High-energy Lithium-ion Batteries Research Articles

Co[sbnd]Fe hydroxyoxalate nanosheets chemically bonded with reduced graphene oxide as High-performance anode for lithium-ion batteries

Transition metal layered double hydroxide (LDHs) materials are promising anodes for high-energy lithium-ion batteries (LIBs) due to their high specific capacities. However, the conductivity and the influence of intercalated anions are key issues for improving their electrochemical performances. Herein, a C2O42− intercalated CoFe-LDH nanosheets anchored on reduced graphene oxide (Co0.83Fe0.17(OH)2(C2O4)0.085·0.08H2O/rGO, CFO) composite was successfully synthesized for the first time by a two-step hydrothermal process. Graphene provides abundant nucleation sites for CoFe-LDH and forms the interconnected porous network skeleton. The intercalated C2O42− ions widen the interlayer spacing of CoFe-LDH to 0.92 nm, which can enhance the transportation of lithium ions. The lithium storage mechanism was proved that the CFO was transformed into a heterostructure nanocomposite (metal hydroxide and lithium oxalate) after discharge, and the high-valent carbon in lithium oxalate was electrocatalytically converted into low-valent carbon. This results in fast electrochemical reactions and high capacity. What’s more, the CFO shows a high reversible capacity (1603 mAh g−1 after 120 cycles), and long-term cycle stability under high current density (CFO delivers a reversible capacity of 860 mAh·g−1 after 1000 cycles at 4 A·g−1). This work provides a new anodes material for application in high-energy LIBs.

Thermal-healing of lattice defects for high-energy single-crystalline battery cathodes

Single-crystalline nickel-rich cathodes are a rising candidate with great potential for high-energy lithium-ion batteries due to their superior structural and chemical robustness in comparison with polycrystalline counterparts. Within the single-crystalline cathode materials, the lattice strain and defects have significant impacts on the intercalation chemistry and, therefore, play a key role in determining the macroscopic electrochemical performance. Guided by our predictive theoretical model, we have systematically evaluated the effectiveness of regaining lost capacity by modulating the lattice deformation via an energy-efficient thermal treatment at different chemical states. We demonstrate that the lattice structure recoverability is highly dependent on both the cathode composition and the state of charge, providing clues to relieving the fatigued cathode crystal for sustainable lithium-ion batteries.

Knitting a sweater with UV-induced in situ polymerization of poly(pyrrole-co-citral nitrile) on Ni-rich layer oxide cathode materials for lithium ion batteries

Ni-rich layered oxide (LiNi0.8Co0.1Mn0.1O2) has become popular commercial cathode material for lithium ion batteries, due to its high working potential and high specific capacity. It is still a challenge, however, to maintain the structure and performance under extreme conditions, such as at high charging cutoff (≥4.5 V), high temperature (≥60 °C) and higher charge-discharge rate (≥3 C). Herein, Poly (pyrrole-co-citral nitrile) (PPC) optimized interfacial layer is designed and constructed on the surface of LiNi0.8Co0.1Mn0.1O2 by an in situ photopolymerization self-assembly technology. The sweater-like co-polymer coating provides an integral protection from side reaction, particle rupture and irreversible phase transition during cycling under the extreme conditions. Furthermore, the delocalized π bonds and cross-linked network structure of the co-polymer coating ensure the efficient and stable interface between electrolyte and electrode. This work offers a novel and useful strategy to enhance the electrochemical performance of Ni-rich cathode materials for high-energy lithium ion batteries at extreme conditions.

To Pave the Way for Large-Scale Electrode Processing of Moisture-Sensitive Ni-Rich Cathodes

High-capacity Ni-rich cathode such as LiNi0.8Mn0.1Co0.1O2 (NMC811) has a great potential to enable high energy lithium-ion batteries (LIBs) for long-range electrical vehicles. However, the utilization of NMC 811 in large-scale application is still challenging. While many published papers on NMC811 focus on materials modification, the moisture sensitivity of NMC811 and its implications in storage and large-scale electrode coating are not well explored, not to mention how to overcome those challenges for industry application. This work discusses the key parameters impacting the rheological properties of NMC811 slurries and their correlations to the properties of dried electrodes. Effective solutions are proposed to address the gelation issue of NMC811 slurry during large-scale coating to hopefully inspire more effective and practical approaches to tackle the grand challenges in electrochemical energy storage.

Graphene coating on silicon anodes enabled by thermal surface modification for high-energy lithium-ion batteries

Graphene coating on silicon anodes enabled by thermal surface modification for high-energy lithium-ion batteries

Novel equivalent circuit model for high-energy lithium-ion batteries considering the effect of nonlinear solid-phase diffusion

Efficient and accurate management of lithium-ion batteries (LIBs) highly relies on models that capture the in-cell nonlinear behaviors. As one of the most dominant dynamics inside high-energy LIBs, the solid-phase diffusion shows nonlinearity because the lithium diffusivity in solid phase is a physical parameter varying with the lithium concentration. Yet, this nonlinearity has not been well disclosed in the electrical modeling field of LIBs. This paper presents a novel equivalent circuit model in which the effect of nonlinear solid-phase diffusion is considered. First, the modeling process is illustrated, and it is worth noting that the circuit representation of solid-phase diffusion is established based on its physical principles at electrode particle level. Second, while paying special attention to the relaxation voltage offset, the model parameters are identified with the help of the multi-timescale characteristics of batteries during the voltage recovery period in pulse discharge test. Finally, the model is thoroughly validated by performing constant-current discharge and dynamic tests on the commercial high-energy LIBs. Results show that the proposed model remains robust to the state-of-health of batteries and outperforms the conventional second-order resistor–capacitor model. Moreover, the model keeps similar simplicity to the conventional one and can meet the real-time requirements in engineering.

Modeling and synthesis of carbon-coated LiMnPO4 cathode material: Experimental investigation and optimization using response surface methodology

Nanostructured LiMnPO4 cathode materials for lithium-ion batteries (LIBs) have been successfully prepared by a modified solvothermal method under controlled conditions. Polyethylene glycol (PEG-10000) was used as a solvent to optimize the particle size/mor­phology and as a carbon conductive matrix. In order to investigate the effect of synthesis parameters such as concentration of PEG-10000, reaction time and reaction temperature on the LiMnPO4 phase purity, Response surface methodology was carried out to find variations in purity results across the composition. The purity of all materials was checked using HighScore software by comparing the matched lines score to ones of reference data. As a result, it has been found that the pure phospho-olivine material LiMnPO4 can be syn­thesized using the following optimum conditions: PEG concentration = 0.1 mol l-1, reaction time = 180 min, and reaction temperature = 250 °C. The as-prepared LiMnPO4 under opti­mum conditions delivered an initial discharge capacity of 128.8 mAh g-1 at 0.05 C‑rate. The present work provides insights and suggestions for optimizing synthesis conditions of this material, which has been considered the next promising cathode candidate for high-energy lithium-ion batteries.

Designing Versatile Polymers for Lithium-Ion Battery Applications: A Review.

Solid-state electrolytes are a promising family of materials for the next generation of high-energy rechargeable lithium batteries. Polymer electrolytes (PEs) have been widely investigated due to their main advantages, which include easy processability, high safety, good mechanical flexibility, and low weight. This review presents recent scientific advances in the design of versatile polymer-based electrolytes and composite electrolytes, underlining the current limitations and remaining challenges while highlighting their technical accomplishments. The recent advances in PEs as a promising application in structural batteries are also emphasized.

Local ionic structure unit design in sulfide solid electrolyte flakes by improving pressing process

The rapid development of electric vehicles and energy storage facilities requires novel secondary batteries with higher energy density and increased safety. Sulfide solid electrolyte, especially lithium thiophosphate (LPS), has become a research hotspot due to its non-flammability and high structural strength. The high-performance LPS powders need to be prepared into flakes before practical application. However, the widely used cold pressing process for the preparation of LPS flakes have fatal defects such as low density and high interface resistance. This work systematically studied the differences in the body defects, density and crystallization process of electrolyte flakes obtained by different tableting processes. The nucleation is inhibited in the high-density sulfide solid electrolyte samples. In addition, based on the improvement of pressurizing equipment, it was discovered for the first time that glass transition process (the secondary hot pressing at glass transition temperature) can significantly improve the distribution of local structured ions. Notably, the content of P2S74- and P2S64- has doubled after glass transition, resulting in improving the ionic conductivity and stability, respectively. The HP-GT (the electrolyte flakes after glass transition) exhibits extremely high relative density (99 ± 1%), low ion activation energy (14.4 kJ/mol) and extremely high ion conductivity (3.48 mS/cm). On the other hand, a specific discharge capacity of ∼ 680 mAh g−1 is still maintained for the Li|HP-GT|MoS2 solid-state battery after 30 cycles. This work confirms the feasibility of the sulfide solid electrolyte after the second hot-pressing in the application of high-safety, high-energy density solid-state lithium batteries.

Elastomeric electrolytes for high-energy solid-state lithium batteries.

The use of lithium metal anodes in solid-state batteries has emerged as one of the most promising technologies for replacing conventional lithium-ion batteries1,2. Solid-state electrolytes are a key enabling technology for the safe operation of lithium metal batteries as they suppress the uncontrolled growth of lithium dendrites. However, the mechanical properties and electrochemical performance of current solid-state electrolytes do not meet the requirements for practical applications of lithium metal batteries. Here we report a class of elastomeric solid-state electrolytes with a three-dimensional interconnected plastic crystal phase. The elastomeric electrolytes show a combination of mechanical robustness, high ionic conductivity, low interfacial resistance and high lithium-ion transference number. The in situ-formed elastomer electrolyte on copper foils accommodates volume changes for prolonged lithium plating and stripping processes with a Coulombic efficiency of 100.0percent. Moreover, the elastomer electrolytes enable stable operation of the full cells under constrained conditions of a limited lithium source, a thin electrolyte and a high-loading LiNi0.83Mn0.06Co0.11O2 cathode at a high voltage of 4.5volts at ambient temperature, delivering a high specific energy exceeding 410watt-hours per kilogram of electrodepluselectrolyte. The elastomeric electrolyte system presents a powerful strategy for enabling stable operation of high-energy, solid-state lithium batteries.

Tunable surface pseudocapacitance assisted fast and flexible lithium storage of graphene wrapped NiO nano-arrays on nitrogen-doped carbon foams

Advanced materials incorporating battery-like high capacity and capacitor-like high rate capability hold promise for achieving both high energy and power density lithium ion batteries (LIBs). However, capacitive behavior for high capacity NiO anode has seldom been reported because the surface or near-surface fast faradic surface redox reactions highly depends on specific structure design. Herein, a flexible electrode that graphene wrapped NiO nanosheet arrays anchor on three-dimensional porous nitrogen-doped carbon foam (rGO@NiONCF) is fabricated. The rGO@NiONCF composite possesses a unique sandwich structure with 3D porous NCF as the inner conductive scaffold, ultrathin NiO nanosheet arrays as a middle layer, and rGO as the outer conductive buffer layer. The elaborated structure design endows rGO@NiONCF with enhanced electronic conductivity, sufficient electrolyte infiltration and restricted volume variation. As a result, the rGO@NiONCF electrode delivers high reversible capacity (1583 mAh g−1 at 0.1 A g−1) and superior cycling stability (maintains 607 mA h g−1 at 1 A g−1 after 500 cycles). Moreover, the enhanced surface capacitance adroitly facilitates an impressive fast charge and slow discharge performance. These results reveal that rational material design to encourage pseudocapacitance effect is a valuable roadmap for NiO-based battery towards more practical applications.

Aqueous electrolyte with moderate concentration enables high-energy aqueous rechargeable lithium ion battery for large scale energy storage

The intrinsic safe and environmentally friendly aqueous rechargeable lithium ion battery (ARLIB) is a promising candidate for large scale energy storage system application. However, the low energy density and limited cycle life hamper its practical application. Here, a deep eutectic electrolyte composed of LiClO4·3H2O and urea with a moderate concentration of 5 M is explored, in which the population of free water molecules is depleted leading to the expanded electrochemical stability window to ∼3.2 V. In addition, the diminished population of free water suppresses the anodic Al dissolution. Combining with graphene coating, the Al current collector exhibits strong corrosion resistant. A Li4Ti5O12/LiMn2O4 battery of 2.2 V using such electrolyte and current collector delivers cycle life up to 1000 times and a high energy density of 135 Wh kg−1. The results open a new avenue to advance high-energy ARLIB, contributing to the low cost and grid-scale energy storage applications.

Dealloying of modified Al-Si alloy to prepare porous silicon as Lithium-ion battery anode material

ABSTRACT Silicon plays an important role in the development of high-energy Lithium-ion batteries. However, the high volume expansion rate (>300%) makes it a commercially unfeasible independent Lithium-ion battery anode material. In this work, we adopt P and Sr complex modification and increase the cooling rate to refine the microstructure of Casting Al-20Si alloy, then acid etching Al-20Si alloy ingot to prepare porous silicon. The as-prepared silicon has a three-dimensional dendritic porous structure based on the SEM morphology characterization. The porous silicon electrode was prepared with Si powder: acetylene black: binder in a ratio of 2:1:1. The electrolyte solution was 1 M LiPF6/EC:EMC: DMC = 1:1:1 (V/V) with or without 5% FEC. In the electrolyte solution without 5% FEC, the first charge and discharge capacities of the porous silicon electrode are 2924.8 mAh/g and 1910.1 mAh/g, and the coulombic efficiency is about 65.31%. In the electrolyte solution with additive 5% FEC, the first charge and discharge capacities are 3444.6 mAh/g and 2469.5 mAh/g, respectively. Its first cycle coulombic efficiency is 72.19%. After adding 5% FEC into the electrolyte, the main component of SEI film is the decomposition product of FEC, which can effectively inhibit the decomposition of electrolyte solvent at a low potential and improve the specific capacity of the battery.

Calendar Aging of Ni-Rich Cathode in High-Energy Lithium-Ion Batteries

Calendar Aging of Ni-Rich Cathode in High-Energy Lithium-Ion Batteries

Studies on Synthesis and Electrochemical Properties of Lithium Ferrous Silicate Cathode Materials

The lithium ferrous silicate (Li₂FeSiO₄) has high theoretical capacity of 330 mAh/g, abundant raw material resources, stable working voltage, excellent thermal stability of Si-O bond, environmental protection and low cost, and has become one of the attractive cathode materials in high-energy lithium batteries. However, the conductivity of Li₂FeSiO₄ material itself is poor, and the ionic conductivity is low, so improving the conductivity and Li⁺ diffusion coefficient of the material has become the focus of research. In this paper, Li₂FeSiO₄ material was synthesized by the combination of sol-gel method and solid-state sintering method, and the nano-material and metal ion doping were realized by liquid-phase grinding method, which increased the specific surface area and conductivity of the material and increased the specific energy of the material. XRD, TGDSC, particle size analysis and electrochemical capacity test show that the specific capacity of the initial Li₂FeSiO₄ material synthesized in solid phase is 120 mAh/g, and the capacity of the nano-treated Li₂FeSiO₄ material reaches 140mah/g; The Li₂Fe_0.5Mn_0.5SiO₄ material obtained by Mn doping has a capacity of 160mah/g; The volume of Li₂Fe_0.5Mn_0.45Ti_0.05SiO₄ synthesized by adding metal Ti is increased to 195mah/g; The electrical conductivity of Li₂Fe_0.5Mn_0.5Si_0.975V_0.025O₄+C synthesized by doping v and c can be significantly improved, and the discharge capacity can reach about 200mAh/g. In the liquid phase grinding of the mixture of ethanol and acetone, it was found that the tautomers of alcohol and ketone were in the dynamic equilibrium of ketone and enol, and acetone met positively charged metal ions to form stable metal salts, which improved the stability of the material.

Crack-free single-crystalline Co-free Ni-rich LiNi0.95Mn0.05O2 layered cathode

The rapid growth in global electric vehicles (EVs) sales has promoted the development of Co-free, Ni-rich layered cathodes for state-of-the-art high energy-density, inexpensive lithium-ion batteries (LIBs). However, progress in their commercial use has been seriously hampered by exasperating performance deterioration and safety concerns. Herein, a robust single-crystalline, Co-free, Ni-rich LiNi0.95Mn0.05O2 (SC-NM95) cathode is successfully designed using a molten salt-assisted method, and it exhibits better structural stability and cycling durability than those of polycrystalline LiNi0.95Mn0.05O2 (PC-NM95). Notably, the SC-NM95 cathode achieves a high discharge capacity of 218.2 mAh g−1, together with a high energy density of 837.3 ​Wh kg−1 ​at 0.1 C, mainly due to abundant Ni2+/Ni3+ redox. It also presents an outstanding capacity retention (84.4%) after 200 cycles at 1 ​C, because its integrated single-crystalline structure effectively inhibits particle microcracking and surface phase transformation. In contrast, the PC-NM95 cathode suffers from rapid capacity fading owing to the nucleation and propagation of intergranular microcracking during cycling, facilitating aggravated parasitic reactions and rock-salt phase accumulation. This work provides a fundamental strategy for designing high-performance single-crystalline, Co-free, Ni-rich cathode materials and also represents an important breakthrough in developing high-safe, low-cost, and high-energy LIBs.

Optimization of Hybrid Energy Management System Based on High-Energy Solid-State Lithium Batteries and Reversible Fuel Cells

Optimization of Hybrid Energy Management System Based on High-Energy Solid-State Lithium Batteries and Reversible Fuel Cells

A Scalable Silicon/Graphite Anode with High Silicon Content for High-Energy Lithium-Ion Batteries

A Scalable Silicon/Graphite Anode with High Silicon Content for High-Energy Lithium-Ion Batteries

Effect of Moo3 Coating on the Electrochemical Performance of Lini0.8co0.1mn0.1o2 Cathode for High-Energy Lithium-Ion Batteries

Effect of Moo3 Coating on the Electrochemical Performance of Lini0.8co0.1mn0.1o2 Cathode for High-Energy Lithium-Ion Batteries

Controllable Synthesis of Silicon/Carbon Microspheres Alternating Carbon and Silicon Shells for High-Energy Lithium-Ion Batteries

Controllable Synthesis of Silicon/Carbon Microspheres Alternating Carbon and Silicon Shells for High-Energy Lithium-Ion Batteries