Mn Dissolution Research Articles

Synthesis of Trisiloxane with the Dioxaborolane Group as a Cathode Film-Forming Electrolyte Additive for High-Temperature LiMn2O4/Li4Ti5O12 Batteries.

LiMn2O4 batteries have been widely applied as various portable electronic devices and electric vehicles owing to the merits of low cost, high operating voltage, excellent rate capability, and environmental friendliness. However, the poor performance at elevated temperatures remains a serious technical challenge in terms of commercial application purposes. A borate-containing trisiloxane compound of TSMBO is designed and synthesized as a cathode film-forming electrolyte additive to improve the electrochemical performances of LiMn2O4/Li4Ti5O12 batteries, especially at high temperatures of 55 °C. Atomic force microscopy measurement confirms that the trisiloxane moiety in TSMBO can construct a cathode electrolyte interface (CEI) with higher mechanical strength and better flatness compared to the disiloxane moiety in the TSMBO analogue with a similar chemical structure. The robust CEI film on the surface of the LiMn2O4 cathode and the inhibited hydrolysis of LiPF6 in the electrolyte significantly suppress the dissolution of Mn from the LiMn2O4 cathode and maintain the structural integrity of the LiMn2O4 lattice over cycling. Thus, the LiMn2O4/Li4Ti5O12 coin cell using the TSMBO-containing electrolyte with an optimized addition level of 0.5 wt % exhibits a higher capacity retention of 49.3% compared with 34.3% for the baseline electrolyte after 300 cycles under 1C rate at 55 °C. The LiMn2O4/Li4Ti5O12 pouch cell tests show excellent high-temperature and cycling performance at 55 °C and a higher capacity retention of 90.4% after 500 cycles at 2C compared to 79.7% for that with the baseline electrolyte after 430 cycles at 2C. This work demonstrates that TSMBO is a promising electrolyte additive for practical use to improve the cycling stability of LiMn2O4/Li4Ti5O12 batteries at elevated temperatures.

Dissolution of metals in NCM622 cathode through the Dissimilatory process with Na-lactate by Shewanella putrefaciens

Objectives:The objective of this study is to confirm the possibility of reduction and consequent dissolution of Li, Ni, Co, and Mn from NCM622 cathodes in spent Li-ion batteries through the anaerobic respiration with Na-lactate by Shewanella putrefaciens.Methods:The method involves using anaerobic microbial respiration to mimic dissimilatory metal oxide reduction, allowing metals to be leached from NCM622 cathodes (LiNi0.6Co0.2Mn0.2O2) under near-neutral pH conditions (~7.5).Results and Discussion:The results show that approximately 26 wt% of the total Li, Ni, Co, and Mn were successfully leached into the solution within two weeks. This approach differs significantly from conventional acidic leaching processes, offering a more environmentally friendly and sustainable alternative. In addition, we provide quantitative information regarding the dissolution of NCM622 when it is exposed in environmental systems.Conclusion:In conclusion, microbial-based metal leaching presents a novel, sustainable pathway for recovering metals from spent Li-ion batteries, addressing environmental concerns and reducing dependence on traditional energy-intensive recovery methods.

Dextran Sulfate Sodium as Multifunctional Aqueous Binder Stabilizes Spinel LiMn2O4 for Lithium Ion Batteries

AbstractSpinel LiMn2O4 (LMO) has several beneficial properties for utilization as a cathode material for lithium‐ion batteries, including a high operating voltage, thermal stability, low cost, and eco‐friendliness. However, its application is limited by capacity fading due to structural transformation and manganese dissolution upon cycling. A method is proposed to resolve these two issues, using dextran sulfate sodium (DSS) as an aqueous binder to coat the LMO surface. DSS stabilizes the surface/interface structure of LMO by incorporating Na into the interstitial 16c sites, creating a uniform surface coating layer and promoting the formation of a homogeneous and stable cathode‐electrolyte interphase derived from the sulfate groups in DSS and enriched with LiF/LiSOxF. The aqueous DSS binder effectively suppresses the surface degradation and Mn dissolution of spinel LMO. The LMO electrode based on DSS exhibits superior cycling stability and rate performance compared with those of electrodes using the conventional poly(vinylidene difluoride) binder. These findings demonstrate the potential value of DSS as a multifunctional aqueous binder in stabilizing spinel LMO for lithium‐ion batteries.

Optimizing the crystal structure and electrochemical properties of Na4MnCr(PO4)3 by trace La doping

Na4MnCr(PO4)3, a manganese-based NASICON-type phosphate cathode material, is attracted considerable attention due to its high voltage and energy density. However, its practical application is hindered by poor electronic conductivity and inferior sodium ion diffusion kinetics. In this study, trace La3+ is utilized to optimize the lattice structure of Na4MnCr(PO4)3 due to its unique energy level structure. La3+ doping significantly enhances the local environment of the Mn-O bond and stabilizes the lattice structure by improving covalency, thereby mitigating Mn dissolution during charge–discharge cycles. Additionally, the large ionic radius of La3+ promotes the sodium ion transport kinetics by expanding the cell volume and facilitating rapid sodium storage. As a result, the optimal Na4MnCr0.995La0.005(PO4)3/C sample demonstrates an impressive initial discharge specific capacity of 124.5 mAh g−1 at 0.1C and superior cycling stability with a capacity retention of 70.2 % after 500 cycles at 5C. Furthermore, density functional theory calculations indicate that La3+ doping can enhance conductivity and reduce the energy barrier for sodium ion diffusion. This study presents an effective and cost-efficient doping strategy for modifying high-energy density NASICON-type phosphate cathode materials, showing promising potential in the field of sodium ion batteries.

Boosting the synergistic activation of δ-MnO2 as cathode for aqueous zinc-ion batteries through Ni, Co co-doping

Layered δ-MnO2 is regarded as a promising cathode material for high-performance aqueous zinc-ion batteries (AZIBs) due to the sufficient interlayer spacing for the accommodation and migration of charge carriers. However, the sluggish activation process limits the reversible capacity, thus prevent their application. In this study, Ni-Co co-doped layered δ-MnO2 was designed to enhance ion diffusion capability and cycling stability. The influencing mechanism of Ni and Co on the long activation process are proposed by a comparative analysis between single doping and co-doping approaches. Specifically, the optimized co-doped δ-MnO2 maintained a high specific capacity of 200.2 mAh·g−1 with a capacity retention of 97.40 % after 700 cycles at 1 A·g−1. The co-doping approach exhibited a synergistic effect in suppressing Mn dissolution and enhancing ion diffusion capability. These findings provide new directions on boosting the synergistic activation process of manganese oxide and shed lights on the rational design of low-cost and high-safe batteries.

Effects of Dynamic Surface Transformation on the Activity and Stability of Mixed Co‐Mn Cubic Spinel Oxides in the Oxygen Evolution Reaction in Alkaline Media

AbstractAn atomic‐scale understanding of how electrocatalyst surfaces reconstruct and transform during electrocatalytic reactions is essential for optimizing their activity and longevity. This is particularly important for the oxygen evolution reaction (OER), where dynamic and substantial structural and compositional changes occur during the reaction. Herein, a multimodal method is developed by combining X‐ray fine structure absorption and photoemission spectroscopy, transmission electron microscopy, and atom probe tomography with electrochemical measurements to interrogate the temporal evolution of oxidation states, atom coordination, structure, and composition on Co2MnO4 and CoMn2O4 cubic spinel nanoparticle surfaces upon OER cycling in alkaline media. Co2MnO4 is activated at the onset of OER due to the formation of ≈2 nm Co‐Mn oxyhydroxides with an optimal Co/Mn ratio of ≈3. As OER proceeds, Mn dissolution and redeposition occur for the CoMn oxyhydroxides, extending the OER stability of Co2MnO4. Such dynamic dissolution and redeposition are also observed for CoMn2O4, leading to the formation of less OER‐active Mn‐rich oxides on the nanoparticle surfaces. This study provides mechanistic insights into how dynamic surface reconstruction and transformation affect the activity and stability of mixed CoMn cubic spinels toward OER.

Cation/Anion Doping Strategy for Na4MnV(PO4)3 with High Energy Density and Long Cycling Life through Construction by Aspergillus niger.

Na4MnV(PO4)3 (NMVP) has gained attention for its high redox potential, good cycling stability, and competitive price but suffers from poor intrinsic electronic conductivity and Jahn-Teller effect from Mn3+. In this work, cation/anion doping strategy was used for Aspergillus niger-bioderived carbon-coated NMVP (NMVP/AN) to improve the structural stability and electrochemical performance, where Al3+ doping inhibited the dissolution of Mn and enhanced the Mn3+/Mn2+ redox pair activity; besides, F- doping not only weakens the Na2-O bond but also endows the hierarchical and porous structure of NMVP/AN, which led to a more rapid and fluid transfer of Na+. The elaborately designed Na3.9Mn0.9Al0.1V(PO4)3/AN (NMAVP/AN) exhibits 105.9 mA h g-1 at 0.5 C, and the as-prepared Na3.1MnV(PO3.7F0.3)3/AN (NMVPF/AN) delivers 104.1 mA h g-1 at 5 C. Further demonstration of the hard carbon//NMAVP/AN full cell manifests the good potential of Al3+-doped NMVP/AN for practical applications (100.6 mA h g-1 at 1 C). These findings open up the possibility of unlocking the high-performance Na superionic conductor (NASICON).

A stable ZnMn2O4 cathode for aqueous Zn-ion batteries via Ni doping to suppress Mn dissolution

ZnMn2O4 (ZMO) emerges as a promising cathode for aqueous Zn-ion batteries due to its high theoretical capacity of 224 mAh g−1 and operating voltage of ∼1.9 V (vs. Zn2+/Zn). However, it suffers from capacity degradation over cycling, attributed to the dissolution of redox-active Mn through Mn3+ disproportionation. In this study, we propose a strategy to stabilize ZMO cathodes by transforming Mn3+ into Mn4+ via Ni doping, aiming for charge balance. The ZnMn2−xNixO4 (x = 0, 0.5, 1.0, and 1.5) with different Ni amounts was prepared by straightforward precipitation and calcination. The mitigation of redox-active Mn dissolution enhanced the specific capacity of all Ni-doped ZMO compared to 201 mAh g−1 of ZMO. ZnMn1.5Ni0.5O4 and ZnMnNiO4 exhibit 277 and 278 mAh g−1, respectively, surpassing ZMO’s theoretical capacity (224 mAh g−1) of ZMO. This additional capacity was attributed to MnOx deposition on the cathode and the charge storage reaction with Zn-ion within the MnOx deposit. Furthermore, Ni doping induces a structural transition of the tetragonal into a cubic spinel, expanding the unit cell volume. This structural modification combined with suppressed Mn dissolution contributes to improved cycling stability. ZnMnNiO4 exhibits 80 % retention of initial capacity after 1000 cycles, outperforming ZMO (57 % retention). The expanded unit cell reduces repulsion between inserted Zn ions, enabling a higher rate performance than pure ZMO. The change in Mn valence states induced by Ni doping enhanced the lifespan and rate capability of ZMO cathodes, underscoring their potential as cathodes for Zn-ion batteries.

Reductive Dissolution of NCM Cathode through Anaerobic Respiration by Shewanella putrefaciens.

The consumption of lithium-ion batteries (LIBs) has considerably increased over the past decade, leading to a rapid increase in the number of spent LIBs. Exposing spent LIBs to the environment can cause serious environmental harm; however, there is a lack of experimentally obtained information regarding the environmental impacts of abandoned cathode materials. Here, we report the interactions between Shewanella putrefaciens, a microorganism commonly found in diverse low-oxygen natural settings, and LiNi0.6Co0.2Mn0.2O2 (NCM622) under anaerobic conditions. We present compelling evidence that the anaerobic respiration of Shewanella putrefaciens triggers ∼59 and ∼78% dissolution of 0.2 g/L pristine and spent NCM622, respectively. We observed that Shewanella putrefaciens interacted with the pristine and the spent NCM622 under anaerobic conditions at a neutral pH and room temperature and induced the reduction of Ni, Co, and Mn, resulting in the subsequent dissolution of Li, Ni, Co, and Mn. Moreover, we found that secondary mineralization occurred on the surface of reacted NCM622. These findings not only shed light on the substantial impact of microbial respiration on the fate of discarded cathode materials in anaerobic environments but also reveal the potential for sustainable bioleaching of cathodes in spent LIBs.

Mechano‐Electrochemical Behavior of Nanostructured Li‐ and Mn‐Rich Layered Oxides with Superior Capacity Retention and Voltage Decay for Sulfide‐Based All‐Solid‐State Batteries

AbstractLi‐ and Mn‐rich layered oxides (LMROs) are recognized as promising cathode materials for lithium‐ion batteries (LIBs) due to their high specific capacity and cost efficiency. However, LMROs encounter challenges such as manganese dissolution in electrolytes and the release of oxygen gas from irreversible oxygen redox reactions, leading to structural degradation and voltage decay that reduce energy density. Consequently, recent research has shifted toward employing LMROs in all‐solid‐state batteries (ASSBs), where Mn dissolution is negligible. Herein, nanostructured LMROs demonstrate superior electrochemical compatibility with sulfide‐based solid electrolytes in ASSBs compared to conventional LIBs. Nanostructured LMRO exhibits outstanding capacity retention (97.1% after 1300 cycles at 30 °C) with significantly suppressed voltage decay. Furthermore, the initial electrochemical activation of Li2MnO3 domains within LMRO is explored in terms of the mechano‐electrochemical interactions in the composite cathode. At elevated temperatures, interfacial degradation accelerates due to the chemical oxidation of Li6PS5Cl solid electrolytes, driven by oxygen released from LMRO. To address this, LMRO surfaces are modified with thioglycolic acid through esterification, suppressing interfacial degradation of Li6PS5Cl and ensuring stable capacity retention over 500 cycles at 60 °C. These findings underscore the potential of LMRO materials as promising cathode options for ASSBs, surpassing those used in LIBs.

Regulating the Manganese Valence State Improves the Kinetic Properties of Manganese‐Based Cathodes

AbstractManganese (Mn)‐based lithium (Li)‐ion batteries with high energy density and low cost have recently attracted considerable attention. One drawback of Mn‐based batteries is the severe capacity attenuation caused by the Jahn‐Teller effect, which distorts the crystal structure and reduces the kinetics of Li‐ion insertion/extraction in the cathodes. In this study, the Mn valence state is regulated on the surface of Mn‐based oxide particles and oxygen vacancies are introduced to facilitate rapid Li‐ion transport and charge storage by adding succinonitrile (SN) to Mn‐based cathodes. Because of the reaction between SN and Mn‐based cathode particles, the contents of Mn3+ ions and oxygen vacancies increase, leading to an improvement in the Li‐ion kinetic properties of the cathodes as well as a reduction in the dissolution of Mn from the cathodes. By regulating the Mn valence state, Li‐ion and Li metal batteries with LiMn2O4 or Li‐rich Mn‐based layered oxide cathodes show significantly enhanced discharge capacity and improved cyclic performance. This study demonstrates that regulating the valence state of Mn ions is an effective strategy for enhancing the electrochemical performance of Mn‐based Li batteries and that adding SN to the cathodes is a cost‐effective method for mass production.

Surface Reconstruction Enhanced Li-Rich Cathode Materials for Durable Lithium-Ion Batteries.

Regulating the distribution of surface elements in lithium-rich cathode materials can effectively change the electrochemical performance of cathode materials. Considering that the enrichment of Mn element on the surface is the main reason for the irreversible phase transition and dissolution of its surface structure, which in turn is the main reason for performance degradation. Based on the molten salt-assisted sintering method, a lithium rich cathode material with surface rich Ni and Co is designed and prepared. The surface enrichment of Ni and Co effectively reduces the dissolution of Mn, promotes the occurrence of irreversible collapse of surface structure from layered phase to rock salt phase on the material surface, improves the stability of surface crystal phase structure, and improves the cycling stability of positive electrode materials. Notably, after 500 cycles at 1 C current density, the discharge-specific capacity attained 189.8 mAh g -1, with a capacity retention rate of 88.9%, indicating a 42.1% improvement in capacity retention. Molten salt treatment is widely used in the modification of positive electrode materials. The research work will provide new ideas for improving the stability of lithium rich materials and promoting their commercial applications.

Anoxic Manganese Bioleaching – Investigation of Scale-up Parameters in a Stirred Bioreactor

Presently huge operation costs arising from aeration and high electron donor requirements accompanied by low metal recovery rates are some impediments to the large-scale application of bioleaching for low-grade ores. The current study investigates key parameters for scaling up anoxic bioleaching, which overcomes some of the above shortcomings, on polymetallic manganese nodules using soil-based manganese-reducing bacterial consortia in a stirred bioreactor. Operating conditions such as carbon source concentration and pulp density were optimized. Parameters like pH, oxidation–reduction potential (ORP), and microbial growth were monitored in the bioreactor in both stirred and non-stirred conditions. The Mn(IV) reduction and dissolution in the bioreactor was 27 (±2.8)% over 30 days, which significantly enhanced to 43 (±1.5)% and 42 (±0.35)% in the presence of humic acid and anthraquinone sulfonic acid, respectively, in 15 days. A maximum dissolution of 21 (±4.1)% Cu, 10 (±3.0)% Ni, 18 (±4.7)% Co and 7 (±3.9)% Fe were also obtained with 100 µM humic acid from the agitated bioreactor in 15 days. The corresponding specific glucose consumption rate per unit mass of ore was found to be 27 mg g−1 day−1, which is 10 times lower than the rates reported previously for aerobic bioleaching methods. The investigation shows that mild agitation can significantly improve the anoxic bioleaching, especially with added electron shuttles, to enable better ore-bacteria interaction and prevent ore compaction during scale-up. The pH and ORP of the system point toward a reductive dissolution of Mn by the organisms.

Tailoring MnO2 Cathode Interface via Organic–Inorganic Hybridization Engineering for Ultra‐Stable Aqueous Zinc‐Ion Batteries

AbstractManganese (Mn)‐based aqueous zinc ion batteries show great promise for large‐scale energy storage due to their high capacity, environmental friendliness, and low cost. However, they suffer from the severe capacity decay associated with the dissolution of Mn from the cathode/electrolyte interface. In this study, theoretical modeling inspires that the amino acid molecule, isoleucine (Ile), can be an ideal surface coating material for α‐MnO2 to stabilize the surface Mn lattice and mitigate Mn dissolution, thereby enhancing cycling stability. Furthermore, the coated Ile molecular layers can accumulate Zn2+ ions from the electrolyte and promote those ions’ transport to the α‐MnO2 cathode while prohibiting H2O from accessing the α‐MnO2 surface, reducing the surface erosion. The compact organic–inorganic interface is experimentally synthesized for α‐MnO2 utilizing Ile that shows homogeneous distribution on the well‐defined Ile‐α‐MnO2 nanorod electrodes. The fabricated aqueous zinc‐ion battery exhibits a high specific capacity (332.8 mAh g−1 at 0.1 A g−1) and excellent cycling stability (85% after 2000 cycles at 1 A g−1) as well as good inhibition toward Mn2+ dissolution, surpassing most reported cathode materials. This organic–inorganic hybrid interface design provides a new, simple avenue for developing high‐performance and low‐cost Mn‐based aqueous zinc ion batteries (AZIBs).

Electrochemically induced interface by LiBOB to enhance cycling performance of LiFe0.4Mn0.6PO4 cathode for lithium-ion batteries

Olivine-type lithium iron manganese phosphate (LFMP) combines the high energy density of LiMnPO4 with the high safety of LiFePO4, is considered to be one of the most promising cathode materials for the next generation. However, the Mn dissolution behavior due to the Jahn-Teller effect of Mn3+ irreversibly causes loss of active material during electrochemical cycling, accompanied by severe capacity decay and structural degradation, which is more severe at elevated temperature. Herein, in order to enhance the cycling performance of LFMP cathode material, the cathode-electrolyte interface is stabilized by inducing bis(oxalate)borate (LiBOB) decomposition electrochemically to form a CEI layer. Specifically, the capacity retention of the battery in the electrolyte containing 0.75 wt% LiBOB is 95.37 % after 200 cycles at 25 °C and 1C. (1C = 170 mA g−1) The capacity retention is 89.17 % after 200 cycles at 55 °C and 1C, compared to only 72 % in the electrolyte without LiBOB. The superior cycling performance is attributed to the formation of a uniform CEI layer induced by LiBOB electrochemically, which inhibits the parasitic reaction between the cathode and electrolyte, reduces the dissolution of Mn in the active substance, enabling superior and safer cycling performance even at elevated temperature.

Se‐dopant Modulated Selective Co‐Insertion of H+ and Zn2+ in MnO2 for High‐Capacity and Durable Aqueous Zn‐Ion Batteries

AbstractMnO2 is commonly used as the cathode material for aqueous zinc‐ion batteries (AZIBs). The strong Coulombic interaction between Zn ions and the MnO2 lattice causes significant lattice distortion and, combined with the Jahn–Teller effect, results in Mn2+ dissolution and structural collapse. While proton intercalation can reduce lattice distortion, it changes the electrolyte pH, producing chemically inert byproducts. These issues greatly affect the reversibility of Zn2+ intercalation/extraction, leading to significant capacity degradation of MnO2. Herein, we propose a novel method to enhance the cycling stability of δ‐MnO2 through selenium doping (Se−MnO2). Our work indicates that varying the selenium doping content can regulate the intercalation ratio of H+ in MnO2, thereby suppressing the formation of ZnMn2O4 by‐products. Se doping mitigates the lattice strain of MnO2 during Zn2+ intercalation/deintercalation by reducing Mn−O octahedral distortion, modifying Mn−O bond length upon Zn2+ insertion, and alleviating Mn dissolution caused by the Jahn–Teller effect. The optimized Se−MnO2 (Se concentration of 0.8 at.%) deposited on carbon nanotube demonstrates a notable capacity of 386 mAh g−1 at 0.1 A g−1, with exceptional long‐term cycle stability, retaining 102 mAh g−1 capacity after 5000 cycles at 3.0 A g−1.

External short circuit of lithium-ion battery after high temperature aging

The microscopic and macroscopic changes of lithium-ion batteries after high temperature cycling and their effect on external short circuit (ESC) are studied in this study. The results indicate that solid electrolyte interphase and cathode electrolyte interphase cover the surface of anode and cathode. Transition metal, Mn is dissolved from the cathode. Capacity and resistance decreases and increases after cycling at high temperature. The safety of batteries after ESC is ranked as: 70 % state of health (SOH) > 100 % SOH > 80 % SOH > 90 % SOH. Thermal runaway only occurs to battery with 90 % SOH after ESC. Increase of resistance after cycling affects heat generation during ESC less. Onset temperature and thermal runaway temperature increases and decreases owing to solid electrolyte interphase growth and Mn dissolution. Compared to fresh battery, safety of battery with 70 % SOH after ESC increases. Fast discharging causes side reactions for aged batteries, which also generate heat. The heat generation effect of fast discharging decreases with the decrease of SOH after 90 % SOH. Local micro internal short circuit causes more heat generation for aged batteries. The results are important for safety control of lithium-ion battery.

Mitigating Jahn–Teller effect of MnO2 via charge regulation of Mn-local environment for advanced calcium storage

Manganese dioxide (MnO2) stands out as a prospective cathode material for calcium ion batteries (CIBs) owing to its elevated theoretical capacity and high operating voltage. Nevertheless, MnO2 with Jahn-Teller (J-T) twisted MnO6 octahedra experiences severe Mn dissolution during cycling, leading to the destabilization of the transition metal layer and resulting in poor cycling performance. In this work, Mo-substitution is purposely proposed to suppress the J-T effect in MnO2 for CIBs. The local charge of Mn is regulated by Mo doping, which enhances the electrical conductivity of MnO2 and suppresses the J-T distortion of the MnO6 octahedron. Meanwhile, density-functional theory (DFT) calculations manifest that Mo doping enhances the structural integrity of MnO2, making it difficult for Mn to escape from the MnO6 structure and inhibiting the dissolution of Mn. Accordingly, Mo-MnO2 demonstrates impressive rate capability (112 mAh g−1 at 1 A g−1) and excellent cycling stability, maintaining approximately 93.9 % capacity after 900 cycles at 1 A g−1. As a result, the introduction of heteroatoms through doping offers a novel design approach for the advancement of cathode materials for advanced CIBs.

Seed-Assisted Reversible Dissolution/Deposition of MnO2 for Long-Cyclic and Green Aqueous Zinc-Ion Batteries.

Manganese oxide (MnO2) based aqueous zinc-ion batteries (AZIBs) are considered to be a promising battery for grid-scale energy storage. However, they usually suffer from the great challenge of capacity attenuation due to Mn dissolution and irreversible structural transformation. Herein, full use of the shortcomings is made to design high-performance cathode-free AZIBs. Manganese-based Prussian blue analog (Mn-PBA) is selected as a seed layer to provide a stable MnO2 electrodeposition surface. Thanks to the large specific surface area and manganophilic nature of Mn-PBA, the deposition/dissolution kinetics between Mn2+ and MnO2 are significantly enhanced. Systematic studies revealed the mechanism of MnO2 deposition-dissolution related to the reversible transformation of manganese oxide hydroxide and zinc hydroxide sulfate hydrate. Based on this, the developed cathode-free AZIBs exhibit outstanding rate performance (with a specific capacity of 273.7 mAh g-1 at 1 A g-1) and extraordinary cycle stability (maintaining a specific capacity of 52.3 mAh g-1 after 50000 cycles at 20 A g-1). Furthermore, the AZIBs with non-toxic, biocompatible materials can be directly discarded after use, without causing pollution to the environment, which is expected to help achieve the sustainable development goals.

In Situ Electron Paramagnetic Resonance Reveals Fading Mechanism of Mn-Based Prussian Blue Analogue: Accelerated Mn Dissolution Due to Charge Delocalization

In Situ Electron Paramagnetic Resonance Reveals Fading Mechanism of Mn-Based Prussian Blue Analogue: Accelerated Mn Dissolution Due to Charge Delocalization