pseudo-capacitance displays 1.4 V output voltage, ultrahigh capacitance of 227F/g (1 A/g), and exceptional energy density of 62 Wh kg−1 at power density of 1400 W kg−1 as well as extraordinary capacitance retention 84.7 % for 10,000 cycles, outperforming the previous spinel-type metal oxides/carbon-based supercapacitors in aqueous alkaline electrolytes. The dual storage mechanism of charge adsorption desorption and Faraday redox reaction can provide a pathway to design next-generation aqueous symmetric supercapacitors with wide output voltage and ultrahigh energy density for advanced energy storage systems.

Molecular engineering of interplanar spacing via π-conjugated phenothiazine linkages for high-power 2D covalent organic framework batteries

<h2>Summary</h2> Two-dimensional covalent organic frameworks (2D-COFs) represent an attractive platform for organic electrodes, yet they suffer from inferior power capability caused by poor Li⁺ intercalation in densely π-π stacked interlayers. Herein, featuring nonplanar π-conjugated heteroaromatic linkages, phenothiazine with "butterfly" conformation is integrated as a structural scaffold to instantly tune packing topology and interplanar distance. Corrugated 2D-COF maintaining aromaticity and crystallinity is formed with good electroactivity, enlarged d-spacing, and accessibility to interior Li⁺-interactive sites, which results in remarkable capacity of 220–773 mAh g⁻¹ at high rates ranging from 100 to 3,200 mA g⁻¹ with a good cycle life, bridging the performance gap between power and energy. Mechanistic studies reveal a dual storage mechanism with dominating capacitive storage promoted by π-Li⁺ interactions, as well as enhanced redox activity of carbonyls for better chemical accessibility. These findings elucidate inherent effects of molecular-level d-spacing regulation enabled by heteroaromatics, presenting a new design concept of interlayer engineering for organic porous energy storage materials.

Experimental and numerical study of gas diffusion and sorption kinetics in ultratight rocks

Mass transport in ultratight rocks is markedly different from that in typical permeable rocks due to the presence of nano-scale pores and a dual-storage mechanism in terms of free and adsorbed gas. This work provides a quantitative analysis of gas transport behavior in ultratight rocks by utilizing X-ray computed micro-computed tomography (micro-CT) imaging and numerical modeling. We conducted X-ray micro-CT core-scale experiments using high-attenuation xenon (Xe) and Marcellus shale sample to obtain temporal and spatial Xe density maps from a series of micro-CT images. We present a dual-mechanism numerical model to analyze the sorption and diffusion phenomena observed in the experiment. The numerical model considers both bulk and surface diffusion by coupling of a diffusion-based equation for free-gas transport with a surface-diffusion equation for the sorbed phase. A sorption kinetic model quantifies mass transfer between the free- and sorbed-phase. The governing equations are solved simultaneously using finite element methods. Comparisons of numerical and experimental results reveal that sorption is a non-equilibrium process in ultratight rocks and surface diffusion significantly contributes to total mass transport through nanopores. Further, results show that sorbed-phase transport a nonlinear phenomenon given the dependence of surface diffusion coefficient on concentration. Resulting transport-related parameters, such as bulk and surface diffusion coefficients and sorption rate constants, which are estimated from history matching, are consistent with literature data.

Dual Storage Mechanism Induced High Capacity Cathode for Rechargeable Aluminium Ion Battery

Rechargeable energy storage devices have attained much interest in the society as it provides solution to energy crisis. The excessive use of lithium due to ever increasing demand of lithium ion battery in stationary energy storage and portable electronic devices coupled with restricted availability, urges to move towards alternative low cost energy storage device. Developing a new type of sustainable electrochemical energy storage device depends on the exploration of electrochemistry of other alkali metals. Looking for the low cost energy storage device, Al is the third most abundant element in the Earth’s crust and can be used as low cost energy storage device. Moreover, it can exchange three redox electrons per cations so that the energy density of the battery is high compared to lithium based storage system. But the lack of suitable cathode material is the major draw back of aluminium ion battery not reaching the level of commercialization. Carbon based materials like graphite and reduced graphene oxide have been probed as a cathode material where the charge storage occurs by the in intercalation of AlCl4 - anion into the graphite interlayer which limits the specific capacity in the range of 80 to 100 mAh g-1. Cathode materials, which can also intercalate trivalent aluminium ions, can enhance the specific capacity. This work aims to design a cathode material, which can react with both Al3+ and AlCl4 – ions. Sulfur, a cost effective material, embedded in distorted multiwalled carbon nanotubes (DCNT) provides a new concept of both intercalation of AlCl4 – ions in DCNT as well as conversion reaction of sulfur with trivalent aluminium ions. This design of cathode delivers a specific capacity of 500 mAh g-1 at a current density of 50 mA g-1 with a stable cycling of about 600 cycles and can lead to the development of high energy density rechargeable aluminium ion battery.

Loofah-derived carbon as an anode material for potassium ion and lithium ion batteries

In this work, we report a facile and inexpensive strategy to synthesize loofah-derived pseudo-graphite (LPG) through alkali treatment process followed by a one-step pyrolysis procedure. This mesoporous hard carbon material offers superb dual functionality for both lithium-ion battery (LIB) and potassium-ion battery (KIB) anodes. Tested against lithium and potassium, LPG delivers a specific capacity of 225 mAh·g−1 in LIBs and 150 mAh·g−1 in KIBs after 200 cycles at the current density of 100 mA g−1. The good performance of LPG for both LIBs and KIBs mainly originates from its dual storage mechanism. On one hand, wider layered pseudo-graphite units provide space for Li+/K+ intercalation at higher voltages (>0.17 V in LIBs, > 0.56 V in KIBs). On the other hand, highly accessible mesoporous structure and defect-activated units in the near-surface region make it possible for Li+/K+ deposition at low voltages. The different performance of LPG in LIBs and KIBs may originate from varied ion-storage mechanisms. Despite the similar diffusion coefficient (D+), lower capacity of LPG for potassium can be contributed to its limited intercalation kinetics in higher voltage (>0.56 V) and evidently higher resistance in the charge-transfer process (Rct).

Rechargeable batteries with high energy storage activated by in-situ induced fluorination of carbon nanotube cathode.

High performance rechargeable batteries are urgently demanded for future energy storage systems. Here, we adopted a lithium-carbon battery configuration. Instead of using carbon materials as the surface provider for lithium-ion adsorption and desorption, we realized induced fluorination of carbon nanotube array (CNTA) paper cathodes, with the source of fluoride ions from electrolytes, by an in-situ electrochemical induction process. The induced fluorination of CNTA papers activated the reversible fluorination/defluorination reactions and lithium-ion storage/release at the CNTA paper cathodes, resulting in a dual-storage mechanism. The rechargeable battery with this dual-storage mechanism demonstrated a maximum discharging capacity of 2174 mAh gcarbon−1 and a specific energy of 4113 Wh kgcarbon−1 with good cycling performance.

Binary metal hydroxide nanorods and multi-walled carbon nanotube composites for electrochemical energy storage applications

Carbon nanotube and metal oxide/hydroxide hybrids have attracted much interest as electrode materials for electrochemical supercapacitors because of their dual storage mechanism. They can complement or replace batteries in electrical energy storage and harvesting applications, where high power delivery or uptake is needed. Multi-walled carbon nanotube (MWCNT) and nickel–cobalt binary metal hydroxide nanorod hybrids have been developed through the chemical synthesis of binary metal hydroxide on a MWCNT surface. These hybrids show enhanced supercapacitive performance and cycling ability. Growth of a thin film consisting of a coating of binary metal hydroxide, as well as further growth of nanorod structures, is demonstrated using FESEM and TEM, showing that this film is a promising structure for supercapacitor applications. These electrodes yield a significantly high capacitance of 502 F g−1 with a high energy density of 69 W h kg−1 at a scan rate of 5 mV s−1. The film is stable up to 5000 cycles with greater than 80% capacitance retention.