High-capacity Lithium-ion Batteries Research Articles

Light-assisted synthesis of copper/cuprous oxide reinforced nanoporous silicon microspheres with boosted anode performance for lithium-ion batteries

Silicon is generally accepted as an outstanding anode material to promote the use of high-capacity lithium-ion batteries (LIBs). Herein, novel Cu/Cu2O reinforced nanoporous silicon microspheres are successfully constructed by a simple photodeposition-galvanic replacement method. The reduction reactions driven by photogenerated electrons and galvanic replacement jointly promote the in-situ deposition of Cu/Cu2O on porous silicon microspheres. Compared with the as-constructed anode materials in the absence of illumination, the composites obtained with the light irradiation display better electrochemical performance. The ratio of Si and Cu in the final products can be effectively adjusted by modulating the concentration of Cu2+ in the reaction solutions. Benefiting from the enhanced structure stability and excellent electronic conductivity, the final optimized product exhibits superior Li-storage performance, delivering a reversible capacity of 1240.1 mAh g−1 after 200 cycles at a high current of 1 A g−1. It is worth mentioning that the as-constructed light-assisted method provides an efficient and universal pathway to tailor and synthesize other superior Si based anode materials.

Communication—Functional Conductive Polymer Binder for Practical Si-Based Electrodes

Multifunctional conductive binders represent an emerging class of polymer materials to address inherent challenges of Si electrodes for high capacity lithium-ion batteries. Advanced binders with oriented functionalities are greatly desired to facilitate the battery chemistry. We here report stable capacity cycling of a practical composite anode comprising industrial available SiOx (>60 wt%), carbon materials and a conductive polymer binder—poly(9,9-dioctylfluorene-co-fluorenonecomethylbenzoic ester) (PFM). This multifunctional polymer functions as both an interface modifier and an electrode binder for high-performing SiOx composite electrodes. The viability of multifunctional conductive polymer binders was further validated in a practical full cell.

A facile synthesis of phosphorus doped Si/SiO2/C with high coulombic efficiency and good stability as an anode material for lithium ion batteries

Silicon (Si) has the drawbacks of large volume expansion and poor electronic conductivity to be overcome as the anode material for lithium ion batteries (LIBs). Herein, phosphorus (P) doped Si coated by dual layers of SiO2 and carbon (denoted as P-doped Si/SiO2/C) has been synthesized by a facile solid-state route. In that, commercial Si powder and polyvinyl butyral was used as raw material and carbon source, respectively. Importantly, the phosphoric acid was introduced as the doping agent, that also helped the formation of pure SiO2 coating layer rather than the mixture of SiO2 and less oxidized SiOx on surface of the Si material. The as-prepared P-doped Si/SiO2/C material exhibits an initial discharge capacity as high as 2860.3 mAh g−1 and an excellent inital coulombic efficiency of 86.7% at a current density of 200 mA g−1. After 150 cycles, charge capacity of 1389.8 mAh g−1 was retained, indicating the good cycle stability of P-doped Si/SiO2/C material, which is over three times higher than that of the Si/C material (449.2 mAh g−1) without phosphoric acid treatment. Additionally, a capacity enhancement of 25.7%, 40.7%, 79.1% 281.7% and 407.7% was achieved as compared to the Si/C material at the current densities of 100, 300, 600 1000 and 2000 mA g−1, respectively. The P-doping and SiO2 coating have played a significant role on the electrochemical performance by effectively improving the intrinsic electronic conductivity and further suppressing the volume expansion (~40%) of Si in charge-discharge tests respectively. It worth mentioning that the synthesis of P-doped Si/SiO2/C can be easily scaled up. Therefore, our work pave the way toward the industrilization of stable Si-based anode material with high capacity for LIBs.

Research progress of the electrochemical impedance technique applied to the high-capacity lithium-ion battery

The world’s energy system is changing dramatically. Li-ion battery, as a powerful and highly effective energy storage technique, is crucial to the new energy revolution for its continuously expanding application in electric vehicles and grids. Over the entire lifetime of these power batteries, it is essential to monitor their state of health not only for the predicted mileage and safety management of the running electric vehicles, but also for an “end-of-life” evaluation for their repurpose. Electrochemical impedance spectroscopy (EIS) has been widely used to diagnose the health state of batteries quickly and nondestructively. In this review, we have outlined the working principles of several electrochemical impedance techniques and further evaluated their application prospects to achieve the goal of nondestructive testing of battery health. EIS can scientifically and reasonably perform real-time monitoring and evaluation of electric vehicle power batteries in the future and play an important role in vehicle safety and battery gradient utilization.

Using glass defect engineering to obtain order–disorder transformation in cathode for high specific capacity lithium ion battery

Vanadium-based glass shows high electronic conductivity without grain boundaries. It easily undergoes structural microcrack defects during fabrication using the melt-quenching method resulting in voids that affect its properties. This paper demonstrates that the cathode material obtained by nanocrystals precipitated by long-cycle electric fields are identical with those obtained by the heat treatment method. V2O5-Li3PO4 (VP) glass precipitates nanocrystals of Li3P and Li0.3V2O5 under heat treatment at 340 °C. It showed a prominent specific capacity of 269.4 mAh.g−1 in the first cycle at a current density of 50 mA.g−1, and 227.4 mAh.g−1 after 50 cycles with a retention rate of 86.3%, as the cathode of a lithium ion battery. Thermal field-controlled VP glass allows selective crystallization of nanocrystal of Li3P and Li0.3V2O5, which promote conductivity and charge transfer and significantly enhance the electrode reaction kinetics. Through ex-situ TEM, DSC, XRD and XPS, it was observed that discharge/charge caused disordered transitions in the amorphous VP, leading to the formation of nanocrystals of Li3P and Li0.3V2O5 after 100 cycles. Amorphous glass electrode material as a high-energy unstable state, has same tendency of precipitation of crystals to become stable under different treatment methods with long electric field cycles and thermal field induction.

Dually-functionalized Ni-rich layered oxides for high-capacity lithium-ion batteries

Layered lithium nickel-cobalt-manganese oxides (NCM) have been highlighted as advanced cathode materials for lithium-ion batteries (LIBs); however, their low interfacial stability must be overcome to ensure stable cycling performance of the cell. In this work, we propose a one-step surface modification method that uses a task-specific precursor, N,N,N,N-tetraethylsulfamide (NTESA), to improve interfacial stability of Ni-rich NCM cathode materials. The unstable surface properties of Ni-rich NCM cathode material are improved by embedding an artificial cathode-electrolyte interphase (CEI) layer on the cathode surface by heat treatment of the Ni-rich NCM cathode material with an NTESA precursor at low temperature. Our material analyses indicate that this approach allows the formation of amine- and sulfone-functionalized CEI layers on the surface of Ni-rich NCM cathode material without changing the layered structure of the cathode material. NTESA-functionalized Ni-rich NCM cathode materials exhibit improved cycling retention after 100 cycles: for example, a cell cycled with a 3.0 NTESA-modified NCM811 cathode presents the highest retention ratio of 88.3 %, whereas a cell cycled with a non-functionalized NCM811 cathode suffers from rapid fading of the cycling performance (68.4 %). Our additional SEM, XPS, and EIS analyses indicate that electrolyte decomposition is suppressed during electrochemical cycling, thereby leading to smaller increases in the internal resistances. ICP-MS analyses of the cycled anodes also indicate that the NTESA-based artificial CEI layer inhibits the dissolution of transition metal components from the Ni-rich NCM cathode materials, thereby contributing to an improved overall electrochemical performance of the cell.

Highly Stable Cycling of Silicon-Nanographite Aerogel-Based Anode for Lithium-Ion Batteries.

Silicon anodes are considered as promising electrode materials for next-generation high capacity lithium-ion batteries (LIBs). However, the capacity fading due to the large volume changes (∼300%) of silicon particles during the charge–discharge cycles is still a bottleneck. The volume changes of silicon lead to a fracture of the silicon particles, resulting in recurrent formation of a solid electrolyte interface (SEI) layer, leading to poor capacity retention and short cycle life. Nanometer-scaled silicon particles are the favorable anode material to reduce some of the problems related to the volume changes, but problems related to SEI layer formation still need to be addressed. Herein, we address these issues by developing a composite anode material comprising silicon nanoparticles and nanographite. The method developed is simple, cost-efficient, and based on an aerogel process. The electrodes produced by this aerogel fabrication route formed a stable SEI layer and showed high specific capacity and improved cyclability even at high current rates. The capacity retentions were 92 and 72% of the initial specific capacity at the 171st and the 500th cycle, respectively.

Enhanced Electrochemical Performance Promoted by Tin in Silica Anode Materials for Stable and High-Capacity Lithium-Ion Batteries.

Although the silicon oxide (SiO2) as an anode material shows potential and promise for lithium-ion batteries (LIBs), owing to its high capacity, low cost, abundance, and safety, severe capacity decay and sluggish charge transfer during the discharge–charge process has caused a serious challenge for available applications. Herein, a novel 3D porous silicon oxide@Pourous Carbon@Tin (SiO2@Pc@Sn) composite anode material was firstly designed and synthesized by freeze-drying and thermal-melting self-assembly, in which SiO2 microparticles were encapsulated in the porous carbon as well as Sn nanoballs being uniformly dispersed in the SiO2@Pc-like sesame seeds, effectively constructing a robust and conductive 3D porous Jujube cake-like architecture that is beneficial for fast ion transfer and high structural stability. Such a SiO2@Pc@Sn micro-nano hierarchical structure as a LIBs anode exhibits a large reversible specific capacity ~520 mAh·g−1, initial coulombic efficiency (ICE) ~52%, outstanding rate capability, and excellent cycling stability over 100 cycles. Furthermore, the phase evolution and underlying electrochemical mechanism during the charge–discharge process were further uncovered by cyclic voltammetry (CV) investigation.

Anchored CoCO3 on peeled graphite sheets toward high-capacity lithium-ion battery anode

Anchored CoCO3 on peeled graphite sheets toward high-capacity lithium-ion battery anode

Core–shell structured monodisperse carbon-rich SiO1.31C1.46H0.81 ceramic spheres as anodes for high-capacity lithium-ion batteries

SiOC ceramic material is a promising anode material for lithium-ion batteries. However, due to its intrinsically low electronic conductivity, it often suffers from a much lower specific capacity than the theoretical value, poor rate capability and serious potential hysteresis. In this paper, we report a core–shell structured monodisperse carbon-rich SiO1.31C1.46H0.81 submicron ceramic sphere with a free carbon content of 13.7 wt%, which is synthesized by directly annealing polysiloxane spheres derived from vinyltrimethoxysilane without adding external carbon resources. The SiO1.31C1.46H0.81 sphere has a unique microstructure, the core of which is organically assembled by large amounts of SiO1.31C1.46H0.81 primary particles of less than 20 nm and coated by a shell of 20–50 nm. As anodes for lithium-ion batteries, it presents much higher reversible capacity, initial Coulomb efficiency (ICE) and rate performance than the SiOC-based ceramic materials reported in the literature to date. At 100 mA g−1, its first reversible capacity and ICE reach ∼1107 mAh g−1 and 78.2%, respectively. At 1600 mA g−1, its stable discharge capacity is still as high as 610 mAh g−1. The excellent electrochemical performance is attributed to the moderate composition, spherical morphology and unique microstructure of the synthesized material.

Multi-layered composite electrodes of high power Li4Ti5O12 and high capacity SnO2 for smart lithium ion storage

Discrete layering of high power Li4Ti5O12 and high capacity SnO2 in a through-thickness multi-layered composite electrode was achieved using a layer-by-layer spray printing approach in order to explore new capacity-power combinations for lithium ion based electrochemical energy storage. Electrochemical behavior of multi-layered electrodes was optimized as a function of the thickness of the discrete SnO2 layer, in the range 2 to 6 µm, interleaved between two layers of low volume expansion Li4Ti5O12. Three discrete layers of 2 µm SnO2 were then interleaved evenly between Li4Ti5O12 layers to produce a “layer cake” negative electrode cross-section that offered remarkable rate capability when coupled with a spray printed LiFePO4 positive electrode in a lithium ion battery arrangement. The multi-layered negative electrode was also coupled with a spray printed activated carbon positive electrode in a lithium ion capacitor configuration, providing significant improvements in energy density. The double-sided fabrication of the multi-layer electrode over a 20 × 20 cm2 current collector area suggested a possible hybrid electrochemical device that combines attributes of high capacity lithium ion batteries and high power lithium ion capacitors.

Coupled electrochemical-mechanical modeling with strain gradient plasticity for lithium-ion battery electrodes

We first present a model coupling the electrochemical reaction with strain gradient plasticity for a spherical electrode, which aims to analyze the evolutions and distributions of electrochemical-reaction dislocations and diffusion-induced stress during lithiation process. Several critical features viewed by in-situ TEM are incorporated into this model, such as the two-phase boundary and high-density dislocations at the reaction front. It is shown that the microstructure evolution can impact the mechanical properties and electrochemical performances of electrode materials. The results obtained by a finite difference method indicate that, as lithiation proceeds, the circumferential stress on the surface of the lithiated shell changes from compression to tensile stress, which may cause fracture of the active materials. Especially, the electrochemical-reaction dislocation zone results in fairly large stresses at the front of the interface. Furthermore, the lithiation reaction displays a strong size effect, and the movement rate of reaction front reduces as the size of the particles decreases. This work provides a framework for large-capacity, multi-scale research on high-capacity lithium-ion battery electrodes.

Eco-friendly Synthesis of Nanoporous Magnesium by Air-Free Electrolytic Dealloying with Recovery of Sacrificial Elements for Energy Conversion and Storage Applications

The synthesis of nanoporous Mg with minimal surface oxide coverage has been hindered by its high chemical reactivity. Herein, we demonstrate the fabrication of three-dimensional bicontinuous nanoporous Mg with ligament and pore sizes in the range of 20–30 nm using air-free electrolytic dealloying with recovery of the sacrificial material. The starting material consists of a magnesium–lithium parent alloy with lithium as the sacrificial component. During selective electrolytic leaching in an anhydrous lithium-conducting organic electrolyte solvent, the sacrificial lithium is stripped from the magnesium–lithium parent alloy used as the working electrode and plated on a pure lithium foil used as the counter electrode, enabling sacrificial element recovery, making the process eco-friendly. The morphology of the fabricated nanoporous Mg was thoroughly investigated using electron microscopy techniques, inductively coupled plasma (ICP) spectroscopy, X-ray photoelectron spectroscopy (XPS), small-angle X-ray scattering (SAXS), and X-ray diffraction. The synthesized nanoporous Mg is attractive for energy conversion and storage applications. Here, we show that it can produce hydrogen on-demand by hydrolysis with pure water and that it can also be used as a high-capacity lithium-ion battery anode.

Two-dimensional MnN utilized as high-capacity anode for Li-ion batteries* *Project supported by the Scientific Research Fund of Jiangxi Provincial Education Department, China (Grant No. GJJ190962), the National Natural Science Foundation of China (Grant Nos. 11904153, 51962010, 61961027, 12064026, and 12064014), and Jiangxi Province Natural Science Foundation, China (Grant No. 20202BABL211008).

When developing high performance lithium-ion batteries, high capacity is one of the key indicators. In the last decade, the progress of two-dimensional (2D) materials has provided new opportunities for boosting the storage capacity. Here, based on first-principles calculation method, we predict that MnN monolayer, a recently proposed 2D nodal-loop half-metal containing the metallic element Mn, can be used as a super high-capacity lithium-ion batteries anode. Its theoretical capacity is above 1554 mA⋅h/g, more than four times that of graphite. Meanwhile, it also satisfies other requirements for a good anode material. Specifically, we demonstrate that MnN is mechanically, dynamically, and thermodynamically stable. The configurations before and after lithium adsorption exhibit good electrical conductivity. The study of Li diffusion on its surface reveals a very low diffusion barrier (∼ 0.12 eV), indicating excellent rate performance. The calculated average open-circuit voltage of the corresponding half-cell at full charge is also very low (∼ 0.22 V), which facilitates higher operating voltage. In addition, the lattice changes of the material during lithium intercalation are very small (∼ 1.2%–∼ 4.8%), which implies good cycling performance. These results suggest that 2D MnN can be a very promising anode material for lithium-ion batteries.

Surface Oxidation Layer-Mediated Conformal Carbon Coating on Si Nanoparticles for Enhanced Lithium Storage.

Si is a well-known high-capacity lithium-ion battery anode material; however, it suffers from conductivity and volume expansion issues. Herein, we develop a "surface oxidation" strategy to introduce a SiOx layer on Si nanoparticles for subsequent carbon coating. It is found that the surface SiOx layer could facilitate the conformal resin coating process through strong interactions with phenolic resin, and well-defined core@double-shell-structured Si@SiOx@C can be obtained after further carbonization. Without the surface SiOx layer, only a negligible fraction of Si nanoparticles can be encapsulated into the carbon matrix. With enhanced conductivity and confined volume change, Si@SiOx@C demonstrates high reversible capacity as well as long-term durability.

Porous hydrogen substituted graphyne as a promising anode for lithium-ion batteries.

Porous hydrogen substituted graphyne (HsGY) has been considered as a promising candidate for anode material due to its excellent electrochemical properties. In this work, we found that monolayer and bilayer HsGY are good electrodes for high charge capacity lithium-ion batteries based on density functional theory calculations. Mechanical tests reveal that monolayer and bilayer HsGY exhibit excellent mechanical properties, including large critical strains (>25%) and high in-plane stiffness (>200 N m−1). The bilayer HsGY displays ultrahigh stiffness (400.27 N m−1). Li adsorption on bilayer HsGY is stronger than that on the monolayer HsGY. Moreover, Li diffusion on the surfaces of monolayer and bilayer HsGY has low energy barriers (<0.5 eV). Our calculation results suggest that HsGY may contain the highest theoretical charge capacity among two-dimensional (2D) materials studied so far, with ultrahigh Li capacities of 3378 and 2895 mA h g−1 for monolayer and bilayer HsGY, respectively. Given these advantages, including large critical strain, high mechanical stiffness, strong adsorption, low diffusive energy barrier, and high charge capacity, we conclude that both monolayer and bilayer HsGY could be promising anode materials for lithium-ion batteries.

A perylene-based aromatic polyimide with multiple carbonyls enabling high-capacity and stable organic lithium and sodium ion batteries

We have synthesized a perylene-based aromatic polyimide (PI) through the polycondensation of perylene dianhydride with a 2,6-DAAQ. The battery cells with the PI cathode exhibited high discharge capacities of 209 mA h g−1 (Li+/Li) and 207 mA h g−1 (Na+/Na) at 200 mA g−1.

Sustainable bio-derived materials for addressing critical problems of next-generation high-capacity lithium-ion batteries

Sustainable bio-derived materials solve the critical issues of low ionic and electrical conductivity, large volume variation, lithium dendrite formation, and the shuttle effect of the sulfur cathode in lithium-ion batteries.

Composites of Silicon@Li4Ti5O12 and Graphite for High-Capacity Lithium-Ion Battery Anode Materials

Silicon (Si) is a promising anode material for lithium-ion batteries owing to its high theoretical capacity. However, it suffers from poor capacity retention during cycling due to mechanical stresses, pulverization, and an unstable solid electrolyte interface. One practical approach to mitigate the problem is a coating design, where nano-sized silicon is encapsulated within a selected protective layer. In this study, silicon nanoparticles have been coated with a protective layer of Li4Ti5O12 (LTO) ceramic and prepared using a water-based sodium alginate binder. It is found that the Si@LTO composites can be combined with graphite to improve battery performance further. The composite electrodes have been tested in half cells at C/10 and 1C rates. The best Si@LTO and graphite composite has an initial high capacity (∼900 mAh g−1 at C/10 and ∼600 mAh g−1 at 1C) and good capacity retention. It is found that this capacity retention is superior to Si@LTO alone and a binary composite of silicon with graphite. These Si@LTO + graphite composites are a promising way to integrate silicon into the development of stable and high-energy-density lithium-ion batteries.

Interlayer spacing engineering in N doped MoS2 for efficient lithium ion storage

MoS2 has been intensively studied as a promising anode material for high capacity lithium ion batteries (LIBs), which is strongly limited by its poor cycling stability and inferior rate performance. In this work, the strategy of interlayer spacing engineering is applied on MoS2 to effectively expand the interlayer spacing from 0.62 nm to 0.98 nm, with the addition of ւ-cysteine during hydrothermal process. The cycling stability is significantly improved. The composites of interlayer expanded MoS2 and graphene oxide are further treated by N plasma to effectively dope N into both reduce graphene oxide and MoS2. The final product exhibits outstanding electrochemical performance as anode in LIBs, with high reversible capacity of 643 mA h·g−1 after 400 cycles at the rate of 500 mA g−1 and excellent rate capacity of 580 mA h·g−1 up to the rate of 2000 mA g−1. This work demonstrates that proper nanostructure engineering and electronic structure modification can make MoS2 a promising electrode material in highly fast and stable energy storage applications.