High Initial Columbic Efficiency Research Articles

The induced formation and regulation of closed-pore structure for biomass hard carbon as anode in sodium-ion batteries

Biomass hard carbon is regarded as an advanced anode materials for sodium ion batteries (SIBs) since it possesses balanced performance including satisfactory specific capacity, suitable operating voltage window and low cost. Although numerous instances of utilizing biomass-derived hard carbon in SIBs have been observed, the unregulated pore structure of these hard carbon materials significantly constrains the electrochemical performance of SIBs, leading to diminished initial Columbic efficiency (ICE) and plateau capacity. Herein, taking a biomass hard carbon derived from waste camellia seed shells (CSSHCs) as a template, we display a correlation between synthesis conditions and pore structure of CSSHCs. CSSHCs are synthesized via a facile route including pre‑carbonization, purifying, mechanical ball-milling and high-temperature carbonization, and it is found that adjusting the secondary calcination temperature can induce the formation of closed pore structure, which is of great benefit to increase the ICE and the plateau-capacity. Besides, it is also proved that the obtained CSSHCs anodes obey a sodium storage mechanism that can be classified as “adsorption-intercalation-pore filling”, which endows SIBs with a competitive electrochemical performance. Specifically, the obtained biomass hard carbons at 1300 °C exhibits the best electrochemical performance among these anodes with the reversible capacity of as high as 270.0 mAh g−1 and a high ICE of 80.1 %, together with an excellent cycle stability (91.0 % capacity retention after 200 cycles at 0.1C, 1C = 300 mA g−1). Therefore, this study provides a significant exploration and raw material support for the further utilization of the waste biomass and sustainable development of the anode materials for the large-scale application of SIBs.

(Invited) Novel Q Carbon Anodes for Sodium-Ion Batteries

The main goal of this research is to develop low-cost anodes for sodium-ion batteries. Lack of standard carbon intercalation/insertion anode for sodium-ion batteries has greatly hindered its application. Two types of Q carbons have been studied as a potential anode material for sodium-ion batteries. Q1 carbon exhibits a high initial columbic efficiency of 81% but has a low-capacity retention of less than 60%. Whereas Q2 carbon has a low initial columbic efficiency of 58% but has a high-capacity retention of 81%. Q2 exhibited a stable capacity of 168 mAh/g at a cycling rate of C/3 which is comparable to other high performing hard carbon anodes. This work will discuss in detail about the synthesis procedure, microstructural and electrochemical performance of the Q carbons. This study reports the successful pathway of using Q carbon as a promising anode for sodium ion batteries.ACKNOWLEDGEMENTSThis research was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.

Effect of Electrolytes on Performance of Tire Derived Carbon for Sodium-Ion Batteries

Sodium-ion batteries (SIBs) have recently become prominent in the battery ecosystem due to their low cost and use of earth abundant materials such as Sodium, Manganese, Aluminum, Iron, and Prussian blue (iron cyanide). [1] Graphite is the standard anode used for LIBs but cannot be used in SIBs due to interlayer distance being too small to accommodate Na+ ion. Hard carbons are suitable candidates for SIB due to their low cost, low working potential, high capacity, and ability to be synthesized at lower pyrolysis temperatures. In our past work we have reported a low-cost, scalable waste tire-derived carbon as an anode for SIBs [2]. In this work we test the tire derived carbon with 6 different electrolytes and understand the impact each has on the performance. The best electrolyte was found to be sodium hexafluorophosphate in ethylene carbonate (EC)–ethyl methyl carbonate (EMC) (NaPF6-EC/EMC) which showed a capacity of 108 mAh/g after 200 cycles at charge/discharge rate of C/3. The initial columbic efficiency (ICE) was found to be 52% and to mitigate this problem we tried a scalable contact pre-sodiation method. The pre-sodiation method showed high initial columbic efficiency drastically improving capacity retention of the battery.

Metal Chloride‐Induced Hydrogen Transfer Enables Efficient Conversion of Aromatic Hydrocarbons for Sodium Storage

AbstractThe cost‐effective synthesis of high‐performance hard carbons (HCs) is a key step of sodium‐ion batteries toward practical applications. Considering the rich resource of low‐value aromatic hydrocarbons (e.g., pitch), there is tremendous interesting in its conversion into value‐added HCs. Unfortunately, it still lacks an efficient way for the synthesis, in addition to the time‐consuming oxygen contamination of the carbon framework. Herein, a universal strategy is reported that enables the efficient synthesis of HCs from pitch by modulating hydrogen transfer using metal chlorides. CuCl2 is selected as the model modulator and the effect of different metal chlorides (FeCl3, AlCl3, ZnCl2, and MgCl2) are further explored. Based on material characterizations and density functional theory calculation employing 1‐methylnaphthalene as the model molecule, it shows that the hydrogen capture and chlorination reactions mediated by CuCl2 and FeCl3 are thermodynamically favored, which promote the crosslinking of pitch to form HCs. After optimization, the derived HC exhibits superior performance of reversible capacity of 304.8 mAh g−1 and a high initial Columbic efficiency of 88.4%. These discoveries provide new insights into the synthesis of HCs from aromatic hydrocarbons, facilitating their utilization in electrochemical energy storage.

In-situ confining selenium within bubble - like carbon nanoshells for ultra-stable Li-Se batteries.

Lithium-selenium (Li-Se) batteries are promising energy storage devices. However, the long-term durability and high-rate performance of the Se cathode have been limited by significant volume expansion and the troublesome shuttle effect of polyselenides during repeated charging/discharging processes. To revolutionize these issues, we applied a top-down strategy through the in-situ trapping of amorphous Se within bubble-like carbon (BLC) frameworks, which can radically minimize the presence of surface-absorbed Se while enhancing Se loading capacity. This ingenious technique successfully encapsulates all Se species within carbon nanoshells, creating a distinct half-filled core-shell structure known as Se@void@BLC. This in-situ trapping approach ensures the efficient management of Se volume changes during repeated discharge and charge cycles. Moreover, an extraordinary Se loading capacity of up to 65.6 wt% is reached. Using the Se@void@BLC as cathode for Li-Se battery, we achieve a high initial Columbic efficiency of 84.2 %, a high reversible capacity of 585 mAh g-1 , and an ultralow capacity decay of only 0.0037 % per cycle during 4000 cycles at 10 A g-1 .

Temperature-dependence of calcination processes of Ni-rich layered oxides

High-Ni layered lithium transition metal oxides, LiNi1−x−yMnxCoyO2 (1-x-y≥0.7), show great promise for application in next-generation lithium ion batteries because of their high energy density, low cost, and superior electrochemical properties. However, preparation of stoichiometric LiNi1−x−yMnxCoyO2 oxides with highly ordered layered structure is challenging, largely due to the Li/O loss during high-temperature calcinations. Thus, understanding the reaction mechanism is crucial for calcination design. Herein, X−ray diffraction in combination with nuclear magnetic resonance, are conducted to track the structural evolution in preparing LiNi1−x−yMnxCoyO2 below 500 °C. Our results reveal that a lithiated intermediate, Ni0.7Mn0.15Co0.15(OHy)2Lix, between the precursory transition metal hydroxide and the destination layered LiNi1−x−yMnxCoyO2 phase is generated, bypassing the formation of transition metal oxide phases. The unique reaction enables the calcination optimization at low temperature. Accordingly, high-ordered LiNi0.7Mn0.15Co0.15O2 is achieved via a developed two-step calcination at 500 °C, and it exhibits an excellent electrochemical performance, especially the high initial columbic efficiency.

Architecture and performance of Si/C microspheres assembled by nano-Si via electro-spray technology as stability-enhanced anodes for lithium-ion batteries

Si-based anodes have revealed the potential as the next generation of lithium ion battery anode material, whereas the poor conductivity and huge volume changes during (de)lithiation process of silicon still limit their practical application. Herein, the Si/nitrogen doped carbon layer/carbon framework microspheres (SCM) are designed by nano-Si via electro-spray technology as anodes for lithium ion batteries. It has been found that the SCM consists of individual carbon-coated nano-Si primary particles linked by PAN framework, in which the carbon buffer layer can further absorb the stress of volume changes during charge/discharge process, and the carbon framework carbon framework not only provides fast diffusion path of electron, but also effectively reduces the consumption of electrolyte. Therefore, the initial columbic efficiency (ICE) of SCM anode can reach as high as 72%, and the SCM anode also shows a high specific capacity of 1192 mAh g−1 at 0.2 A g−1 and keeps a reversible capacity of 746 mAh g−1 after 200 cycles, demonstrating the as-designed SCM possesses an high ICE and a good electrochemical performance. This strategy provides a significant inspiration for fabricating high-performance Si/C anode materials of lithium-ion battery.

Mo/Moo2/C Formed by Reducing Mo-Mofs One Step with High Initial Columbic Efficiency and Excellent Lithium-Ion Storage Performance

Mo/Moo2/C Formed by Reducing Mo-Mofs One Step with High Initial Columbic Efficiency and Excellent Lithium-Ion Storage Performance

An ultra-stable anode material for high/low-temperature workable super-fast charging sodium-ion batteries

• Develop a strategy of 3D hierarchical FeSe 2 /rGO hybrids for anodes in SIBs. • The FeSe 2 /rGO anode exhibits extraordinary rate capacity and stable cycling life. • The FeSe 2 /rGO anode has excellent feasibility from –40℃ to 60℃. • FeSe 2 /rGO//Na 3 V 2 (PO 4 ) 3 /C full-cell delivers a high and stable energy density. An ideal rechargeable battery will possess the merits of high specific capacity, long cycling stability, short charging time, high initial coulombic efficiency, wide working temperature range, and low cost. Sodium-ion batteries (SIBs) are expected as the next generation of energy storage devices, but achieving the above features is still a major challenge. Herein, we have developed the 3D hierarchical FeSe 2 /rGO hybrids by a rational hydrothermal method for anodes in SIBs. The FeSe 2 /rGO hybrid SIBs exhibit high rate capacity (205.0 mAh g −1 at 75 A g −1 vs 458.6 mAh g −1 at 0.5 A g −1 ), ultra-stable cycling life (417.7 mAh g −1 after 6000 cycles at 5 A g −1 with a rather low decay rate of only 0.0006% per cycle), extremely high initial columbic efficiency (~98.6%), and excellent feasibility in a wide temperature range (–40℃ to 60℃). Besides, the FeSe 2 /rGO// Na 3 V 2 (PO 4 ) 3 /C full cell delivers an energy density about 145 Wh kg −1 after 200 cycles at 0.15 A g −1 (286 W kg −1 ). The excellent electrochemical performances of FeSe 2 /rGO hybrid SIBs as an ideal rechargeable battery for the next-generation energy storage system.

Pseudocapacitance enhanced by N-defects in Na3MnTi(PO4)3/N-doped carbon composite for symmetric full sodium-ion batteries

The concept of symmetric full battery attracts increasing attention in recent years. The symmetric battery consists of two identical ‘bifunctional’ electrode materials, which can be used as both the cathode and anode. The NASICON-structured Na3MnTi(PO4)3 is capable to be used as a bifunctional electrode for symmetric sodium-ion full battery because of its multiredox reaction with a suitable voltage gap. However, it suffers from limited capacity and poor rate performance. In this study, Na3MnTi(PO4)3 particulates embedding in the N-doped carbon matrix material (NMTP/C–N) are constructed. Both the experiments and density functional theory (DFT) calculations show that the N-defects in the carbon matrix have stronger adsorption energy toward Na+, and the N-vacancy defects have lower diffusion barriers for sodium-ion diffusion, thus enabling higher pseudocapacitance of the NMTP/C–N. By virtue of the enhanced reaction kinetics and pseudocapacitance, the NMTP/C–N demonstrates improved specific capacity and high-rate capability in both high- and low-voltage ranges (2.5–4.2 V vs. Na/Na+; 1.5–2.5 V vs. Na/Na+), where it is operated as the cathode and anode basing on the redox of Mn2+/Mn4+ and Ti4+/Ti3+, respectively. When constructed to a symmetric full battery, it exhibits a moderate reversible capacity of 91.8 mAh/g with a high initial Columbic efficiency of 85.2%, and maintains 70.8% of discharge capacity after 400 cycles at 1C. This work deepens our understanding of materials design for enhanced pseudocapacitance and electrochemical performances.

CoSe@N-Doped Carbon Nanotubes as a Potassium-Ion Battery Anode with High Initial Coulombic Efficiency and Superior Capacity Retention.

Potassium-ion batteries (KIBs) have gained significant interest in recent years from the battery research community because potassium is an earth-abundant and redox-active metal, thus having the potential to replace lithium-ion batteries for sustainable energy storage. However, the current development of KIBs is critically challenged by the lack of competitive electrode materials that can reversibly store large amounts of K+ and electrolyte systems that are compatible with the electrode materials. Here, we report that cobalt monochalcogenide (CoSe) nanoparticles confined in N-doped carbon nanotubes (CoSe@NCNTs) can be used as a K+-storing electrode. The CoSe@NCNT composite exhibits a high initial Columbic efficiency (95%), decent capacity (435 mAh g-1 at 0.1 A g-1), and stability (282 mAh g-1 2.0 A g-1 after 500 cycles) in a 1 M KPF6-DME electrolyte with K as the anode over the voltage range from 0.01 to 3.0 V. A full KIB cell consisting of this anode and a Prussian blue cathode also shows excellent electrochemical performance (228 mAh g-1 at 0.5 A g-1 after 200 cycles). We show that the NCNT shell is effective not only in providing high electronic conductivity for fast charge transfer but also in accommodating the volume changes during cycling. We also provide experimental and theoretical evidence that KPF6 in the electrolyte plays a catalytic role in promoting the formation of a polymer-like film on the CoSe surface during the initial activation process, and this amorphous film is of critical importance in preventing the dissolution of polyselenide intermediates into the electrolyte, stabilizing the Co0/K2Se interface, and realizing the reversibility of Co0/K2Se conversion.

{010} oriented Li1.2Mn0.54Co0.13Ni0.13O2@C nanoplate with high initial columbic efficiency

Lithium rich Mn-based oxide with high capacity and low cost has been viewed as a promising cathode for lithium ion batteries with high energy density. However, there still exists the drawback of the low initial columbic efficiency that caused by the irreversible electrochemical activation of Li2MnO3. Here, {010}-oriented Li1.2Mn0.54Co0.13Ni0.13O2@C nanoplate is prepared by using active carbon to absorb the ethylene glycol solution containing Li+, Co2+, Mn2+ and Ni2+ after the calcination at 850 °C. Ethylene glycol contributes to the formation of the exposed {010} planes, the nanoplate morphology and oxygen vacancies (OVs). The as-prepared material presents a reversible capacity of 276 mA h g−1 and high initial columbic efficiency of 92% at 25 mA g−1, superior rate capability and excellent cycling stability. The high initial columbic efficiency is mainly due to OVs with the function to decrease the irreversible charge capacity related with oxygen release over 4.5 V. And the rate capability is improved by the exposed {010} planes for the enhanced Li+ diffusion and the coating carbon for the excellent electron conductivity. Our work provides a facile method for exposing {010} active planes in lithium rich Mn-based oxide with high initial columbic efficiency.

Cation-deficient TiO2(B) nanowires with protons charge compensation for regulating reversible magnesium storage

Abstract Magnesium battery is a recently emerging energy storage system that has attracted considerable attention. However, its development is limited by the lack of proper electrode materials for reversible Mg2+ intercalation/de-intercalation with satisfied capacity. Here, we firstly report easy synthesis of Ti-deficient bronze titanium dioxide nanowires by topology transformation of H-titanate precursor. It's found OH− anions substitution of O2− supports the formation of Ti vacancies in TiO2(B) with a high concentration, denoted as (Ti0.91O1.64(OH)0.36), and can be utilized as a robust host for Mg-ion storage. Both the theoretical and experimental study revealed that Ti-deficient TiO2(B) exhibits much improved electronic properties with unpaired electrons. Density functional theory (DFT) calculations also reveal Ti vacancies provide more feasible binding sites for Mg-ion. More importantly, it's surprisingly found the presence of protons enables a suitable binding energy for Mg-ion intercalation and extraction. As a result, such material displays discharge and charge capacities of 217.3 and 165.3 mA h g−1 at 0.02 A g−1, representing the highest value among the reported Ti-based electrode materials as well as a high initial Columbic efficiency up to 76.1%. This study gives a new and in-depth view on how cation-deficient structure regulates and promotes the reversible energy storage.

Optimizing the Crystallite Structure of Lignin‐Based Nanospheres by Resinification for High‐Performance Sodium‐Ion Battery Anodes

Sodium‐ion batteries are expected to be an alternative to lithium‐ion batteries because of the inexpensive raw materials. However, the anode materials still face problems of low capacity and initial coulomb efficiency, even for hard carbons that are expected to have commercial applications. Herein, a resin nanosphere derived from lignin through double solvent evaporation and resinification is reported. Benefiting from the phenol–formaldehyde condensation to form linear polymers, the samples possess a large microcrystalline size, moderate interlayer distance, and defect sites in the turbostratic structure, which enhance the sodium‐storage capacity. The carbonized lignin‐based resin spheres (CLRSs) exhibit promising electrochemical performance with a comparable reversible capacity of 347 mAh g−1 and high initial columbic efficiency (ICE) of 74%. Furthermore, the sodium‐storage mechanism for the obtained samples is also investigated by analyzing the relationship between the structure optimization and electrochemical performance.

Facile synthesis of MoO2/Mo-GO with high initial columbic efficiency and enhanced lithiation ability

Pure MoO2 and MoO2/Mo are tuned via temperature control in a facile high temperature reduction procedure. Graphene oxide (GO) is then composited into them through physical mixing followed by freeze-drying. When assembled as anodes for Li-ion batteries, samples containing Mo, including MoO2/Mo and MoO2/Mo-GO, possess not only high initial columbic efficiency (ICE) but also high capacity, stability and rate performance. The MoO2/Mo hybrid exhibits a rather high ICE of 97%. The ICE of the MoO2/Mo-GO is still high as 85% with a largely enhanced capacity of 400 mA h g−1, which is gradually increased to 550 mA h g−1 after 150 cycles.

A facile and versatile strategy towards high-performance Si anodes for Li-ion capacitors: Concomitant conductive network construction and dual-interfacial engineering

In this work, we demonstrate an efficiency and versatile strategy for the synthesis of Si-based anodes using low-cost biomass and commercially available Si nanoparticles as precursors via conventional slurry coating and low-temperature pyrolysis. Due to the tailored and rational design, gelatin-derived carbon with numerous heteroatoms not only acts as a “conductive skeleton” to enhance the electron/ion transfer but also simultaneously accommodate the Si expansion and immobilize the Si on the current collector via “dual-interfacial bonding”. Without additional binder and conductive agents, the obtained Si-based anode exhibits high initial columbic efficiency (85.3%), high gravimetric capacity (3160 mAh g−1 at 0.2 A g−1), large areal capacity (2.81 mAh cm−2 at 0.18 mA cm−2, approaching the commercial LIB requirement), good rate capability (1613 mAh g−1 at 5 A g−1) and cycling performance. Consequently, an assembled Li-ion capacitor utilizing the Si-based anode exhibits high energy density (213 Wh kg−1), high power density (22.3 kW kg−1), low discharge rate and long lifetime. The scalable synthetic method combined with high performance making this Si-based anode promising for practical applications.

Hierarchically porous cobalt-carbon nanosphere-in-microsphere composites with tunable properties for catalytic pollutant degradation and electrochemical energy storage

Unreliable energy supply and environmental pollution are two major concerns of the human society in this century. Herein, we report a rational approach on preparation of hierarchically-structured cobalt-carbon composites with tunable properties for a number of applications. A facile hydrothermal treatment of cobalt nitrate and sucrose results in the formation of a metallic cobalt-amorphous carbon composite with cobalt nanospheres anchored homogenously on an amorphous carbon substrate. Tuning the calcination conditions in air will generate either a metallic cobalt-cobalt oxide core-shell structure with magnetism or a fully oxidized Co3O4 composite. The different materials are demonstrated as anodes for lithium-ion batteries (LIBs) and catalysts for advanced oxidation-based wastewater remediation. A fully oxidized composite (FC@CS, fully oxidized Co loaded on carbon spheres) as a LIB anode exhibits superior electrochemical performance, possessing a high reversible capacity, high initial columbic efficiency, outstanding cycling performance and excellent rate capability. The anode performance is superior to most reported Co3O4-based electrodes. Meanwhile, the partially oxidized composite (PC@CS, partially oxidized Co loaded on carbon spheres) functions as an efficient and stable catalyst for removal of phenol via peroxymonosulfate (PMS) activation, which is demonstrated via electron paramagnetic resonance (EPR) and quenching experiments for generation of radicals. More importantly, the recycled PC@CS can be further applied as a LIBs anode after full oxidation regeneration, performing comparably to FC@CS. This FC@CS → PC@CS → FC@CS transformation provides an innovative approach for efficient material synthesis, recycling and application.

MOF-derived ZnCo2O4/C wrapped on carbon fiber as anode materials for structural lithium-ion batteries

To meet the requirements for the mechanical and electrochemical performance for carbon fiber-based (CF-based) composites in the structural lithium ion batteries (SLIBs) application, better CF-Based composites are urgently needed. Herein, we report a novel composite metal organic framework (MOF)-derived ZnCo2O4/C@carbon fiber via a facile method and subsequent annealing treatment. In this anode, the nano ZnCo2O4/C coatings wrapped on the surface of CF provide more active sites for electrode reactions and the thin carbon layers give the additional protection. For this material, after 100 cycles, it exhibits excellent cycling stability including high reversible capacity of 463mAh/g at 50mA/g, which increases 201% than that of the CF. Thus, this structural anode material exhibits enhanced capacity, high initial columbic efficiency.

Novel Silicon Doped Tin Oxide–Carbon Microspheres as Anode Material for Lithium Ion Batteries: The Multiple Effects Exerted by Doped Si

Silicon doped tin oxide embedded porous carbon microspheres (Siy Sn1-y Ox @C) are synthesized. It is found that the doped Si not only improves the reversibility of lithiation/delithiation reactions, but also prevents Sn from aggregation. In addition, the doped Si introduces extra defects into the carbon matrix and produces Li+ conductive Li4 SiO4 , which accelerates Li+ diffusion. Together with the conductive, porous carbon matrix that provides void space to accommodate the volume change of Sn during charge/discharge cycling, the novel Siy Sn1-y Ox @C exhibits excellent electrochemical performance. It shows a high initial columbic efficiency of 75.9%. A charge (delithiation) capacity of 880.32 mA h g-1 is retained after 150 cycles, i.e., 91% of the initial capacity. These results indicate that the as-synthesized Siy Sn1-y Ox @C is a promising anode material for lithium ion batteries.

Ultrahigh level nitrogen/sulfur co-doped carbon as high performance anode materials for lithium-ion batteries

Ultrahigh level nitrogen and sulfur co-doped disordered porous carbon (NSDPC) was facilely synthesized and applied as anode materials for lithium-ion batteries (LIBs). Benefiting from high nitrogen (14.0 wt%) and sulfur (21.1 wt%) doping, electrode fabricated from NS1/3 showed a high reversible capacity of 1188 mA h g−1 at 0.1 A g−1 in the first cycle with a high initial columbic efficiency (>75%). In addition, prolonged life over 500 cycles and excellent rate capability of 463 mA h g−1 at 5 A g−1 have been realized. The preeminent electrochemical performance is attributed to three effects: (1) the high level of sulfur and nitrogen; (2) the synergic effect of dual-doping heteroatoms in cooperation with each other; (3) the large quantity of edge defects and abundant micropores and mesopores that can provide extra Li storage regions. These unique features of NSDPC electrodes suggest that they can serve as a practical substitute for graphite as a high performance anode material in LIBs.