Search

Lithium metal batteries (LMBs) are regarded as one of the most promising next-generation energy storage devices due to their high energy density. However, the conversion of LMBs from laboratory to factory is hindered by the formation of lithium dendrites and volume change during lithium stripping and deposition processes. In this work, a volume-responsive separator with core/shell structure thermoplastic polyurethane (TPU)/polyvinylidene fluoride (PVDF) fibers and SiO

Li metal batteries with high-capacity cathodes emerge as promising candidates for next-generation battery technologies. However, the poor reversibility of the Li deposition/stripping process severely reduces its lifespan, and safety also remains a major issue for the Li metal anodes. Herein, we propose (ethoxy)-penta-fluoro-cyclo-triphosphazene (DFA) as a dual-functional electrolyte additive to solve the engineering problem of balancing the cycle life and thermal stability of Li metal batteries. The NCM811/lithium metal pouch batteries (2900 mA h) are assembled using the commercial high areal capacity cathode (3.5 mA h cm-2). Compared with the NCM811/Li batteries without DFA, the heat generation and heat generation power of lithium metal batteries with DFA are significantly reduced by half during charging. Moreover, the NCM811/Li pouch batteries with DFA show excellent stability in both hot-oven and adiabatic rate calorimeter experiments. Furthermore, a nonlinear phase field simulation is carried out for mechanism investigation, which confirms that the stable solid electrolyte interphase formed by DFA will improve the cycle life of the NCM811/Li pouch. The DFA is verified to be an effective additive to improve the cycle stability and safety simultaneously, providing new opportunities for developing high energy density Li metal batteries.

Nickel-rich LiNixCoyMn1-x-yO2 (nickel-rich NCM, 0.6 ≤ x < 1) cathode materials suffer from multiscale reaction heterogeneity within the electrode during the electrochemical energy storage process. However, owing to the lack of appropriate diagnostic tools, the systematic understanding and observation on the redox reaction heterogeneity at the individual secondary-particle level is still limited. Raman spectroscopy can not only reflect the depth of the redox reaction through probing the vibrational information on the metal-oxygen coordination structure but also sensitively detect the local structure changes of different regions within the secondary particle with suitable spatial resolution. Therefore, Raman spectroscopy is applied here to conveniently conduct the high-resolution and in-depth analysis of the rate-dependent reaction heterogeneity within nickel-rich NCM secondary particles. It is found that, under high-rate conditions, the oxidation/reduction reaction mainly occurs in the surface region of the particles and the cause of this particle-scale reaction heterogeneity is the limitation of the slow solid-phase Li+ diffusion and the transient charging/discharging processes. In addition, this reaction heterogeneity would aggravate the structural instability of the material continuously during the charging/discharging cycles, thus resulting in a slowdown in the kinetics of Li+ de/intercalation and the apparent capacity decay. This work can not only provide fundamental insight into the rational modification of high-power nickel-rich NCM materials but also guide the setting of electrochemical operating conditions for high-power lithium-ion batteries (LIBs).

Lithium (Li) metal is regarded as the holy grail among various anode candidates due to its extremely high specific energy and low electrochemical potential. Nevertheless, uncontrolled dendrite grow...

High nickel content LiNixCoyMn1–x–yO2 (NCM) cathode materials have been attracting increasing attention owing to their significant advantages, but in practical application, because of their poor st...

Cu2S is considered as one of the potential anode paradigms for advanced rechargeable batteries because of its high theoretical capacity (∼335 mAh·g-1), high and flat charge/discharge voltage plateaus (∼1.7 V vs Li+/Li), stable cycling performance, and its elemental abundance. However, many studies have shown that Cu2S exhibits a dramatic capacity fade in carbonate-based electrolytes, which has precluded its commercialization when paired with high voltage cathodes in state-of-the-art lithium ion batteries. Here, we report on a fundamental mechanistic study of the electrochemical processes of Cu2S in both ether- and carbonate-based electrolytes employing operando synchrotron X-ray methods. Based on our findings, we developed a Cu2S/C composite material that suppresses its failure mechanism in carbonate-based electrolytes and further demonstrated its feasibility in lithium ion full cells for the first time. Our experiment provides the basis for the utilization of Cu2S in industrial-scale applications for large-scale electrical energy storage.

In our work, fluoroethylene carbonate (FEC) with higher ionic conductivity and oxidative stability has been used to replace ethylene carbonate along with 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluor...

According to the theoretical calculations and combining the advantages of different solvents, an effective electrolyte capable of effectively improving the high-voltage performance of LiCoO2 (LCO) ...

The high price of fuel cells is mainly attributed to the low catalytic efficiency and short working life of the state-of-the-art commercial catalysts for the oxygen reduction reaction. Hereon, a ni...

The solution combustion synthesis (SCS) has been widely used to prepare varieties of materials, especially oxides. Nevertheless, there are just a few reports applying the SCS to synthesize sulfides, and most of them are prepared under the protection of an inert atmosphere. As the counterpart of metal oxides, the metal sulfides (MSs) also play an important role in energy-related devices. Herein, a novel air atmospheric SCS is proposed to prepare classes of MSs and the corresponding carbon composites. Thanks to the evaporation and flash burning of ethanol, the O2 is consumed, protecting the MSs and the carbon nanotubes (CNTs) from oxidation; thus, the mesoporous CoS, NiS, Cu2S, and the CoS/CNT, NiS/CNT, Cu2S/CNT, can be easily and rapidly obtained by directly combusting in the air atmosphere. Compared to the conventional SCS for synthesizing the MSs, the equipment requirements of this proposed method are low, which is suitable for large-scale preparation. The lithium storage properties of MSs and MSs/CNTs a...

The degradation mechanism of the stored LiNi0.5Co0.2Mn0.3O2 (NCM523) electrode has been systematically investigated by combining physical and electrochemical tests. After stored at 55 °C and 80% re...

In this work, nonstoichiometric Cu2–xSe fabricated by a facile water evaporation process is used as high-performance Al-ion battery cathode materials. Cu2–xSe electrodes show high reversible capacity and excellent cycling stability, even at a high current density of 200 mA g–1, the specific charge capacity in the initial cycle is 241 mA h g–1 and maintains 100 mA h g–1 after 100 cycles with a Coulombic efficiency of 96.1%, showing good capacity retention. The prominent kinetics of Cu2–xSe electrodes is also revealed by the GITT, which is attributed to the ultrahigh electronic conductivity of the Cu2–xSe material. Most importantly, an extensive research is dedicated to investigating the detailed intercalation and de-intercalation of relatively large chloroaluminate anions into the cubic Cu2–xSe, which is conducive to better understand the reaction mechanism of the Al/Cu2–xSe battery.

A blend cathode has been prepared by mixing both LiNi0.5Co0.2Mn0.3O2 (NCM523) of high energy density and high specific capacity and LiFe0.15Mn0.85PO4/C (LFMP/C) of excellent thermal stability via a low-speed ball-milling method. The lithium ion batteries using the blend cathode with LFMP/C of optimum percent exhibit better capacity retention after 100 cycles than those using only single NCM523 or LFMP/C. Both theoretical simulation and experimental rate performances demonstrate that the electrochemical property of blend cathode materials is predictable and economical. In addition, the thermal behaviors of blend cathodes are studied by using differential scanning calorimetry analysis. The thermal stability of blend cathode materials behaves better than that of the bare NCM523 accompanied with an electrolyte. It is found that the outstanding rate and thermal performance of the blend cathode is due to the prominent synergistic effect between NCM523 and LFMP/C, and 10% LFMP/C in the blend cathode materials is the most adaptable as considering both electrochemical and thermal properties simultaneously.

In this study, one-dimensional Cu2–xSe nanorods synthesized by a simple water evaporation-induced self-assembly approach are served as the anode material for Na-ion batteries for the first time. Cu2–xSe electrodes express outstanding electrochemical properties. The initial discharge capacity is 149.3 mA h g–1 at a current density of 100 mA g–1, and the discharge capacity can remain at 106.2 mA h g–1 after 400 cycles. Even at a high current density of 2000 mA g–1, the discharge capacity of the Cu2–xSe electrode still remains at 62.8 mA h g–1, showing excellent rate performance. Owing to the excellent electronic conductivity and one-dimensional structure of Cu2–xSe, the Cu2–xSe electrodes manifest fast Na+ ion diffusion rate. Moreover, detailed Na+ insertion/extraction mechanism is further investigated by ex situ measurements and theoretical calculations.

Co3O4 is emerging as a promising anode candidate for lithium ion batteries (LIBs) with high theoretical capacity (890 mAh g–1) but suffers from poor electrochemical cycling stability resulting from the inferior intrinsic electronic conductivity and large volume changes during electrochemical cycling. Here, a new electrophoretic deposition Co3O4/graphene (EPD Co3O4/G) hybrid electrode is developed to improve the electrochemical performance. Through EPD, Co3O4 nanocubes can be homogeneously embedded between graphene sheets to form a sandwich-like structure. Owing to the excellent flexibility of graphene and a large number of voids in this sandwich-like structure, the structural integrity and unobstructed conductive network can be maintained during cycling. Moreover, the electrode kinetics has proved to be a fast surface-controlled lithium storage process. As a result, the Co3O4/G hybrid electrode exhibits high specific capacity and excellent electrochemical cycling performance. The Co3O4/G hybrid electrode ...

The lithium-sulfur battery is considered as a prospective candidate for a high-energy-storage system because of its high theoretical specific capacity and energy. However, the dissolution and shutter of polysulfides lead to low active material utilization and fast capacity fading. Electrospinning technology is employed to directly coat an interlayer composed of polyacrylonitrile (PAN) and nitrogen-doped carbon black (NC) fibers on the cathode. Benefiting from electrospinning technology, the PAN-NC fibers possess good electrolyte infiltration for fast lithium-ion transport and great flexibility for adhering on the cathode. The NC particles provide good affinity for polysufides and great conductivity. Thus, the polysulfides can be trapped on the cathode and reutilized well. As a result, the PAN-NC-coated sulfur cathode (PAN-NC@cathode) exhibits the initial discharge capacity of 1279 mAh g-1 and maintains the reversible capacity of 1030 mAh g-1 with capacity fading of 0.05% per cycle at 200 mA g-1 after 100 cycles. Adopting electrospinning to directly form fibers on the cathode shows a promising application.

The Li3VO4@C microsphere composite was first reported as a novel cathode material for rechargeable aluminum-ion batteries (AIBs), which manifests the initial discharge capacity of 137 mAh g–1 and and remains at 48 mAh g–1 after 100 cycles with almost 100% Coulombic efficiency. The detailed intercalation mechanism of Al into the orthorhombic Li3VO4 is investigated by ex situ X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) of Li3VO4@C electrodes and the nuclear magnetic resonance aluminum spectroscopy (27Al NMR) of ionic liquid electrolytes in different discharge/charge states. First-principle calculations are also carried out to investigate the structural change as Al inserts into the framework of Li3VO4. It is revealed that the Al/Li3VO4@C battery goes through electrochemical dissolution and deposition of metallic aluminum in the anode, as well as the insertion and deinsertion of Al3+ cations in the cathode in the meantime. The rechargeable AIBs fabricated in this work are of low cost a...

Fe3O4 is regarded as an attractive anode material for lithium ion batteries (LIBs) due to its high theoretical capacity, natural abundance, and low cost. However, the poor cyclic performance resulting from the low conductivity and huge volume change during cycling impedes its application. Here we have developed a facile electrophoretic deposition route to fabricate the Fe3O4/CNTs (carbon nanotubes)/rGO (reduced graphene oxide) composite electrode, simultaneously achieving material synthesis and electrode assembling. Even without binders, the adhesion and mechanical firmness of the electrode are strong enough to be used for LIB anode. In this specific structure, Fe3O4 nanoparticles (NPs) interconnected by CNTs are sandwiched by rGO layers to form a robust network with good conductivity. The resulting Fe3O4/CNTs/rGO composite electrode exhibits much improved electrochemical performance (high reversible capacity of 540 mAh g-1 at a very high current density of 10 A g-1, and a remarkable capacity of 1080 mAh g-1 can be maintained after 450 cycles at 1 A g-1) compared with that of commercial Fe3O4 NPs electrode.

The Prussian blue, as a potential adsorbent of polysulfides to suppress the dissolution and shuttle of polysulfides for lithium–sulfur batteries, has been studied in this work. Our results show that Prussian blue improves the electrochemical reaction kinetics during discharge/charge processes. More importantly, the cathode with Prussian blue exhibits better cycling stability and higher discharge capacity retention (722 mAh g–1 at 0.2 A g–1 after 100 cycles) than the one without Prussian blue (151 mAh g–1). These improvements of electrochemical performances are ascribed to the fact that Prussian blue is very effective in suppressing the dissolution of polysulfides into liquid electrolyte by chemical adsorption.

The layer-structured LiNi0.5Co0.2Mn0.3O2 (L523) with high specific capacity and the spinel LiMn2O4 (LMO) with excellent thermostability complement each other in a blended cathode for better heat stability and electrochemical performance. The delithiated LMO starts to react with electrolyte at 160-200 °C to cause structural instability, and the delithiated L523 generates massive heat when its temperature is raised above 275 °C with the electrolyte present, but we found that the blended cathode shows a remarkable improvement in thermal stability since the reaction at 160-200 °C between LMO and the electrolyte disappears, and the total heat generated from the reaction between L523 and the electrolyte is drastically reduced. The reaction between LMO and the electrolyte at 160-200 °C causes structural instability of LMO as a self-accelerating attack from HF. With L523 present, this reaction is eliminated because the H(+) from HF and Li(+) in L523 undergo exchange reaction to prevent further generation of HF. The presence of LMO, however, reduces the total heat generated by L523 reacting with the electrolyte at high temperature. This thermal synergy between LMO and L523 not only improves the thermal safety of the blended cathode but also preserves their structures for better electrochemical performance.

A series of nitrogen-modified Li4Ti5O12 (N-LTO) nanomaterials with hierarchical micro/nanoporous structures are first synthesized via a facile one-step combustion process using thermal decomposition of urea. Successful deposition of a TiN thin layer onto the LTO surface was confirmed by transmission electron microscopy with energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, Raman spectroscopy, and thermogravimetric measurements. The electrochemical performances of the N-LTO nanomaterials are also investigated in this work. Compared with pristine LTO, the N-LTO nanomaterial with 1.1 wt % nitrogen exhibits a higher rate capability and better reversibility. At charge/discharge rates of 1, 2, 8, and 15 C, the discharge capacities of the N-LTO electrode were 159, 150, 128, and 108 mAh g(-1), respectively. After 200 cycles at 1 C, its capacity retention was 98.5% with almost no capacity fading.