Remarkable Capacity Retention Research Articles

Profiting the Co-Modifications of Li2SnO3 Coating and Sn4+ Doping in Co-Free Ni-Rich Cathode Particles for Lithium-Ion Batteries

Layered oxides with high nickel content are advanced cathode materials for high-energy-density lithium-ion batteries but still suffer from severe voltage decay and cycling instability. Herein, a nano-Li2SnO3 coating and Sn4+-doping co-stabilized Co-free LiNi0.8Mn0.2O2 (NM-82) cathodes were synthesized through the adsorption of tin dioxide sol, followed by high-temperature calcination. Profiting from co-benefits, the electrochemical reversibility and rate capability of the NM-82 electrode have been significantly improved. Herein, the NM-82 electrode modified with 2 wt % Li2SnO3 (NM@Sn-2) achieves the largest specific capacity with remarkable capacity retention. The enhanced cycle stability is also revealed in the graphite/NM@Sn-2 soft pack battery, which features a reversible capacity of 173.20 mA h g–1 and a high capacity retention of 90.54%, outperforming those of the NM-82 cathode (154.09 mA h g–1 and 81.23%) at 0.2 C after 300 cycles. The improved performance of the NM@Sn-2 cathode originates from its stronger structure, lower Li/Ni cation mixing degree, and faster Li+ kinetics, also verified by theoretical calculations. Therefore, the one-step construction of nano-Li2SnO3 coating coupling with Sn4+ doping strategy shows a promising strategy to mitigate the capacity deterioration of the Co-free Ni-rich layered oxides.

Microwave-Assisted Hierarchically Grown Flake-like NiCo Layered Double Hydroxide Nanosheets on Transitioned Polystyrene towards Triboelectricity-Driven Self-Charging Hybrid Supercapacitors.

Recently, there is a need to explore the utilization of various heterostructures using the designed nanocomposites and tuning the surfaces of electrodes for improving the electrochemical performance of supercapacitors (SC). In this work, a novel approach is successfully employed through a facile two-step synthetic route with the assistance of a microwave for only 1 min. Depending on the glass transition of a polystyrene (PS) substrate and electrochemical deposition (ECD) of electroactive Ni-Co layered double hydroxides (LDHs), a hierarchically designed flake-like morphology can be readily prepared to enhance the surface-active sites, which allows a rhombohedral Ni-Co LDHs electrode to obtain superior electrochemical properties. Further, the interactions between electrode and electrolyte during the diffusion of ions are highly simplified using multiple enhanced electroactive sites and shorter pathways for electron transfer. The unique surface architecture of the PS substrate and the synergistic effect of the bimetallic components in Ni-Co LDHs enable this substrate to obtain desired electrochemical activity in charge storage systems. The optimized MWC Co0.5Ni0.5 electrode exhibited an areal capacity of 100 µAh/cm2 at a current density of 1 mA/cm2 and a remarkable capacity retention of 91.2% over 5000 continuous charging and discharging cycles due to its remarkable synergistic effect of abundant faradaic redox reaction kinetics. The HSC device is assembled with the combination of optimized MWC Co0.5Ni0.5 and activated carbon as a positive and negative electrode, respectively. Further, the electrochemical test results demonstrated that MWC Co0.5Ni0.5 //AC HSC device showed a high areal capacitance of 531.25 mF/cm2 at a current density of 5 mA/cm2. In addition, the fabricated an aqueous HSC device showed a power density of 16 mW/cm2 at an energy density of 0.058 mWh/cm2, along with the remarkable capacity retention of 82.8% even after 10,000 continuous charging and discharging cycles. Moreover, the assembled hybrid supercapacitor (HSC) device is integrated with a triboelectric nanogenerator (TENG) for the development of energy conversion and storage systems. Not only an extensive survey of materials but also an innovative solution for recent progress can confirm the wide range of potential SC applications. Remarkably, this study is a new way of constructing self-powered energy storage systems in the field of sustainable wearable electronics and future smart sensing systems.

Realizing high reversibility and safety of Zn anode via binary mixture of organic solvents

The conventional aqueous electrolyte in Zn batteries often induces a chain of interconnected marvels including dendrites, passivation and hydrogen evolution leading to catastrophic battery failures. Herein, we propose a new organic electrolyte comprising of mixed solvents {trimethyl phosphate (TMP), N-methyl formamide (NMF)} and Zn(OTf)2 salt, which not only enables highly reversible and dendrite-free Zn anode but ensures excellent non-flammability endorsing battery safety. The enhanced electrolyte-electrode (Zn) interactions and changes in solvation structure of electrolyte due to NMF incorporation in TMP, assisted uniform Zn deposition free from dendrites. Consequently, Zn anode exhibited long cycling of over 1200 h at high current densities of 3.0 and 5.0 mA cm−2 with high average Coulombic efficiency (CE）99.83% and affords promising areal capacity of 20.0 mAh cm−2. Much stronger TMPNMF-Zn2+ and NMF-Zn surface interactions revealed by molecular simulations provided insights to the beneficial role of NMF as co-solvent in stabilizing Zn anode. Moreover, Zn/NaV3O8 full battery delivered remarkable capacity retention and cycling stability in TMPNMF electrolyte. The present research work proposes promising route for designing new electrolyte systems for sustainable and safe non-aqueous Zn batteries.

From waste to resources: transforming olive leaves to hard carbon as sustainable and versatile electrode material for Li/Na-ion batteries and supercapacitors

Over the last few years, biomass-derived hard carbon materials are drawing more and more attention because of their high abundance, cost breakdown, high performance, and fast regeneration. In this context, the synthesis of hard carbon from olive leaves, a widely available by-product of table olive and olive oil industries, is here reported and its performance, as a sustainable electrode material for Li-ion batteries (LIBs), Na-ion batteries (NIBs), and supercapacitors (SCs), are evaluated. According to the information acquired by structural characterization, a disordered structure is confirmed for the synthesized hard carbon. When tested as anode for LIBs and NIBs, electrodes based on Na-CMC green binder show discharge capacities of 331.0 mAh/g and 265.4 mAh/g at 1C (with minor irreversibility), respectively, with promising cycling stability. In SC application, the electrode delivers a high specific capacitance of 169.6 F/g at 0.5 A/g and remarkable capacity retention of 96.7% after more than 20,000 cycles at 10 A/g. As a result, this work confirms the possibility to use olive leaves-derived hard carbon material for the low-cost, environmental-friendly fabrication of electrodes with high energy and power capabilities.

Heterostructured Li3VO4-Ga2O3-embedded porous carbon nanofibers as advanced anode materials for lithium-ion batteries.

The development of lithium-ion batteries (LIBs) is still facing challenges due to the design and optimization of anode materials and their Li-ion storage mechanisms. In this study, we aimed to address this issue by constructing three-dimensional hierarchical heterojunction structures using a double needle electrospinning strategy. The heterostructure was composed of insertion-type Li3VO4 and conversion/alloying-type Ga2O3 embedded porous carbon nanofibers (Li3VO4-Ga2O3@PCNF). The designed heterostructured Ga2O3 and Li3VO4 materials were found to effectively enhance charge transfer dynamics, thereby improving capacity and rate capability. Additionally, the facilitated efficient contact between the electrode and electrolyte, enabling the diffusion of ions and electrons. When applied as an anode material in LIBs, the Li3VO4-Ga2O3@PCNF composite achieved a high capacity of 630.0 mA h g-1 at 0.5 A g-1, and full capacity recovery after 6 periods of rate testing over 480 cycles. When simulating the practical application under a high discharge current of 6.0 A g-1, the Li3VO4-Ga2O3@PCNF could still deliver a high discharge capacity of 322.0 mA h g-1 after 2000 cycles. Furthermore, the composite exhibited a remarkable capacity retention of 77.2% after 2000 cycles at 6.0 A g-1. This research provides valuable guidance for the design of high-performance Li3VO4-based anodes, particularly in addressing the issue of inferior electronic conductivity.

Weakly solvated EC-free linear alkyl carbonate electrolytes for Ni-rich cathode in rechargeable lithium battery.

Ethylene carbonate (EC) in the electrolyte is not stable in cells operated at highvoltage (≥4.4V) or with Li metal anode, which greatly reduce the energy density and lifetime of the rechargeable lithium battery. Herein, an EC-free linearalkylcarbonate-based electrolyte is developed, which enables the high-voltage(≥4.4V) and low-temperature (-30°C) application of Ni-rich cathode (LiNi0.8Mn0.1Co0.1O2, NCM811). The EC-free system, consisting of LiPF6 and LiNO3 in ternary linear alkyl carbonates, possesses low viscosity, weakly solvated structure, and high interfacial stability with both the Ni-rich cathode and the Li metal anode to avoid continuous electrode/electrolyte side reactions and metal dissolution from the cathode. As a result, the Li||NCM811 cell delivers remarkable capacity retention of 93± 0.5% at the voltage of 4.4V and 88± 0.6% at 4.5V over 100 cycles. This study provides very encouraging perspective to develop EC-free carbonate-based electrolyte for high-voltage and low-temperature application in high-energy-density rechargeable lithium batteries.

Probing the effect of solvents on the electrochemical performance of graphene incorporated nickel-based metal organic frameworks

• The electrochemical performance of Ni-MOFs synthesized in different solvent systems were studied. • Binary solvent system with high polarity and viscosity was favorable for the formation of small-sized nanosheets. • The electrochemical performance was significantly enhanced by incorporating graphene. • The capacitance retention was recorded at 97.70% after 10,000 cycles. Highly porous coordinated metal-organic frameworks (MOFs) have attracted enormous interest by virtue of their promising electrochemical performance in the application of energy storage systems. In this study, the associated electrochemical performance of nickel-based MOFs ([Ni 3 (OH) 2 (C 8 H 4 O 4 ) 2 (H 2 O) 4 ]·2H 2 O, Ni-MOFs) synthesized in different solvent systems was systematically investigated. It is found that binary solvents with high polarity and viscosity were favorable for the formation of small-sized nanosheets. Meanwhile, graphene was incorporated into Ni-MOFs to further enhance the electrochemical performance of the nanocomposite via a facile one-pot solvothermal approach. By taking advantage of the synergistic effect between highly conductive graphene nanosheets and hierarchical Ni-MOFs, the as-synthesized Ni-MOF/graphene nanocomposites exhibited excellent electrochemical performance with significant reduction of charge transfer resistance. The delivered maximum energy and power density of the nanocomposite were 14.68 Wh kg −1 and 2,852 W kg −1 , respectively. Furthermore, a remarkable capacitance retention of 97.70 % over 10,000 cycles was achieved by the nanocomposite electrode, indicating its potential to be applied in high-performance and long cycle-life energy storage devices.

In situ formation of a lithiophilic surface on 3D current collectors to regulate lithium nucleation and growth for dendrite-free lithium metal anodes

As the most promising anode material for lithium batteries, lithium metal faces rigorous challenges such as uncontrollable Li dendrite growth and safety risks, which hinder its practical applications. Herein, a uniform indium layer-decorated Ni foam is constructed as a three-dimensional current collector by electroplating to understand the effects of different substrates on the Li deposition morphology and electrochemical performance and to explore the mechanism for Li dendrite growth. The results indicate that an In3Li13 alloy layer is formed by an alloying reaction, which provides abundant nucleation sites for uniform Li deposition. Both simulations and experiments demonstrate that Li ions tend to deposit on the In3Li13 substrate rather than the Li nucleus, while they prefer to plate onto Li particles rather than onto the Ni substrate. Benefiting from the strong interaction, the In3Li13 substrate shows dispersed Li deposition behavior with a grain-like shape, which is different from the severe dendrite formation of bare Ni substrate. As a result, the In3Li13@NF electrode delivers an enhanced Coulombic efficiency of 97.4% for 300 cycles even under a severe cycling condition of 2 mA cm−2, and the Li-In3Li13@NF anode presents increased cycling stability in symmetric cells. Impressively, the Li-In3Li13@NF//LiFePO4 full cell delivers a remarkable capacity retention of 82.8% for 1000 cycles at 2 C. This work not only sheds light on the growth mechanism for Li dendrites but also provides a new strategy to develop high-energy density lithium metal batteries.

Facile Access to Ni/Co-Based Nanoscale Coordination Polymers for the Boosted Electrochemical Performance of Asymmetric Supercapacitors

Nanoscale coordination polymers (nCPs) have obtained significant attention as cutting-edge materials for energy storage equipment. Nevertheless, monometallic nCPs are often challenging in terms of high capacitance, tunable electrochemical activity, and high conductivity. Herein, an available strategy for boosting the electroconductibility and structure stability of Ni-based nCPs is presented by partially substituting Ni2+ with proper level Co2+ stoichiometry. Co2+ has a beneficial effect on the electrochemical behavior of Ni/Co-nCPs. The bimetallic Ni/Co-nCPs with an appropriate ratio of Ni/Co being 4 has a high Cs of 1160.2 F g–1, which is about 1.47-fold that of Ni-nCPs. When Ni/Co-nCPs are applied as the anode in an asymmetric supercapacitor, the device gives rise to an exceptional energy density of 43.7 W h kg–1 at a power density of 594.9 W kg–1 and a remarkable capacitance retention over 7000 cycles. The strategy established in this work paves a pathway for the rational design and facile preparation of bimetallic Ni/Co-nCPs for energy storage devices with boosting electrochemical properties.

A three-dimensional directly grown hierarchical graces-like Nickel Manganese Selenide for high-performance Li-ion battery and supercapacitor electrodes

In this work, a new, uninvestigated electrode material, Nickel Manganese Selenide (NiMnSe, NMS), is directly prepared on nickel foam, using nickel foam as a substrate and a nickel source. The material demonstrates a well distribution at nickel foam skeleton as extraordinary three-dimensional hierarchical graces-like morphology with a nanosheet structure, promoting a high surface area and excellent electrochemical properties. For the Li-ion battery, the NMS electrode demonstrates a capacity for the first discharge cycle of 1,040 mAh/g and 600 mAh/g for the subsequent discharge cycle at 100 mA/g. For supercapacitor application, the NMS electrode exhibits a specific capacity of 1,950 C/g at 0.5 A/g, with a remarkable coulombic efficiency and capacity retention even at the high current of 10 A/g. A hybrid two-electrode system with an NMS electrode used as a cathode and bismuth selenide (Bi2Se3) as an anode is fabricated to introduce the novel electrode for practical application and reveals specific energy of 65.6 Wh/kg at a specific power of 632.7 W/kg. It retains specific energy of 18.2 Wh/kg at a specific power of 6,560 W/kg, making it a potential electrode for energy storage devices.

Ultra-foldable integrated high-performance in-plane micro-supercapacitors from laser-induced selective metallization

The popularity of flexible and wearable electronic devices has stimulated the development of flexible energy storage devices, in which micro-supercapacitor (MSCs) are the most promising. Herein, we demonstrated a novel strategy for scalable fabrication of copper-nickel-polypyrrole (Cu-Ni-PPy) MSCs devices through laser-induced selective metallization of Cu interdigitated electrode combined with electroplating Ni and electrochemical deposition active material of PPy. The prepared Cu-Ni current collector exhibit high electrical conductivity and mechanical flexibility. Moreover, the obtained Cu-Ni-PPy MSCs devices display a large areal capacitance of 126.67 mF/cm2 and a high volume energy density of 31.78 and 5.39 mWh/cm3 at the corresponding power density of 0.15 and 7.5 W/cm3, respectively. Besides, the MSCs exhibit remarkable capacity retention of 94.8% after 10,000 bending cycles and 89.3% after 10,000 cycles. The wireless charging of the MSCs device can be realized by reasonably designing the wireless charging coil (WCO) for electromagnetic conversion. It is believed that this work provides insight into the manufacture of portability and flexibility of miniaturized energy storage devices.

Novel polyimide binder for achieving high-rate capability and long-term cycling stability of LiNi0.8Co0.1Mn0.1O2 cathode via constructing polar and micro-branched crosslinking network structure

LiNi0.8Co0.1Mn0.1O2 (NCM811) material, as the promising cathode candidate for next-generation high-energy lithium-ion batteries, has gained considerable attention for extremely high theoretical capacity and low cost. Nevertheless, the intrinsic drawbacks of NCM811 such as unstable structure and inevitable interface side reaction result in severe capacity decay and thermal runaway. Herein, a novel polyimide (denoted as PI-OmDT) constructed with the highly polar and micro-branched crosslinking network is reported as a binder material for NCM811 cathode. The micro-branched crosslinking network is achieved by using 1,3,5-Tris(4-aminophenoxy) benzene (TAPOB) as a crosslinker via condensation reaction, which endows excellent mechanical properties and large free volume. Meanwhile, the massive polar carboxyl (−COOH) groups provide strong adhesion sites to active NCM811 particles. These functions of PI-OmDT binder collaboratively benefit to forming the mechanically robust and homogeneous coating layer with rapid Li+ diffusion on the surface of NCM811, significantly stabilizing the cathode structure, suppressing the detrimental interface side reaction and guaranteeing the shorter ion-diffusion and electron-transfer paths, consequently enhancing electrochemical performance. As compared to the NCM811 with PVDF binder, the NCM811 using PI-OmDT binder delivers a superior high-rate capacity (121.07 vs. 145.38 mAh g−1) at 5 C rate and maintains a higher capacity retention (80.38% vs. 91.6%) after 100 cycles at 2.5–4.3 V. Particularly, at the high-voltage conditions up to 4.5 and 4.7 V, the NCM811 with PI-OmDT binder still maintains the remarkable capacity retention of 88.86% and 72.5% after 100 cycles, respectively, paving the way for addressing the high-voltage operating stability of the NCM811 cathode. Moreover, the full-charged NCM811 cathode with PI-OmDT binder exhibits a significantly enhanced thermal stability, improving the safety performance of batteries. This work opens a new avenue for developing high-energy NCM811 based lithium-ion batteries with long cycle-life and superior safety performance using a novel and effective binder.

Advanced In Situ Induced Dual‐Mechanism Heterointerface Towards Ultrastable Aqueous Rocking‐Chair Zinc‐Ion Batteries

AbstractThe practical application of infancy‐stage rocking‐chair Zn‐ion batteries is predominately retarded by the strong electrostatic interaction between traditional anode materials with bivalent Zn2+, resulting in irreversible serious structural damage, unsatisfactory cycling stabilities, and poor rate performances. Herein, an advanced dual electric field in situ induced intercalation/conversion dual‐mechanism Na1.6TiS2/CuSe2 heterointerface anode towards ultrastable aqueous rocking‐chair zinc‐ion batteries is successfully constructed. The rational constructions of huge heterointerfaces between different phases generate built‐in electric fields, reducing the energy barrier for ion migration, facilitating electron/ion diffusion, decreasing charge transfer resistances, and establishing an excellent conducting network. The enhanced interactions of different atoms at the phase interface alleviate the tensile strain and stabilize the lattice, achieving superior Zn2+ diffusion kinetics. The dual‐mechanism Na1.6TiS2/CuSe2 heterostructures can reach a discharge capacity of 142 mAh g−1 at 0.2 A g−1. It still reaches a discharge capacity of 133 mAh g−1 when the current density recovers to 0.2 A g−1 after a high current evaluation of 10 A g−1 with remarkable capacity retention (83.8% at 5A g−1 after 12 000 cycles). This breakthrough opens a new avenue for the targeted design of rocking‐chair zinc‐ion batteries and provides insights into the evolution of heterointerfaces.

A multifunctional subassembly of carbon nanotube paper for stable lithium metal anodes

Uncontrolled lithium growth and the consequent interfacial reaction are obstacles to the practical application of lithium metal anode. Here, a multifunctional subassembly of carbon nanotube paper grafted with a thin layer of LiNO3 (LNO@CP) is proposed. According to the results of experiments and theory calculation, the nucleation sites are enriched and the nuclei are tailored into spherical shape on LNO@CP. Consequently, the Li plating gradually fills the void of LNO@CP and then grows outward uniformly, resulting in an increased Li reversibility and a stable solid electrolyte interphase layer. The LNO@CP covering the Li backup source works as a protective layer to defense the electrolyte corrosion effectively. The lithium metal battery with this multifunctional subassembly delivers a remarkable capacity retention of 81.2% after 500 cycles. This work emphasizes that the a protective layer such as LNO@CP is crucial to the high performance lithium metal battery.

High mass loading NiCoAl layered double hydroxides with interlayer spacing and interface regulation for high-capacity and long-life supercapacitors

To obtain high energy density supercapacitors (SCs) to meet the larger demand for electric vehicles and portable electronic products, increasing the mass loading of electrode materials without sacrificing electron and ion conductivity is an ideal avenue. Herein, stable α-phase NiCoAl hydroxides with an expanded interlayer spacing and superior electronic conductivity are efficiently synthesized via the coprecipitation method. Furthermore, the interface is ingeniously regulated by adjusting the proper concentration of the electrolyte to modulate the charge storage form of the electrode to resolve the structure collapse and block ion penetration/diffusion. As expected, the obtained NiCoAl-10 supercapacitor electrode under an ultrahigh mass loading (20.24 mg cm−2) has an ultrahigh area-specific capacitance of 23.85 F cm−2 at 10 mA cm−2, an excellent rate capability of 19.27 F cm−2, even at 40 mA cm−2, and an outstanding long-term cycling stability (87.5% capacity retention after 10,000 cycles). Ultimately, an asymmetric supercapacitor (ASC) device of NiCoAl-10//active carbon (AC) also exhibits a high energy density of 3.29 mWh cm−2 at 18.00 mW cm−2 and remarkable capacity retention. This work further interprets the energy storage mechanism of NiCoAl hydroxides under high mass-loading, and opens a new avenue for meeting the commercial application of high energy density SCs.

The development of NiCo2O4/PVP/PANI heterogeneous nanocomposites as an advanced battery-type electrode material for high-performing supercapacitor application

Recently, various electroactive materials composed of binary transition metal oxides (TMOs), and conducting polymers have been extensively studied, with the materials demonstrating great potential in high-performing battery-type electrodes. Furthermore, the development of heterogeneous nanocomposites is a versatile approach because of their well-defined surface morphology and the significant synergistic effect of the various species. In this study, NiCo2O4 (NCO) combined with polyvinyl pyrrolidone (PVP) and polyaniline (PANI) hybrid nanocomposites of NCO/PVP/PANI are newly developed using a facile hydrothermal method. The NCO in combination with PVP and PANI species provides the interconnected hierarchical characteristics by offering large electroactive sites that facilitate the charge transfer. The NCO/PVP/PANI1.5 nanocomposites had a high areal capacity of 698.44 µAh cm−2 at a current density of 4 mA cm–2 and a remarkable capacitance retention of 86 % over 4,000 galvanostatic charge/discharge (GCD) cycles owing to its excellent synergistic effect of the rich faradaic redox reaction kinetics of metallic species, and highly conductive materials. Moreover, the proposed NCO/PVP/PANI1.5 battery-type positive electrode was successfully assembled with an activated carbon negative electrode, resulting a hybrid device with a high energy density of 27.60 Wh kg−1 at a power density of 874.9 W kg−1 and excellent cycling stability. This research holds the significant promise for advanced heterogeneous materials in energy storage systems by describing the newly developed nanocomposites.

Rational design of selenium inserted 1T/2H mixed-phase molybdenum disulfide for energy storage and pollutant degradation applications

MoS2 based materials are recognized as the promising candidate for multifunctional applications due to its unique physicochemical properties. But presence of lower number of active sites, poor electrical conductivity, and less stability of 2H and 1T MoS2 inherits its practical applications. Herein, we synthesized the Se inserted mixed-phase 2H/1T MoS2 nanosheets with abundant defects sites to achieve improved overall electrochemical activity. Moreover, the chalcogen insertion induces the recombination of photogenerated excitons and enhances the life of carriers. The bifunctional energy storage and photocatalytic pollutant degradation studies of the prepare materials are carried out. Fabricated symmetric solid-state supercapacitor showed an exceptional capacitance of 178 mF cm−2 with an excellent energy density of 8 μWh cm−2 and power density of 137 mW cm−2, with remarkable capacitance retention of 86.34% after successive 8000 charge–discharge cycles. The photocatalytic dye degradation experiments demonstrate that the prepared Se incorporated 1T/2H MoS2 is a promising candidate for dye degradation applications. Further, the DFT studies confirmed that the Se inserted MoS2 is a promising electrode material for supercapacitor applications with higher CQ due to a larger density of states near Fermi level as compared to pristine MoS2.

Balanced coordination enables low-defect Prussian blue for superfast and ultrastable sodium energy storage

As a promising cathode material of sodium-ion batteries, the crystallinity of Prussian blue and its analogues (PB/PBA) is extremely pivotal for the electrochemical reaction kinetics and longevity. However, the controllable modulation of the PB/PBA crystallinity still remains an intractable challenge. Herein, we propose a balanced coordination principle to prepare low-defect Prussian blue (LD-PB) materials for outstanding sodium energy storage. Sodium carboxymethylcellulose is demonstrated as a moderate chelating agent to regulate the precipitation of LD-PB with negligible trace of vacancies and crystal water molecules. The high-crystalline open framework permits superfast and highly reversible sodium insertion/extraction. Impressively, an unprecedented specific capacity of 101 mAh g−1 is achieved at an ultrahigh rate of 100 C in combination with remarkable capacity retention of 97.4% over a 3000-cycling test. The present study will shed a fundamental insight into the balanced coordination strategy for advancing the PB/PBA cathode materials toward superfast and durable alkali-metal energy storage.

Optimization of Sr-doping boosting the structural stability for single crystalline LiNi0.8Co0.1Mn0.1O2 cathode to enhance its electrochemical performance at elevated voltage and temperature

Single crystalline (SC) Ni-rich cathodes have been considered the potential cathodes for the next generation lithium-ion batteries. Unfortunately, some inevitable defects, such as severe irreversible phase transition, microcracks formation and transition metal dissolution at high voltage, hinder its commercial applications. Herein, a high stable modified SC-LiNi0.8Co0.1Mn0.1O2 cathode is prepared by using Sr doping strategy, which is helpful to tackle the above challenges simultaneously. The introduction of Sr atoms can occupy the transition metal sites of the material, resulting in the increase of Li/Ni exchange energy and the improvement of oxygen layer stability. Meanwhile, Sr doping can promote the growth of primary particles and reduce the agglomeration of SC particles. The optimized doped sample of 0.5Sr-NCM exhibits pronounced improvements in pouch-type full cell with a remarkable capacity retention of 86.6% after 1200 cycles at 1C between 2.8 and 4.35 V (45 °C), while the pristine sample only shows a capacity retention of 80.8% after 798 cycles. The mechanism of enhanced electrochemical properties for the doped sample is revealed by the characterization analyses and density functional theory calculation. This work provides a facile strategy to regulate the bulk structure of SC Ni-rich materials, which may promote the development of high-energy-density lithium-ion batteries.

Sustainable Free‐Standing Electrode from Biomass Waste for Sodium‐Ion Batteries

AbstractBattery sustainability is often neglected in favor of higher performance and economic efficiency in battery technology. The standard electrode containing the use of binder and toxic solvent has a detrimental impact on the environment. For the first time, a sustainable and free‐standing carbonized silk battery anode is prepared from woven silk biomass waste. The unique mechanical structural properties and surface functionality make this material not only avoid the use of binder and organic solvent, but with the possibility of achieving high energy density batteries. An outstanding initial Coulombic efficiency of 75.6 % and a remarkable capacity retention of 100 % after 100 cycles are achieved for the electrode carbonized at 1300 °C (CS_1300 °C) when using a non‐volatile and non‐flammable superconcentrated ionic liquid electrolyte. A uniformly NaF‐distributed solid electrolyte interphase (SEI) layer is produced on the CS_1300 °C surface to facilitate Na+ transfer kinetics, and high capacity utilization. Surface functional groups are elucidated by X‐ray photoelectron spectroscopy (XPS), while density functional theory calculations reveal that these groups accelerate fast Na+ ion adsorption on the surface, but hinder Na+ intercalation kinetics due to the strong binding energy from the sodiophilic sites. This scalable and cost‐efficient strategy opens up a new avenue for mass‐production of battery anode materials, and proposes an argument for the role of surface functional groups in SEI formation and electrochemical performance.