Batteries For Energy Storage Applications Research Articles

One-step Solid-State Synthesis of V1.13Se2/V2O3 Heterostructure as a High Pseudocapacitance Anode for Fast-Charging Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) offer several benefits, including cost-efficiency and fast-charging characteristics, positioning them as attractive substitutes for lithium-ion batteries in energy storage applications. However, the inferior capacity and cycling stability of electrodes in SIBs necessitate further enhancement due to sluggish reaction kinetics. In this respect, the utilization of heterostructures, which can provide an inherent electric field and abundant active sites on the surface, has emerged as a promising strategy for augmenting the cycling stability and rate features of the electrodes. This work delves into the utilization of V1.13Se2/V2O3 heterostructure materials as anodes, initially fabricated via a simplified one-step solid-state sintering technique. The high pseudocapacitance and low characteristic relaxation time constant give the V1.13Se2/V2O3 heterostructure impressive properties, such as a high capacity of 328.5 mAh g-1 even after 1500 cycles at a high current density of 2 A g-1 and rate capability of 278.9 mAh g-1 at 5 A g-1. Moreover, the assembled sodium-ion full battery delivers a capacity of 118.5 mAh g-1 after 1000 cycles at 1 A g-1. These findings provide novel insight and guidance for the rapid synthesis of heterojunction materials and the advancement of SIBs.

(Invited) All-Solid-State Na- and K-Ion Batteries with Dry Polymer Electrolytes

The development of sodium-ion and potassium-ion batteries has gained increasing attention as a sustainable and cost-effective alternative to lithium-ion batteries, due to the abundance of their constituent elements.[1]-[3] All-solid-state batteries offer high safety advantages in high-temperature conditions, as their solid composition reduces the risk of leakage or ignition of the organic electrolyte. As large-scale and stationary batteries for energy storage applications require safety and durability in wide-temperature operations, all-solid-state sodium-ion and potassium-ion batteries can provide a potential solution.This study presents the fabrication of all-solid-state sodium batteries, using dry polymer electrolytes, optimized for stable operation at 60 °C.[4] A composite electrode with uniformly dispersed conductive carbon and binder polymer is essential to achieve a stable charge-discharge reaction in all-solid-state cell, due to the absence of the liquid electrolyte penetrated in the electrode pores. The use of a polymer electrolyte as a binder polymer provides an effective ionic conduction path inside the electrode, which allows stable charge-discharge reaction even at the thick composite electrodes. The fabricated all-solid-state Na // P2-Na2/3[Ni1/3Mn2/3]O2 cell exhibits superior cycle performance at 60 °C, compared to the liquid electrolyte. Furthermore, coating P2-Na2/3[Ni1/3Mn2/3]O2 with Al-oxide enhances the capacity retention of the P2-Na2/3[Ni1/3Mn2/3]O2 // hard carbon full cell, with a mean discharge voltage of 3.11 V and energy density of 148 Wh (kg of active material)−1. To the best of our knowledge, this is the highest value ever reported for full-cell operation of an all-solid-state sodium-ion battery using a dry-polymer electrolyte.The study also reports the fabrication of all-solid-state potassium batteries, where the effects of K metal pretreatment on the K metal/solid polymer electrolyte interface were investigated.[5] The use of K metal chunk, pretreated with the electrolytes containing potassium bis(fluorosulfonyl)amide (KFSA), effectively suppressed polarization and interfacial resistance during continuous K metal stripping-deposition reactions in the cross-linked polymer electrolyte, poly[ethylene oxide-co-2-(2-methoxyethoxy)ethyl glycidyl ether-co-allyl glycidyl ether] (P(EO/MEEGE/AGE)). The addition of 1,3,2-dioxathiolane 2,2-dioxide (DTD) to the pretreatment solution further decreased polarization and interfacial resistance, due to the formation of a stable passivation layer on K metal by FSA− ions and DTD. The efficient operation of the potassium iron hexacyanoferrate positive electrode and graphite negative electrode in P(EO/MEEGE/AGE), with the K metal counter electrode, was achieved by effectively suppressing interfacial resistance through pretreatment. Stable K metal counter electrode for all-solid-state potassium cell was also beneficial to design full cell of all-solid-state potassium-ion cell, enabling us to fabricate the first 3 V-class all-solid-state K-ion battery operated at room temperature.

Effect of Annealing Temperature on the Electrochemical Behavior of Hydrothermal Assisted Bismuth Phosphate Nanostructures

: In the present scenario, society requires various energy sources due to the depletion of fossil fuels. In the current work, Bismuth Phosphate nanostructures are synthesized via the hydrothermal method at different aging periods and were further annealed at 300 These samples are abbreviated as BP6300, BP12300, BP18300, and BP24300. Further, we analyzed the synthesized samples' structural, morphological, and electrochemical behavior. X-ray Diffraction Technique is used to analyze the phase and crystal structure of all the synthesized samples. A field emission scanning electron microscope (FESEM) is used to analyze the morphology. Raman and FTIR spectra also approved the structure of materials and functional groups of all the synthesized samples. EDX spectra analysis confirmed the results quantitatively by detecting all the elements present in the synthesized material. High–resolution X-ray photoelectron spectroscopy (XPS) spectra confirmed the oxidation states of the synthesized samples. Various aging period treatments with annealing temperatures play a significant role in tuning the electrochemical behavior of working electrodes for battery or hybrid energy storage applications. The drop casting method was adopted for the fabrication of working electrodes, and all the electrochemical analysis of these electrodes was done in the 2 M KOH electrolyte solution. Cyclic Voltammetry (CV), Galvanostatic Charge Discharge (GCD), and Electrochemical Impedance Spectroscopy (EIS) of all the samples were analyzed in the 3-electrode setup and exhibited a high potential window of 1.4 V. The specific capacity is found to be maximum for BP12300 samples. The investigation revealed that synthesized material could be used as an electrode for various energy storage device applications. Keywords: Bismuth Phosphate, Cyclic Voltammetry, Galvanostatic charge-discharge, and hydrothermal method.

Life cycle assessment of experimental Al-ion batteries for energy storage applications

In this work, the analysis of environmental performance and its coherence with circular economy priorities of different variants of Al-ion battery construction was performed. Al-ion-based batteries can be considered as one of the future alternatives for currently used Li-ion-based cells when the shortage of lithium or cobalt becomes a challenge.All tested batteries were constructed with Al anodes, polypropylene foil separator, polyvinylidene fluoride + N-Methyl-2-pyrrolidone (PVDF+NMP) binder, Al collector and laminated Al foil pouch cell. WO3, Norit and carbon from potato starch (CPS) were used as a cathode material. Saturated solutions of AlCl3 dissolved in diethylene glycol dimethyl ether (DEG) and deep eutectic solvents (DES) originating from bacterial polymer polyhydroxyalkanoate were used as electrolytes.The ReCiPe impact assessment method was used in this analysis. The indicator in this study was ReCiPe Endpoint (H) V1.07 referring to Europe. SimaPro 9.4 software with Ecoinvent 3.8 inventory database were used for all calculations. The analysis included experimental production and assembly of batteries and their end-of-life processing.Based on the performed analysis it was found that the overall weighted impact of each single construction variant of an Al-ion battery is dominated by the use of electricity, no matter which variant is considered since it is related to the electricity mix in Poland and its high dependence on fossil fuels. Overall environmental impact is the smallest for CPS DEG battery, while Norit DEG and CPS DEG variants have slightly higher impacts. The share of end-of-life processing in overall environmental impacts of all analysed variants was found low compared to the Li-ion batteries. This observation indicates the Al-ion batteries as a promising direction of alternative electrochemical devices for energy storage systems while end-of-life processing and circular solution are concerned.

Advancements and Challenges in Aqueous Zinc-Ion Batteries: Mechanisms, Materials, Electrolytes, and Interface Engineering

Rechargeable aqueous zinc-ion batteries hold significant promise as a safer and more environmentally friendly alternative to conventional lithium-ion batteries for energy storage applications. This paper provides a comprehensive overview of the charge storage mechanism, electrode materials, electrolyte considerations, and electrode interface challenges in aqueous zinc-ion batteries. The complex charge storage mechanism involving zinc ion movement between the cathode and zinc metal anode is discussed in detail. Anode and cathode material selections and design strategies are explored, highlighting their pivotal roles in determining battery performance, energy density, cycle lifespan, and stability. The critical influence of electrolyte choice and design on battery performance is also elucidated, emphasizing the interplay between high ionic conductivity, stability, temperature range, and cost. The paper further delves into the challenges and advancements related to optimizing the electrode interface, addressing issues such as dendrite growth, electrode passivation, and side reactions. Finally, future research directions and strategies to overcome current limitations are outlined, underscoring the potential of aqueous zinc-ion batteries as a viable and sustainable energy storage solution.

Rechargeable Hydrogen-Chlorine Battery Operates in a Wide Temperature Range.

Hydrogen-chlorine (H2-Cl2) fuel cells have distinct merits due to fast electrochemical kinetics but are afflicted by high cost, low efficiency, and poor reversibility. The development of a rechargeable H2-Cl2 battery is highly desirable yet challenging. Here, we report a rechargeable H2-Cl2 battery operating statically in a wide temperature ranging from -70 to 40 °C, which is enabled by a reversible Cl2/Cl- redox cathode and an electrocatalytic H2 anode. A hierarchically porous carbon cathode is designed to achieve effective Cl2 gas confinement and activate the discharge plateau of Cl2/Cl- redox at room temperature, with a discharge plateau at ∼1.15 V and steady cycling for over 500 cycles without capacity decay. Furthermore, the battery operation at an ultralow temperature is successfully achieved in a phosphoric acid-based antifreezing electrolyte, with a reversible discharge capacity of 282 mAh g-1 provided by the highly porous carbon at -70 °C and an average Coulombic efficiency of 91% for more than 300 cycles at -40 °C. This work offers a new strategy to enhance the reversibility of aqueous chlorine batteries for energy storage applications in a wide temperature range.

In situ observation of the electrochemical behavior of Li–CO2/O2 batteries in an environmental transmission electron microscope

AbstractLi–CO2/O2 batteries, a promising energy storage technology, not only provide ultrahigh discharge capacity but also capture CO2 and turn it into renewable energy. Their electrochemical reaction pathways' ambiguity, however, creates a hurdle for their practical application. This study used copper selenide (CuSe) nanosheets as the air cathode medium in an environmental transmission electron microscope to in situ study Li–CO2/O2 (mix CO2 as well as O2 at a volume ratio of 1:1) and Li–O2 batteries as well as Li–CO2 batteries. Primary discharge reactions take place successively in the Li–CO2/O2–CuSe nanobattery: (I) 4Li+ + O2 + 4e− → 2Li2O; (II) Li2O + CO2 → Li2CO3. The charge reaction proceeded via (III) 2Li2CO3 → 4Li+ + 2CO2 + O2 + 4e−. However, Li–O2 and Li–CO2 nanobatteries showed poor cycling stability, suggesting the difficulty in the direct decomposition of the discharge product. The fluctuations of the Li–CO2/O2 battery's electrochemistry were also shown to depend heavily on O2. The CuSe‐based Li–CO2/O2 battery showed exceptional electrochemical performance. The Li–CO2/O2 battery offered a discharge capacity apex of 15,492 mAh g−1 and stable cycling 60 times at 100 mA g−1. Our research offers crucial insight into the electrochemical behavior of Li–CO2/O2, Li–O2, and Li–CO2 nanobatteries, which may help the creation of high‐performance Li–CO2/O2 batteries for energy storage applications.

Model predictive and SoC balancing control of a CHB inverter in battery energy storage application using reward functions

SummaryThis article presents an improved model predictive current control algorithm combined with a novel state of charge (SoC) balancing approach for a three‐phase cascaded H‐bridge inverter in battery energy storage applications. Based on the model predictive control with elimination of redundant voltage vectors, neighboring vectors of the last voltage vectors are used to find the optimal ones in only one control cycle, which solves the problems of high computational burden and slow dynamic response. To overcome the unsuitability of the conventional cost function in SoC balancing, the reward functions that effectively balance the inter‐phase SoCs, inner‐phase SoCs, and inner‐phase dc voltages are presented respectively. Simulation and hardware‐in‐the‐loop‐based experimental results validate the effectiveness of the proposed strategy.

Dimerizing Lawsone into Bis-lawsone to Counter Solubility and Attain Facile Zn2+ Ion Diffusion for Stable Capacity in Aqueous Zinc-Ion Batteries

Given the higher volumetric capacity of Zn (5853 mAh cm−3), aqueous zinc-ion batteries can be considered as alternatives to lithium-ion batteries for energy storage applications. Here we focus on redox-active, non-toxic, and eco-friendly organic materials with quinone moiety, i.e., Lawsone (LS) and its dimer Bis-lawsone (BL), as a cathode material for Zn-ion batteries. The reversibility of LS and BL is confirmed by cyclic voltammetry between 0.3 and 1.6 V in zinc sulfate and zinc triflate electrolytes. The electrochemical performance of BL in the zinc triflate electrolyte is improved by the reduction in the solubility of BL in the electrolyte and improvement in Zn2+ diffusion in the BL matrix. Besides, it is known that Zn electrodes passivate better in zinc triflates, which contributes to improved plating/stripping of Zn. The dimerization strategy counteracts solubility and facilitates the diffusion of Zn2+, resulting in a stable charge–discharge with a specific capacity of 200 mAh g–1. The cell attained 77% of the theoretical capacity at a current density of 100 mA g–1. Zn-BL cells show fast kinetics and reversibility for up to 760 cycles retaining 85% of initial capacity despite the partial solubility of BL in electrolytes. In addition, the Nafion-212 membrane is introduced as a separator instead of a traditional glass fiber separator. The negatively charged backbone of Nafion helps eliminate the crossover problem by coulostatic repulsion with negatively charged BL and LS.

In-situ imaging electrocatalysis in a solid-state Li-O2 battery with CuSe nanosheets as air cathode

The development of highly efficient catalysts in the cathodes of rechargeable Li-O2 batteries is a considerable challenge. To enhance the electrochemical performance of the Li-O2 battery, it is essential to choose a suitable catalyst material. Copper selenide (CuSe) is considered as a more promising cathode catalyst material for Li-O2 battery due to its better conductivity and rich electrochemical active sites. However, its electrochemical reaction and fundamental catalytic mechanism remain unclear till now. Herein, in-situ environmental transmission electron microscopy technique was used to study the catalysis mechanism of the CuSe nanosheets in Li-O2 batteries during discharge and charge processes. It is found that Li2O was formed and decomposed around the ultrafine-grained Cu during the discharge and charge processes, respectively, demonstrating excellent cycling. This indicate that the freshly formed ultrafine-grained Cu in the conversion reaction catalyzed the latter four-electron-transfer oxygen reduction reaction, leading to the formation of Li2O. Our study provides important understanding of the electrochemistry of the Li-O2 nanobatteries, which will aid the development of high-performance Li-O2 batteries for energy storage applications.

3D‐Printed Hydrogels and Aerogels for Water Treatment and Energy Storage Applications

AbstractRecently, three‐dimensional (3D) printing has become a research focus point and has evolved as a powerful tool for manufacturing complex objects for advanced technology platform designs. Herein, we review the current state‐of‐the‐art 3D‐printed hydrogels and aerogels for wastewater treatment and energy storage applications. Several 3D printing methods such as direct ink writing, digital light processing, and fused filament fabrication have been discussed. Among these, direct ink writing is the most employed 3D printing technique for hydrogels and aerogels. We systematically investigated the most important results of several 3D‐printed hydrogels and aerogels for adsorption, photocatalysis, membrane filtration, and desalination for wastewater treatment, supercapacitors, and batteries in energy storage applications. Finally, we conclude our understanding with the prospect of future opportunities in this field using 3D‐printed hydrogels and aerogels for wastewater treatment and energy storage applications. In summary, the fundamental knowledge of 3D printing and critical assessment of the key literature on 3D‐printed hydrogels and aerogels and their applications in water treatment and energy storage will provide guidance for future studies in smart materials and waste management aspects of sustainability.

Ordered LiFe5O8 thin films prepared by pulsed laser deposition as an anode material for all-solid thin film batteries

The search for obtaining a Co free low-cost and high-capacity anode thin film material for high energy density all-solid thin film batteries has been driving the increasing innovation and research in Li-ion battery (LIB) technology. In the present case, LiFe5O8 (LFO) thin films are prepared by pulsed laser deposition (PLD) technique and their electrochemical properties, Li ion dynamics, conducting processes at various frequencies and current rates are explored. LFO thin films are seen to crystallize in ordered α -phase with an inverse spinel structure. Chemical state of all the elements is analysed using X-ray photoelectron spectroscopy method. Cyclic voltammeter (CV) study carried out between 0–3 V shows the reduction peak at 0.76 V initially and in the later cycles at 0.86 V with a small shift depicting the exact conversion type behaviour of the LFO thin film. LFO thin film exhibits specific discharge capacity of 25 μAh/cm2 at 10 μA/cm2 current density during the first cycle. Rate capability measurements are carried out at various current densities of 10, 20, 30, 40, 50 and 10 μA/cm2. Li-ion diffusion coefficient during the de-lithiation and lithiation process is seen to be 3.78 × 10−14 cm2/s and 1.41 × 10−13 cm2/s, respectively. CV studies at various scan rates indicates that the mechanism of Li+ storage is dominated by a diffusion-controlled process at low scan rates and with increasing scan rate it becomes a surface-controlled process. Electrochemical impedance studies at various frequencies shows the decrease in charge transfer resistance with increasing cycles. Combined structural, chemical, electrochemical and impedance studies of LFO thin films indicates that these films can be employed for fabricating Co and Ni free all-solid thin film Li-ion batteries for energy storage applications.

Three-dimensional carbon foam decorated with SnO2 as multifunctional host for lithium sulfur batteries.

Lithium-sulfur (Li-S) batteries with high theoretical capacity and abundant sulfur resources are potential energy storage systems. Nevertheless, there are several roadblocks that strongly limit the commercial application of Li-S batteries, including the insulating nature of sulfur and Li2S, large volume change and the shuttle effect of lithium polysulfides. Herein, a three-dimensional carbon foam (CF) decorated with SnO2 (SnO2/CF) is fabricated by the simple electrodeposition and used as a sulfur host to resolve the bottleneck issues in Li-S batteries. Thanks to the synergetic effect of the polar SnO2 and conductive carbon framework, the SnO2/CF framework is endowed with multifunctionalities such as providing three-dimensional conductive framework, inhibiting the migration of polysulfides and improved reaction kinetics. Consequently, durable cycle performance with a capacity of 458.2 mAh g-1 after 1000 cycles at 1 C is achieved. Furthermore, a high capacity of 749.5 mAh g-1 at a high rate of 5 C is attained. Remarkably, under high sulfur loading of 8.84mgcm-2, the S@SnO2/CF cathode can still deliver a high specific capacity of 389.8 mAh g-1 after 300 cycles at 0.5 C. This work demonstrates a novel strategy to improve the performance of Li-S batteries for energy storage applications.

High-Performance Power Electronic Battery Pack Based on a Back-to-Back Converter

This work studies a full-power, module-integrated back-to-back converter for battery energy storage applications. The proposed solution optimizes bank usage across a wide range of individual battery capacities. The converter design and control are examined, as well as the use of a loss reduction method when operating under a partial load. The suggested architectural work allows the bank to have a regulated voltage output, simulating a passive bank, while controlling the charge and discharge of individual batteries to their maximum capacities. Those capabilities are also evaluated using linear programming optimization, in order the quantify the advantage. The suggested system is used in a typical use-case examined experimentally. The energy provided by an experimental lead acid bank rose 38 times after a few charge/discharge cycles.

Next generation sodium-ion battery: A replacement of lithium

The demands for Sodium-ion batteries for energy storage applications are increasing due to the abundance availability of sodium in the earth’s crust dragging this technology to the front raw. Furthermore, researchers are developing efficient Na-ion batteries with economical price and high safety compared to lithium to replace Lithium-ion batteries. The performance of sodium-ion batteries significantly depends on the cathode; anode and electrolyte components. In the present review paper, we discuss cathode, anode, solid electrolyte, binders and addictives properties and their performance. Furthermore, the strong and weak points of every metal and compound were discussed and analyzed in this paper. A detailed comparison of the electrical conductivity performance of solid electrolyte materials is done to find their suitability for next-generation Na-ion battery applications.

High temperature electrochemical discharge performance of LaFeO3 coated with C/Ni as anode material for NiMH batteries

Perovskite LaFeO3 is considered as a promising new anode material for nickel/metal hydride batteries due to its low cost, environmental friendliness and high temperature resistance. However, the poor conductivity of LaFeO3 material restricts the discharge ability, which is problematic for its future widespread application. To solve the above issue, in this study, we prepared C/Ni-coated LaFeO3 composite in view of the excellent electrical conductivity of carbon and nickel metal. Results show that the C/Ni-coated LaFeO3 composite delivers remarkably increased discharge capacity of ∼345 mAh g−1 at 60 ​°C in contrast to ∼267 mAh g−1 for pure LaFeO3. Furthermore, the carbon and nickel not only increase the electrical conductivity of the LaFeO3 but also reduces the agglomeration of the LaFeO3, therefore, the C/Ni-coated LaFeO3 composite serves superior long cycle-life, which maintains 60.9% after 100 cycles (52.9% for the LaFeO3 sample). In overall, the electrochemical behavior of the C/Ni-coated LaFeO3 composite confirms its high potential as nickel/metal hydride batteries for energy storage applications.

Cryo-EM Revealing the Origin of Excessive Capacity of the Se Cathode in Sulfide-Based All-Solid-State Li-Se Batteries.

Selenium (Se), whose electronic conductivity is nearly 25 orders higher than that of sulfur (S) and whose theoretical volumetric capacity is 3254 mAh cm-3, is considered as a potential alternative to S to overcome the poor electronic conductivity issue of the S cathode in the lithium (Li)-S battery. However, the study of the Li-Se battery, particularly a Li-Se all-solid-state battery (ASSB), is still in its infancy. Herein, we report the performance of Li-Se ASSBs at both room temperature (RT) and high temperature (HT, 50 °C), using a Li10Si0.3PS6.9Cl1.8 (LSPSCl) solid-state electrolyte and Li-In anode. With a Se loading of 7.6 mg cm-2, the Li-Se battery displayed a record high reversible capacity of 6.8 mAh cm-2 after 50 cycles at HT, which exceeds the theoretical areal capacity of 5.2 mAh cm-2 for Se. Moreover, the RT Li-Se ASSB delivered an initial areal capacity of about 2 mAh cm-2 at a current density of 1 A g-1 for 1200 cycles with a capacity retention of 67%. Cryo-electron microscopy revealed that the excessive capacity of Se at HT can be attributed to the formation of a previously unknown S5Se4 phase during charging, which participated reversibly in a subsequent redox reaction. The formation of the S5Se4 phase originated from the reaction of Se with S, which was generated by the decomposition of LSPSCl at HT. These results unlock the electrochemistry of a Li-Se ASSB, suggesting that a Li-Se ASSB is a viable alternative to a Li-S battery for energy storage applications.

MgSc2Se4 Solid Electrolyte for Rechargeable Mg Batteries: An Electric Field‐Assisted All‐Solid‐State Synthesis

Magnesium scandium chalcogenide spinels are an important class of materials in Mg anode‐based batteries for energy storage applications. The applications of these intriguing materials are not limited to the energy storage, but the use of these materials may also be useful in solar cells, owing to the material optical bandgap. So far, all reported synthetic routes for these spinels involve high‐temperature furnace treatment. Herein, a process which involves a facile electric field‐assisted synthesis of MgSc2Se4 is reported on, yielding after a very short thermal treatment, a material possessing a low room‐temperature electronic conductivity of ≈10−11 S cm−1, and a room‐temperature Mg‐ion conductivity of 1.78 × 10−5 S cm−1. The crucial role of extra selenium on the material electronic conductivity is discussed and explained in detail.

Oxygen-enriched vacancy spinel MFe2O4/carbon (M = Ni, Mn, Co) derived from metal-organic frameworks toward boosting lithium storage

Transition metal oxide anode materials have recently been losing their importance as advanced functional and smart materials due to early capacity decay and sluggish kinetics. In order to address this issue, vacancy engineering approach can be adapted, which can effectively manipulate the electronic structure of transition metal oxide (TMO)-based electrode materials. Herein, a series of MOF-derived oxygen-rich vacancy MFe2O4/C (M = Ni, Mn, Co) materials are synthesized on a large scale via solvothermal and subsequent calcination treatment for energy storage applications in lithium-ion batteries. All the synthesized OV-NFO (NiFe2O4), OV-MFO (MnFe2O4) and OV-CFO (CoFe2O4) electrodes achieve excellent electrochemical performance, superior multiplier performance and incredible lithium-ion diffusion rate, which was found to be superior than their counterpart electrodes. The oxygen vacancy (OV) enrichment contribution to higher conductivity was realized by experimental and density functional theory (DFT) calculations results, where it has been established that OV provides additional active sites, accelerates Li+ diffusion and improves pseudocapacitive contribution. This vacancy-engineering strategy for modulating electronic structure and reaction kinetics enabled new ideas for the design and execution of other advanced transition metal-based electrode materials.

The Advent of Aqueous >2.85V Zn-MnO2 Batteries: Uncovering Novel Mechanisms in This New High Voltage Chemistry

Alkaline zinc (Zn)-manganese dioxide (MnO2) batteries are ubiquitous, safe, cheap and used in several applications that require only a single discharge. Its impact in the developing world has been significant where its affordability has helped consumers with low to medium economic background power several of their household devices and flashlights when grid reliability has been poor. Its single discharge is enough to deliver an energy density of ~400Wh/L. However, its promising characteristics are outweighed by its limited use in the next generation of green energy technologies because of the irreversibility of its active materials and its low nominal voltage of ~1.3V. The application of battery energy storage in these next generation of technologies like grid-storage, electric vehicles and personal electronics is extremely vital to decarbonize our future. Currently, expensive, toxic and flammable lithium-ion and lead acid batteries dominate these fields. If Zn-MnO2 batteries could be made rechargeable with an increase in its nominal voltage and capacity utilized, it could be serious contender to the dominant lithium-ion and lead acid batteries.In this presentation, we report on an innovative approach where we solve the two aforementioned issues by redesigning the battery system to have two electrolytes that are decoupled from each other(1). The two electrolytes are aqueous-based, where the cathode and anode are immersed in mildly acidic solutions and alkaline solutions, respectively. Operating in decoupled electrolytes allows the chemistry to widen its potential window and access voltages of >2.85V, while also allowing the respective electrodes operate efficiently and reversibly in their respective electrolyte system. The neutralization of these electrolytes is prevented by gelation of the alkaline electrolyte, which removes the need of expensive ion-exchange membranes. As a demonstration of this concept, we have developed Zn-MnO2 batteries reaching voltages >2.85V that are able to access the theoretical capacity (617mAh/g) of MnO2. This translates to energy densities 2 to 3 times greater than the commercially available alkaline batteries that can be recharged multiple times at costs that are comparable to primary batteries (~$20-30/kWh). G. Yadav et al., ACS Energy Lett. 2019, 4(9), 2144-2146.