Zinc Manganese Dioxide Batteries Research Articles

Electrode interface modulation using 1,3-propane sultone functionalized additives for high-performance Zn-MnO2 aqueous batteries

Rechargeable aqueous zinc-manganese dioxide (Zn-MnO2) batteries have gained significant attention in the field of energy storage systems owing to their cost-effectiveness, environmental friendliness, power, and ability to mitigate thermal propagation. However, Zn- MnO2 batteries encounter challenges and limitations, including capacity degradation and voltage hysteresis by the dissolution of Mn ions in the bulk electrolyte. In this study, interfacial stabilization is improved by promoting the decomposition of the 1,3-propane sultone (PS) electrolyte additive, which occurs close to the oxidation decomposition at 1.5 V. This facilitates the formation of a stable cathode–electrolyte interphase (CEI) and effectively suppresses Mn-ion dissolution. Density functional theory (DFT) simulations provide insights into the formation of a CEI layer product structure during cell operation, resulting in the thermodynamically reduced dissolution of Mn (Mn2+) into the electrolyte when a sulfur-based decomposed layer covers MnO2. Consequently, the cathode protection layer ensures high cycle retention, Coulombic efficiency, and high C-rate cell operating conditions for the Zn-MnO2 battery cell. This work presents a promising strategy for designing electrolytes to develop high-performance aqueous zinc-ion batteries.

Achieving High Ionic Conductivity and Mechanical Strength by a Leather Gel Electrolyte for Flexible Zinc-Ion Batteries.

The continuous advancement in the field of flexible and wearable electronics has led to increased research interest in safe, low-cost, and flexible zinc-ion batteries, particularly with a focus on flexible electrolytes. In this study, we present a leather gel electrolyte (LGE) that offers robust mechanical properties and an excellent electrochemical performance. LGE exhibits an ionic conductivity of 1.36 × 10-2 S cm-1 and achieves a capacity of 303.7 mAh g-1 in flexible zinc-manganese dioxide batteries. Even after 1000 cycles, the capacity retention remains above 90%, demonstrating outstanding performance in protecting the zinc anode. Furthermore, such a flexible battery shows good resistance to damage due to the strong mechanical strength originating from leather. Notably, LGE utilizes green and sustainable leather as a raw material, making it a promising option for sustainable flexible devices.

An intrinsically self-healing and anti-freezing molecular chains induced polyacrylamide-based hydrogel electrolytes for zinc manganese dioxide batteries

The anti-freezing strategy of hydrogels and their self-healing structure are often contradictory, it is vital to break through the molecular structure to design and construct hydrogels with intrinsic anti-freezing/self-healing for meeting the rapid development of flexible and wearable devices in diverse service conditions. Herein, we design a new hydrogel electrolyte (AF/SH-Hydrogel) with intrinsic anti-freezing/self-healing capabilities by introducing ethylene glycol molecules, dynamic chemical bonding (disulfide bond), and supramolecular interaction (multi-hydrogen bond) into the polyacrylamide molecular chain. Thanks to the exceptional freeze resistance (84% capacity retention at −20 °C) and intrinsic self-healing capabilities (95% capacity retention after 5 cutting/self-healing cycles), the obtained AF/SH-Hydrogel makes the zinc||manganese dioxide cell an economically feasible battery for the state-of-the-art applications. The Zn||AF/SH-Hydrogel||MnO2 device offers a near-theoretical specific capacity of 285 mA h g−1 at 0.1 A g−1 (Coulombic efficiency ≈100%), as well as good self-healing capability and mechanical flexibility in an ice bath. This work provides insight that can be utilized to develop multifunctional hydrogel electrolytes for application in next generation of self-healable and freeze-resistance smart aqueous energy storage devices.

(Invited) Development of Commercial-Scale High Energy Density Aqueous Zinc Manganese Dioxide Alkaline Batteries for Long Duration Storage

Alkaline zinc manganese dioxide batteries are attractive for grid related energy storage applications but have been limited to relatively low utilization of the active materials to assure good cycling performance. Zinc anodes tend to deteriorate due to shape change, passivation, and dendrite formation during charge/discharge cycles. Manganese dioxide cathodes also deteriorate due to formation of inactive crystalline polymorphs during cycling. Recent work using additives in both the anodes and the cathodes has mitigated these issues and enabled access of much higher active material utilization levels, up to 50% of the two-electron capacity of the zinc and over 75% of the two-electron capacity of the manganese dioxide electrodes. Commercial-scale cylindrical (jelly roll) cells of 150 to 200 Wh, particularly suitable for long duration energy storage with discharge periods from a day to a week, have been manufactured on a pilot line. Their performance and various deployments will be discussed indicating areas where future developments would be of importance.

A Short Review: Comparison of Zinc–Manganese Dioxide Batteries with Different pH Aqueous Electrolytes

As the world moves towards sustainable and renewable energy sources, there is a need for reliable energy storage systems. A good candidate for such an application could be to improve secondary aqueous zinc–manganese dioxide (Zn-MnO2) batteries. For this reason, different aqueous Zn-MnO2 battery technologies are discussed in this short review, focusing on how electrolytes with different pH affect the battery. Improvements and achievements in alkaline aqueous Zn-MnO2 batteries the recent years have been briefly reviewed. Additionally, mild to acidic aqueous electrolyte employment in Zn-MnO2 batteries has been described, acknowledging their potential success, as such a battery design can increase the potential by up to 2 V. However, we have also recognized a novel battery electrolyte type that could increase even more scientific interest in aqueous Zn-MnO2 batteries. Consisting of an alkaline electrolyte in the anode compartment and an acidic electrolyte in the cathode compartment, this dual (amphoteric) electrolyte system permits the extension of the battery cell potential above 2 V without water decomposition. In addition, papers describing pH immobilization in aqueous zinc–manganese compound batteries and the achieved results are reported and discussed.

Sustainable high-energy aqueous zinc–manganese dioxide batteries enabled by stress-governed metal electrodeposition and fast zinc diffusivity

Beyond the fragile glass fiber separator, we demonstrated a polymer separator with good mechanical strength and fast Zn2+ diffusivity, which synergistically mitigates Zn dendrite formation and improves Zn reversibility at high capacity.

Synergistic combination of a Co-doped σ-MnO2 cathode with an electrolyte additive for a high-performance aqueous zinc-ion battery

The key challenges in aqueous zinc-manganese dioxide batteries (MnO2//Zn) are their poor electrochemical kinetics and stability, which are mainly due to low conductivity and the inevitable dissolution of MnO2. A synergistic combination of a Co-doped σ-MnO2 electrode (Co-MnO2) and a Co(CH3COO)2•4H2O (CoAc) electrolyte additive is here developed to design a high-performance aqueous MnO2//Zn battery (denoted as a Co-MnO2//Zn battery with CoAc). The introduction of Co ions (Co3+/Co2+) into the σ-MnO2 electrode is achieved via a facile one-step electrodeposition method. Benefitting from the synergistic coupling effect of the Co-MnO2 electrode and the CoAc electrolyte additive, the fabricated Co-MnO2//Zn battery with CoAc shows a commendable discharge capacity of 313.8 mAh g−1 at 0.5 A g−1, excellent rate performance, excellent durability over 1000 cycles (∼ 92% capacity retention at 1.0 A g−1) and admirable energy density (439.3 Wh kg−1), which is a significant improvement compared with an un-doped σ-MnO2//Zn battery.

Identifying interfacial mechanisms limitations within aqueous Zn-MnO2 batteries and means to cure them with additives

Li-ion batteries are playing a key role within the field of electrical mobility, grid applications and related objects owing to their high energy densities and long lifetime, but their sustainability remains to be improved. Pushing in this direction, there is a rising interest towards rechargeable aqueous batteries. Great efforts are devoted to turn the primary alkaline zinc-manganese dioxide batteries that have dominated the primary battery applications into rechargeable systems. This turns out to be a colossal task owing to the complexity of the Zn-MnO 2 chemistry that is not yet fully rationalized, thus causing delay in practical deployment. In this work we revisit this chemistry by combining fundamental solution chemistry considerations and complementary analytical techniques (TEM, Raman spectroscopy and EQCM) together with the assembly of cells using either MnO 2 or MnO 2 -free initial positive electrodes. We confirm the key role of the electrolyte together with the inseparable link between its pH and the system's electrochemical response. Moreover, during discharge and charge, we provide experimental evidence for the occurrence of MnO 2 electrodissolution and back electrodeposition conjointly with the formation of soluble zinc hydroxides up to chemical precipitation and back dissolution of a Zn 4 SO 4 (OH) 6 .xH 2 O phase. We show that this phase is essential in the buffering of the system's pH and demonstrate the beneficial role of its initial presence in the positive electrode composite. Further pushing the idea of buffering the pH of the electrolyte, we propose the use of additives such as ZnO, Mg(OH) 2 or La(OH) 3 that enhance the capacity retention upon cycling, while slightly penalize the cell capacity. These insights provide missing links regarding the interplay between the conjoint electrochemical-chemical reactions ruling the functioning of rechargeable Zn-MnO 2 batteries, hence providing a step forward towards their development.

Ion-Selective Graphene Oxide/Polyvinyl Alcohol Composite Membranes for Rechargeable Alkaline Zinc Manganese Dioxide Batteries

Blocking the zincate ion ([Zn(OH)4]2–) and limiting its reaction with the cathode material are key requirements for improving the energy density and rechargeability of alkaline zinc manganese dioxide (Zn|MnO2) batteries. Zincate is the soluble anode discharge product, which undergoes a side reaction with the reduced cathode material to form a resistive and irreversible spinel material. Such a side reaction prevents deeper discharge of MnO2, reduces the battery’s achievable energy, and prevents it from further cycling. In this article, we report the design and fabrication of an ion-selective graphene oxide/poly(vinyl alcohol) composite membrane and demonstrate its superiority in suppressing zincate ion crossover while minimally impairing the conduction of hydroxyl ions (OH–). With this advanced separator, near full utilization of the MnO2 electrode’s two-electron capacity (∼617 mA h/g-MnO2) with a high areal capacity of 20 mA h/cm2 is reported for both primary and secondary cells. In the primary cell, the energy density is almost doubled, and in the rechargeable cell, a cycle life of 300 cycles is achieved, which is more than 3 times better than the case with no zincate blocking separator.

(Invited, Digital Presentation) Zinc-Based Energy Storage System Deployments and Developments for Transition to a Clean Energy Future

Rechargeable zinc-based alkaline batteries are an attractive electrochemical energy storage option with zinc anode costs of $3/kWh at full (theoretical) 2 electron capacity. When paired with high-capacity, inexpensive cathodes like manganese dioxide, and accounting for incomplete utilization of the active materials capacities, inactive materials costs (like for current collectors etc.) and manufacturing costs, rechargeable zinc-manganese dioxide batteries costing about $20-30/kWh appear to be within reach. The challenges to meeting these cost targets, and the current status of such rechargeable zinc alkaline batteries will be discussed. The first generation of rechargeable zinc-manganese dioxide batteries are now being deployed in residential, commercial, and utility-scale energy storage applications. In some cases, the applications require several thousand cells to meet the power and capacity requirements. Even such large systems do not require battery management systems at the cell level, being remarkably resilient to overcharging, without flammability and thermal runaway issues, and passing UL 9540A certification requirements without any protective measures being necessary. However, operation of these early deployments, indicate that to optimize systems performance and durability, energy management systems to manage overall systems charge-discharge protocols, taking the specific cell electrochemical characteristics, are desirable. The lessons learned and desirable innovations in designing and managing such large assemblies of cells will also be discussed.

Reversible Transformation of a Zinc Salt-Boosted High Areal Capacity Manganese Dioxide Cathode for Energy-Dense and Stable Aqueous Zinc Batteries

Recently, rechargeable aqueous zinc–manganese dioxide batteries have attracted extensive attention due to their intrinsic safety and high energy density. However, due to the poor reversibility and substrate-dependent feature of the MnO2 dissolution/deposition reaction, MnO2 is barely cycled at a low areal capacity and short period, which considerably limits its practical applications. Herein, a reversible transformation reaction of an inorganic salt Zn4(OH)6SO4·5H2O (ZHS) was coupled with the dissolution/deposition reaction of layered K- and Na-inserted MnO2 (KNMO) to realize a high areal capacity KNMO–ZHS composite cathode for energy-dense and stable aqueous zinc batteries. During the dissolution (discharging process) and deposition (charging process) of KNMO, ZHS transforms in the opposite direction and plays the role of a pH stabilizer during discharging and an in situ pore former during charging, thus considerably enhancing the reaction kinetics and reversibility of KNMO. The KNMO–ZHS cathode could deliver a high specific capacity of 335 mAh g–1 at 0.1 A g–1 and show stable cycling for 5000 cycles at 6 A g–1. In particular, for the first time, a zinc-ion battery with a record high mass loading of more than 50 mg cm–2 cathode was demonstrated and showed decent capacity retention, which paves the way for practical applications of zinc–manganese dioxide batteries.

Self-healable hydrogel electrolyte for dendrite-free and self-healable zinc-based aqueous batteries

The poor stability of zinc anodes caused by uneven deposition/stripping of zinc has inevitably limited the practical application of zinc-based aqueous batteries (ZABs). And the self-healing property is very necessary for improved lifespan and reliability of the flexible batteries under various deformations during their daily usage. In this work, a new self-healable hydrogel electrolyte (SHE) with rigid-flexible backbones is synthesized by cross-linking polymerization and composite strengthening. Owing to porous crosslinking network and more hydrophilic groups, the SHE possesses high ionic conductivity (23.1 mS/cm at 25 °C) and excellent mechanical strength, and the hydrophilic groups are conductive to improve interfacial compatibility between electrode and electrolyte, prompting much more disciplined Zn metal plating/stripping. And the dynamic hydrogen bonds derived from the hydroxyl groups of the polymer backbone can prompt self-healing and stretchable property of SHEs. As a result, the assembled flexible zinc-manganese dioxide batteries delivered a high capacity of 304 mAh g−1 at 0.5 A g−1 and good cycling stability with a capacity retention of 83.1% (vs. 62.5% with polyacrylamide) after 1500 charge/discharge cycles at 5.0 A g−1. Furthermore, the flexible batteries with SHEs can recover electrochemical performance with over 95% healing efficiency after 5 cycles of complete breaking/healing.

Highly conductive current collector for enhancing conductivity and power supply of flexible thin-film Zn–MnO2 battery

The present work optimizes factors to improve conductivity of carbon current collector for industrial application to flexible thin-film primary zinc-manganese dioxide battery. The investigated factors are ratio of carbon ingredients, current collector thickness, and silver coating. The performance of the zinc-manganese dioxide batteries assembling from the investigated current collectors were thoroughly analyzed with potentiostatic electrochemical impedance spectroscopy and galvanostatic discharge to understand the effect of these modifications for practical application. The cell impedance is mitigated when applying more fraction of the commercial carbon ‘A’, double thickness and silver coating. The discharge capacity of the battery is favored by carbon ‘A’ and silver coating. The results show the optimal design of the current collector determined as a 1:1 wt ratio of the commercial ‘C’ and ‘A’ carbon inks, a double thickness of carbon current collector and coating silver on the terminals. This design offers highly conductive current collectors and good discharge capacity for the flexible batteries. The investigation has promising findings for more advanced designs to manufacture flexible batteries.

Bromide–acetate co-mediated high-power density rechargeable aqueous zinc–manganese dioxide batteries

A new bromide-acetate co-mediated multicomponent metal-ion aqueous electrolyte was for the first time developed to achieve a high specific capacity two-electron transfer reaction between Mn2+ and MnO2 with extremely fast reaction kinetics.

Zincate-Blocking-Functionalized Polysulfone Separators for Secondary Zn-MnO2 Batteries.

Alkaline zinc-manganese dioxide (Zn-MnO2) batteries are well suited for grid storage applications because of their inherently safe, aqueous electrolyte and established materials supply chain, resulting in low production costs. With recent advances in the development of Cu/Bi-stabilized birnessite cathodes capable of the full 2-electron capacity equivalent of MnO2 (617 mA h/g), there is a need for selective separators that prevent zincate (Zn(OH)4)2- transport from the anode to the cathode during cycling, as this electrode system fails in the presence of dissolved zinc. Herein, we present the synthesis of N-butylimidazolium-functionalized polysulfone (NBI-PSU)-based separators and evaluate their ability to selectively transport hydroxide over zincate. We then examine their impact on the cycling of high depth of discharge Zn/(Cu/Bi-MnO2) batteries when inserted in between the cathode and anode. Initially, we establish our membranes' selectivity by performing zincate and hydroxide diffusion tests, showing a marked improvement in zincate-blocking (DZn (cm2/min): 0.17 ± 0.04 × 10-6 for 50-PSU, our most selective separator vs 2.0 ± 0.8 × 10-6 for Cellophane 350P00 and 5.7 ± 0.8 × 10-6 for Celgard 3501), while maintaining similar crossover rates for hydroxide (DOH (cm2/min): 9.4 ± 0.1 × 10-6 for 50-PSU vs 17 ± 0.5 × 10-6 for Cellophane 350P00 and 6.7 ± 0.6 × 10-6 for Celgard 3501). We then implement our membranes into cells and observe an improvement in cycle life over control cells containing only the commercial separators (cell lifetime extended from 21 to 79 cycles).

Gap width modification on fully screen-printed coplanar Zn|MnO2 batteries

Fully printed primary zinc-manganese dioxide (Zn|MnO2) batteries in coplanar configuration were fabricated by sequential screen printing. While electrode dimensions and transferred active masses were kept at constant levels, electrode separating gaps were incrementally enlarged from 1 mm to 5 mm. Calendering of solely zinc anodes increased interparticle contact of active material within the electrodes while the porosity of manganese dioxide based electrodes was maintained by non-calendering. Chronopotentiometry revealed areal capacities for coplanar batteries up to 2.8 mAh cm−2. Galvanostatic electrochemical impedance spectroscopy measurements and short circuit measurements were used to comprehensively characterise the effect of gap width extension on bulk electrolyte resistance and charge transfer resistance values. Linear relationships between nominal gap widths, short circuit currents and internal resistances were evidenced, but showed only minor impact on actual discharge capacities. The findings contradict previous assumptions to minimise gap widths of printed coplanar batteries to a sub-millimetre range in order to retain useful discharge capacities. The results presented in this study may facilitate process transfer of printed batteries to an industrial environment.

Amorphous manganese dioxide with the enhanced pseudocapacitive performance for aqueous rechargeable zinc-ion battery

Aqueous rechargeable zinc-manganese dioxide batteries have attracted extensive attention due to their high energy density, low cost, and environmental friendliness. However, the crystalline MnO2 polymorphs suffer from substantial phase changes upon cycling, leading to structural collapse and poor long-term cycling performance. Here, a highly reversible amorphous manganese dioxide with structural defects is reported as the cathode for aqueous rechargeable zinc-ion batteries (ARZIBs). Because of the existence of the abundant structural defects and intrinsic isotropic nature, the A-MnO2-δ exhibits significant pseudocapacitive contribution and facilitated reaction kinetics. As expected, the A-MnO2-δ delivers a high specific capacity of 301 mAh g−1 at 100 mA g−1 and long cycle-life with a capacity retention of 78% over 1000 cycles at 1 A g−1, which is better than its crystalline counterparts. In addition, a reversible H+ and Zn2+ two-step insertion storage mechanism of the A-MnO2-δ electrode is demonstrated. This study not only suggests that amorphous manganese dioxide can serve as a stable cathode for ARZIBs but also provides significant guidance to realize other high-capacity and long-lifespan aqueous batteries by using the amorphous materials.

Decoupling electrolytes towards stable and high-energy rechargeable aqueous zinc–manganese dioxide batteries

Aqueous battery systems feature high safety, but they usually suffer from low voltage and low energy density, restricting their applications in large-scale storage. Here, we propose an electrolyte-decoupling strategy to maximize the full potential of Zn–MnO2 batteries by simultaneously enabling the optimal redox chemistry of both the Zn and MnO2 electrodes. The decoupled Zn–MnO2 battery exhibits an open-circuit voltage of 2.83 V (in contrast to the typical voltage of 1.5 V in conventional Zn–MnO2 batteries), as well as cyclability with only 2% capacity fading after deep cycling for 200 h. Benefiting from the full utilization of MnO2, the Zn–MnO2 battery is also able to maintain approximately 100% of its capacity at various discharge current densities. We also demonstrate the feasibility of integrating the Zn–MnO2 battery with a wind and photovoltaic hybrid power generating system. This electrolyte-decoupling strategy is shown to be applicable for other high-performance zinc-based aqueous batteries such as Zn–Cu and Zn–Ag batteries. Low energy density and limited cyclability are preventing the commercialization of aqueous Zn–MnO2 batteries. Here, the authors combine the merits of operating Zn anodes in alkaline conditions and MnO2 cathodes in acidic conditions, via an electrolyte-decoupling strategy, to realize high-performance batteries.

Joint Charge Storage for High-Rate Aqueous Zinc-Manganese Dioxide Batteries.

Aqueous rechargeable zinc-manganese dioxide batteries show great promise for large-scale energy storage due to their use of environmentally friendly, abundant, and rechargeable Zn metal anodes and MnO2 cathodes. In the literature various intercalation and conversion reaction mechanisms in MnO2 have been reported, but it is not clear how these mechanisms can be simultaneously manipulated to improve the charge storage and transport properties. A systematical study to understand the charge storage mechanisms in a layered δ-MnO2 cathode is reported. An electrolyte-dependent reaction mechanism in δ-MnO2 is identified. Nondiffusion controlled Zn2+ intercalation in bulky δ-MnO2 and control of H+ conversion reaction pathways over a wide C-rate charge-discharge range facilitate high rate performance of the δ-MnO2 cathode without sacrificing the energy density in optimal electrolytes. The Zn-δ-MnO2 system delivers a discharge capacity of 136.9 mAh g-1 at 20 C and capacity retention of 93% over 4000 cycles with this joint charge storage mechanism. This study opens a new gateway for the design of high-rate electrode materials by manipulating the effective redox reactions in electrode materials for rechargeable batteries.

Failure Analysis of the Rechargeable Porous Zinc Electrode in Alkaline Electrolyte

Metallic zinc (Zn) is an attractive negative electrode material for rechargeable batteries because it is a non-toxic, earth abundant metal. It has a low equilibrium potential of -1.35 V vs. mercury-mercuric oxide (Hg|HgO) in concentrated alkaline electrolyte, a high gravimetric discharge capacity of 820 mAh/g, and a high volumetric discharge capacity of 5850 mAh/mL. During discharge, Zn oxidizes and forms a dissolved complex known as the zincate ion, Zn(OH)4 2-, from which zinc oxide (ZnO) precipitates as a solid. On charge, Zn(OH)4 2- is reduced to metallic Zn. Motivation to study the Zn electrode in rechargeable batteries is driven by a target overall battery energy density of 200 Wh/L that is sustainable for 500 or more charge-discharge cycles. This corresponds to a Zn electrode volumetric capacity of 650 mAh/mL. The cycle life of the porous Zn electrode in concentrated alkaline electrolyte is observed to decrease with increasing percentage of discharge capacity of Zn accessed. The percentage of discharge capacity of Zn accessed is known as the depth of discharge (DOD). Zn electrodes were cycled in the range of 1% to 15% Zn DOD in zinc-manganese dioxide (Zn-MnO2) batteries and in the range of 15% to 30% Zn DOD for zinc-nickel (Zn-Ni) batteries. Additives were incorporated into the zinc electrodes for the tests done on Zn-Ni batteries. Additives used were surfactant cetyltrimethylammonium bromide (CTAB), bismuth oxide (Bi2O3), synthetic layered silicate Laponite, and calcium hydroxide (Ca(OH)2). The potential values of the Zn electrodes vs. Hg|HgO reference electrodes were recorded. During healthy galvanostatic discharge, Zn electrodes displayed a nearly constant potential vs. Hg|HgO at approximately -1.35 V. Tests that failed due to Zn exhibited a shift from this equilibrium potential that corresponded to a loss of cell voltage. This shift may be attributed to a concentration overpotential as ZnO is precipitated, thereby inhibiting the hydroxide ions from reaching the reacting metal interface. The shift may also be due to formation of a passivated layer on the electrode which effectively blocks the remaining active material. There are multiple regimes observed in the potential curves of the Zn electrode vs. Hg|HgO prior to cell failure. Beyond the healthy plateau at -1.35 V, a sloping potential is observed. This is followed by an additional plateau. The second plateau shifts with increasing cycle number and precedes cell death. See the attached figure for discharge curves of a Zn electrode cycled at 11.3% Zn DOD. After the second plateau a steep slope is observed in the potential for later cycles, which is believed to be due to passivation of the Zn electrode. The additives were observed to modify the discharge potential curve of the Zn electrode vs. Hg|HgO. Figure 1