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LiNi0.5Mn1.5O4 (LNMO) with a spinel crystal structure presents a compelling avenue towards the development of economic cobalt-free and high voltage (∼ 5 V) lithium-ion batteries. Nevertheless, the elevated operational voltage of LNMO gives rise to pronounced interfacial interactions between the distorted surface lattices characterized by Jahn–Teller (J–T) distortions and the electrolyte constituents. Herein, a localized crystallized coherent LaNiO3 and surface passivated Li3PO4 layer is deposited on LNMO via a one-step calcination process. As evidenced by transmission electron microscopy (TEM), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and density functional theory (DFT) calculation, the epitaxial growth of LaNiO3 along the LNMO lattice can effectively stabilize the structure and inhibit irreversible phase transitions, and the Li3PO4 surface coating can prevent the chemical reaction between HF and transition metals without sacrificing the electrochemical activity. In addition, the ionic conductive Li3PO4 and atomic wetting inter-layer enables fast charge transfer transport property. Consequently, the LNMO material enabled by the lattice bonding and surface passivating features, demonstrates high performance at high current densities and good capacity retention during long-term test. The rational design of interface coherent engineering and surface coating layers of the LNMO cathode material offers a new perspective for the practical application of high-voltage lithium-ion batteries. [ABSTRACT FROM AUTHOR]

SiO–based materials are promising alloys and conversion‐type anode materials for lithium‐ion batteries and are recently found to be excellent dendrite‐proof layers for lithium‐metal batteries. However, only a small fraction of the Li–Si–O compositional space has been reported, significantly impeding the understanding of the phase transition mechanisms and the rational design of these materials both as anodes and as protection layers for lithium‐metal anodes. Herein, we identify three new thermodynamically stable phases within the Li–Si–O ternary system (Li2SiO5, Li4SiO6, and Li4SiO8) in addition to the existing records via first‐principle calculations. The electronic structure simulation shows that Li2SiO5 and Li4SiO8 phases are metallic in nature, ensuring high electronic conductivity required as electrodes. Moduli calculations demonstrate that the mechanical strength of Li–Si–O phases is much higher than that of lithium metal. The diffusion barriers of interstitial Li range from 0.1 to 0.6 eV and the interstitial Li hopping serves as the dominating diffusion mechanism in the Li–Si–O ternary systems compared with vacancy diffusion. These findings provide a new strategy for future discovery of improved alloying anodes for lithium‐ion batteries and offer important insight towards the understanding of the phase transformation mechanism of alloy‐type protection layers on lithium‐metal anodes. [ABSTRACT FROM AUTHOR]

Li-ion batteries are a key technology for addressing the global challenge of clean renewable energy and environment pollution. Their contemporary applications, for portable electronic devices, electric vehicles, and large-scale power grids, stimulate the development of high-performance battery materials with high energy density, high power, good safety, and long lifetime. High-throughput calculations provide a practical strategy to discover new battery materials and optimize currently known material performances. Most cathode materials screened by the previous high-throughput calculations cannot meet the requirement of practical applications because only capacity, voltage and volume change of bulk were considered. It is important to include more structure-property relationships, such as point defects, surface and interface, doping and metal-mixture and nanosize effects, in high-throughput calculations. In this review, we established quantitative description of structure-property relationships in Li-ion battery materials by the intrinsic bulk parameters, which can be applied in future high-throughput calculations to screen Li-ion battery materials. Based on these parameterized structure-property relationships, a possible high-throughput computational screening flow path is proposed to obtain high-performance battery materials. [ABSTRACT FROM AUTHOR]

Abstract: The electronic structures of Mg-doped LiCoO2 have been investigated by the first-principle pseudopotential method. The effect of Mg-doping content on the band structure and structural stability of LiCoO2 is presented. The results obtained via a full relaxation of the crystalline structure show that a rational amount of Mg-doping in LiCoO2 is helpful to enhance its electronic conductivity. However, the doping magnitude should be controlled within 15mol% of LiCoO2 in order to keep its crystalline structure unchanged. By combining total energy calculations with basic thermodynamics, the average intercalation voltages of this doped system have been predicted. [Copyright &y& Elsevier]

Abstract: Monoclinic Li2CO3 has been identified as a critical component of the solid electrolyte interphase (SEI), a passivating film that forms on Li-ion battery anode surfaces. Here, lattice dynamics, finite temperature thermodynamics and the elastic properties of monoclinic Li2CO3 are examined with density functional theory (DFT) and various exchange–correlation functionals. To account for LO-TO splittings in phonon dispersion relations of Li2CO3, which is a polar compound, a mixed-space phonon approach is employed. Bond strengths between atoms are quantitatively explored with phonon force constants. Temperature variations of the entropy, enthalpy, isobaric heat capacity and linear (average) thermal expansion are computed using the quasiharmonic approach. The single-crystal elasticity tensor components along with polycrystalline bulk, shear and Young’s moduli are computed with a least-squares approach based upon the stress tensor computed from DFT. Computed thermodynamic properties as well as structural and elastic properties of the monoclinic Li2CO3 are in close accord with available theoretical and experimental data. In contrast to a recent DFT study, however, computed vibrational spectra suggest that neither the monoclinic Li2CO3 nor its high-temperature hexagonal phase exhibits either elastic or vibrational instabilities. [Copyright &y& Elsevier]

Using first-principles calculations, we have systematically investigated the adsorption and diffusion behavior of Li in MoO 3 bulk, on MoO 3 (010) surface and in MoO 3 /graphene composite. Our results indicate that, in case of MoO 3 bulk, Li diffusion barriers in the interlayer and intralayer spaces are 0.55 eV and 0.58 eV respectively, which are too high to warrant fast Lithium-ion charge/discharge processes. While on MoO 3 (010) surface, Li exhibits a diffusion barrier as low as 0.07 eV which guarantees an extremely fast Li diffusion rate during charge/discharge cycling. However, in MoO 3 /graphene monolayer, Li diffusion barrier is at the same level as that on MoO 3 (010) surface, which also ensures a very rapid Li charge/discharge rate. The rapid Li charge/discharge rate in this system originates from the removal of the upper dangling O1 atoms which hinder the Li diffusion on the lower MoO 3 layer. Besides this, due to the interaction between Li and graphene, the Li average binding energy increases to 0.14 eV compared to its value on MoO 3 (010) surface which contributes to a higher voltage. Additionally, the increased ratio of surface area provides more space for Li storage and the capacity of MoO 3 /graphene composite increases up to 279.2 mAhg −1 . The last but not the least, due to the high conductivity of graphene, the conductivity of MoO 3 /graphene composite enhances greatly which is beneficial for electrode materials. In the light of present results, MoO 3 /graphene composite exhibits higher voltage, good conductivity, large Li capacity and very rapid Li charge/discharge rate, which prove it as a promising cathode material for high-performance lithium-ion batteries (LIBs). [ABSTRACT FROM AUTHOR]

Polyethylene oxide (PEO) based materials are promising candidates for the matrices in composite solid polymer electrolytes (CSPEs) for high-energy density lithium ion batteries. Experimental screening of high-performance CSPEs with high efficiency still appears to be challenging for the moment, due to the complications of the compositions involved. Here, we propose and test the joint application of effective medium theory (EMT) and Halpin-Tsai model that can predict with satisfactory accuracy the effects of the filler volume fractions and of the particle sizes on the conductivities and Young’s moduli of CSPEs. The application of this theoretical framework can be extended to other polymer based CSPEs and potentially enables us to build a CSPEs database for data mining to accelerate the screening process. [ABSTRACT FROM AUTHOR]

The ion-intercalation-based rechargeable batteries are emerging as the most efficient energy storage technology for electronic vehicles, grids, and portable devices. These devices require rechargeable batteries with higher energy–density than commercial Li-ion batteries, which are intrinsically limited by specific capacities and electrochemical potentials of transition-metal (M) electrode materials. Over the past decades, a significant number of studies have focused on exploring coordination environments and electronic origins of these materials based on ligand field theory (LFT). However, studies to understand and manipulate the relationship between their local-structural characteristics and electrochemical properties are limited. In this review, we comprehensively discussed how the combining of LFT and first-principles calculations can be used to derive Fermi levels that determine electrochemical potential, crystal field stabilization energy, and anionic redox activity. Based on this, a series of strategies are proposed to improve the phase-stability and energy–density of intercalation-type electrode materials, such as ion-intercalation potential tuning of rigid-band systems and electrode phase stability regulations with different M periods. Two high energy–density cathode materials, M -free LiBCF 2 and Li-free group-VB/VIB MX 2 (X = S, Se), are successfully designed from the aforementioned principles derived. Finally, we also highlight further directions for designing better intercalation-type materials based on LFT and their opportunities/challenges. [ABSTRACT FROM AUTHOR]

Developing rechargeable lithium ion batteries with fast charge/discharge rate, high capacity and power, long lifespan, and broad temperature adaptability is still a significant challenge. In order to realize the fast and efficient transport of ions and electrons during the charging/discharging process, a pure and well-crystallized LiMn 0.8 Fe 0.2 PO 4 cathode material is directly synthesized via co-precipitation method at ambient pressure and 130 °C. Nano-LiMn 0.8 Fe 0.2 PO 4 /C with 5.7 wt% conductive carbon delivers a discharge capacity of 160.6 mAh g −1 at 0.05 C, close to the theoretical value (170 mAh g −1 ). Even at 10 C, 20 C and 50 C, stable capacities of 113 mAh g −1 , 102 mAh g −1 and 83 mAh g −1 are obtained, respectively. The discharge capacity at −15 °C is as high as 97 mAh g −1 at 0.1 C. The excellent high-rate and low-temperature performances of nano-LiMn 0.8 Fe 0.2 PO 4 /C effectively promote its practical usage in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

LiMnPO4/C, LiMn0.8Fe0.2PO4/C, and corresponding composites with nominal formula of 0.8LiMnPO4·0.2Li3V2(PO4)3/C and 0.8LiMn0.8Fe0.2PO4·0.2Li3V2(PO4)3/C are synthesized via high temperature solid-state reaction. According to refinement results, the phase ratios of olivine and NASICON in 0.8LiMnPO4·0.2Li3V2(PO4)3/C and 0.8LiMn0.8Fe0.2PO4·0.2Li3V2(PO4)3/C are 84.2:15.8 and 81.2: 18.8, respectively. Complexing Li3V2(PO4)3 plays negligible influence on discharge capacity when cycled between 2.5 and 4.4V vs. Li+/Li. Instead, this strategy significant improves the rate capability of phosphate composites. The discharge capacities of composites at 2C are 103.8 and 117.6mAhg−1, which are much higher than those of corresponding olivine counterparts, namely 35.3 and 91.1mAhg−1. [ABSTRACT FROM AUTHOR]

[Display omitted] • A Li 3 PO 4 -LiNiPO 4 bifunctional dual-layer coating is utilized to modify Ni-rich cathode. • Each layer is designed to function differently. • This dual-layer coating is formed through a one-step solid–gas reaction. • The modified sample exhibits superior electrochemical performance. Ni-rich Li[Ni x Co y Mn 1-x-y ]O 2 (NCM, x > 0.6) is a promising cathode material for lithium-ion batteries while disadvantages like rapid capacity fading and poor rate performance hinder its practical application. In this work, a dual-layer coating is designed and utilized through a solid–gas reaction between the cathode particles and gaseous P 2 O 5 , where Li 3 PO 4 acts as a protecting layer against acid attack and LiNiPO 4 as a fast ion-conducting layer. The modified sample (LL-NCM94) exhibits a much higher capacity retention of 89.6% after 100 cycles at 1C between 2.8 and 4.3 V in comparison with the capacity retention of 65.9% for pristine sample (P-NCM94). Under the high C-rate of 5C and 10C, the discharge capacity of LL-NCM94 is 20% and 45% higher than P-NCM94, respectively. The better electrochemical performance of LL-NCM94 is attributed to the dual-layer coating in which each layer functions differently and simultaneous elimination of lithium residual compounds during the solid–gas reaction. This work provides an effective method and insights into surface coating design to enhance electrochemical performance of Ni-rich cathode materials. [ABSTRACT FROM AUTHOR]

Abstract: A novel composite material Li2NaV2(PO4)3/C is developed by utilizing our latest finding to form less stable rhombohedral Li3V2(PO4)3 directly with partial substitution of Li+ to Na+ ions. In the prepared sample, rhombohedral Li3V2(PO4)3 becomes the dominant phase with a proportion of ∼59%, coexistent with monoclinic Li3V2(PO4)3 (10%) and rhombohedral Na3V2(PO4)3 (31%). High-resolution transmission electron microscopy (HRTEM) reveals that different phases coexist in the same primary particles. This characteristic is different from other cathodes, in which the primary particles are single- or poly-crystals. The prepared composite delivers a discharge capacity of 119.1 mAh g−1, of which 93.6% is centralized around 3.7 V vs. Li/Li+, in good agreement with phase''s ratio calculated from refinement. The plateaus of monoclinic Li3V2(PO4)3, appeared at 3.6 and 4.1 V vs. Li/Li+, play an additional role of indicator to warn the end of charge and discharge. This kind of electrode materials are particular suitable to build large batteries to power electric vehicles and shape the grid. [Copyright &y& Elsevier]