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Solid‐state electrolytes (SSE) exhibit great promise in enhancing the safety of Li metal batteries by replacing flammable liquid electrolytes. However, the practical application of SSE is hampered mainly due to the poor electrode–electrolyte interface, low ion conductivity, and inferior electrochemical stability. Herein, superior nonflammable solid polymer electrolytes are elaborately designed by in situ encapsulating succinonitrile (SN)‐based deep eutectic solvent (DES) into the ethoxylated trimethylolpropane triacrylate (ETPTA) matrix (DES‐ETPTA). Benefiting from strong polarity and high anti‐oxidation capability, as‐prepared DES‐ETPTA electrolyte shows high ionic conductivity (9.55 × 10−4 S cm−1 at 30 °C), high Li+ transference number (0.68), and good electrochemical stability. As a result, the assembled LiFePO4 || Li full cells based on the designed DES‐ETPTA electrolyte deliver a high reversible capacity and capacity retention at −10 °C and room temperature. Furthermore, considering the compatibility with high‐voltage layered oxide cathode, the electrochemical stability of the ETPTA is further improved through the decoration of cyanoacrylate (CA) with strong electron‐withdrawing characteristic of C≡N. Consequently, the constructed 4.5 V LiCoO2 || Li full cells using DES‐ETPTA‐CA electrolyte deliver a high reversible capacity of 144 mAh g−1 and a superior retention rate of 93% after 200 cycles at 0.5 C. This work paves a new pathway to design high‐safety and high‐voltage solid polymer electrolytes for lithium metal batteries. [ABSTRACT FROM AUTHOR]

Li‐rich Mn‐based layered oxides (LRLO) are considered promising cathode candidates for high‐energy‐density lithium‐ion batteries (LIBs). However, severe capacity/voltage fading and poor rate performance hinder their practical application. Herein, a microstructure engineering strategy is put forward to design the unique bayberry‐like Li1.2Mn0.54Co0.13Ni0.13O2 (LRLO‐S) cathode material, composed of a spherical core and the shell self‐assembled by radially oriented nanorods with intrinsic rapid electron and ion transport capability, benefiting to increase the electrochemical reaction kinetics during cycling. Meanwhile, the radial texturing of the nanorods in shell layer forms a natural protective interface constituted by thermodynamically stable (003) planes, resisting electrolyte corrosion effectively. Furthermore, the configuration of orderly self‐assembled nanorods can effectively regulate the stress and strain to stabilize the lattice framework, finally improves the cycling stability of LRLO. As a result, the elaborately designed LRLO‐S cathode delivers remarkable high‐rate long‐term cycling stability with high capacity retentions of 91.2% after 500 cycles at 1 C and of 81.3% after 1000 cycles at 5 C. More importantly, the voltage stability is enhanced greatly with a superior retention of 89.6% after cycling 500 times at 1 C. Here a valuable strategy is provided to develop intrinsic mechanically robust high‐performance Li‐rich‐layered cathode materials for advanced LIBs. [ABSTRACT FROM AUTHOR]

Lithium cobalt oxide (LCO) is the most widely used cathode materials in electronic devices due to the high working potential and dense tap density, but the performance is limited by the unstable interfaces at high potential. Herein, LiF thin film is sputtered on the surface of LCO electrodes for enhancing the electrochemical performance and reducing the voltage polarization. The polarization components are discussed and quantified by analyzing the relationship between electrochemical polarization and charger transfer resistance, as well as that between concentration polarization and Li-ion diffusion coefficients. In addition, the decreased charge transfer resistance, increased lithium-ion diffusion coefficients, and stabilized crystal structure of LiF-coated LCO are confirmed by various electrochemical tests and in-situ XRD experiments. Compared to that of pristine LCO, the capacity and cycling performance of LiF-coated LCO is improved, and the overpotential is reduced upon cycling. This work provides reference for quantifying the various polarization components, and the strategy of coating LiF film could be applied in developing other analogous cathode materials. [ABSTRACT FROM AUTHOR]

The voltage fade of Li-rich layered oxide cathode material Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2 (LNCM) heavily hinders its application in Li-ion batteries. Herein, we revisit the origin of the voltage fade of LNCM and propose a solution to suppress this effect. It is demonstrated that the voltage fade of the LNCM cathode comes from the structural change of the crystal from layer structure to spinel structure, involving all the cations rearrangement. Such rearrangement of all the cations in LNCM is due to the high degree of delithiation and oxygen release at high cutoff voltage of 4.8 V. It is also evidenced that nickel and cobalt change from low valence to high valence at the discharged state, which not only inhibits the transport of lithium ions, but also leads to the loss of high voltage platforms. In particular, the cation rearrangement of Li/Mn causes valence change from Mn4+ to Mn3+, resulting in the decrease of discharge voltage platform at the cutoff voltage of 4.8 V much higher than at 4.6 V. The lower charge cutoff voltage can be a solution to suppress the voltage fade of LNCM cathode materials and have a good stability of LNCM cathode materials without compromising the battery performance. Image 1 • The voltage fade of Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2 comes from the layer to spinel structure. • All the cations rearrangement involves in the structure change. • Nickel and cobalt change from low valence to high valence at the discharged state. • The Mn4+ to Mn3+ in Mn rearrangement decreases the discharge voltage platform. • The lower charge cutoff voltage is a solution to suppress the voltage fade of Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2 without compromising the battery performance. [ABSTRACT FROM AUTHOR]

Abstract The phase transition of Li-rich cathode materials occurred from surface to internal bulk structure leads to a poor stability of cycling performance, which seriously limits the development of the materials. Herein, with a facile designed hydrothermal method, the Li-rich layered oxides microspheres with the internal spinel phase are synthesized successfully. Compared with traditional hydrothermal method, a new heterostructured material exhibits high specific capacity remarkable cycling performance (247 mA h g−1 at 0.5 C) with high energy density (852 Wh kg−1). Under galvanostatic charge-discharge pattern, the discharge capacity retains about 91.5% after 300 cycles at a large current of 2 C. The full cell fabrication with artificial graphite as an anode and the synthesized heterostructured Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 O 2 material as cathode exhibits the favorable property and the practical applicability. We expect that this strategy is going to pave new ways to accelerate the property and application of Li-rich cathode oxides materials. [ABSTRACT FROM AUTHOR]

• A LiZn alloy/LiI hybrid protective layer in introduced on the surface of Li metal anode. • The hybrid protective layer reduces the nucleation barrier and facilitates Li+ diffusion. • The hybrid protective layer improves the electrochemical properties of Li metal anode. Lithium metal batteries (LMBs) are considered by most researchers as among the most prospective next-generation high energy density storage devices because of high theoretical capacity (3860 mAh g −1) and low reduction potential (–3.040 V compared to standard hydrogen electrode) of Li metal anode. Nevertheless, the uncontrollable dendrite growth of the Li metal anode during cycling hinders the commercial application of LMBs. Herein, we put forward a hybrid protective layer containing LiZn alloy and LiI at the surface of the Li metal anode. Thanks to the "lithiophilic" feature of LiZn alloy and LiI having a low surface Li+ diffusion energy barrier, the constructed homogeneous hybrid protective layer can reduce the nucleation barrier and facilitate Li+ rapid diffusion. As a consequence, Li metal anode exhibits a smooth plating/stripping morphology and can suppress the dendrite formation. Notably, the constructed ZI@Li || ZI@Li symmetrical cell realizes stable cycling for 470 h at 2 mA cm−2 and 2 mAh cm−2, and LMBs matched with commercial LiFePO 4 cathode deliver greatly enhanced electrochemical properties. This hybrid protective layer provides a feasible strategy to realize even plating/stripping of Li metal, which would promote the high energy density LMBs for practical applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The instability of lattice oxygen and the resulting chain reactions mainly originate at the interface between the electrolyte and the outmost surface of Li-rich Mn-based cathode materials (LRM). Although many research works are focused on improving the cycling performances of LRM by surface protection, the issue of voltage fading is still severing. To overcome the challenge, the MgNiO 2 surface heterointerface layer is constructed on the surface of cobalt-free LRM to form a heterointerface in this work, which can suppress side reactions at the interface, inhibit the dissolution of Mn elements, enhance the lattice oxygen stability, and stabilize the crystal structure. Benefiting from the above merits, the voltage fading value of the modified sample has been decreased by 28.2%. And the specific capacity retention of the modified sample (92.9%) is significantly higher than that of the pristine sample (80.9%). This work provides a valuable idea for optimizing the surface to improve the electrochemical performance of high-specific capacity Li-rich cathode materials. A MgNiO 2 surface heterointerface layer was constructed at the surface of cobalt-free Li-rich Mn-based cathode materials (MNO-LRM). The introduced MgNiO 2 layer can reduce the interface side reaction, mitigate the Mn dissolution, and stabilize the crystal structure. As a result, the designed MNO-LRM exhibits excellent voltage and cycling stability. [Display omitted] • A MgNiO 2 surface heterointerface layer is constructed in the Li-rich cathode. • The surface heterointerface layer enhances the interfacial and structural stability. • The MgNiO 2 -modified cathode exhibits enhanced electrochemical properties. [ABSTRACT FROM AUTHOR]

The instability of the anionic redox reaction and the resulting irreversible oxygen release are the core causes of the deterioration of the cycling stability of Li-rich cathode materials (LRM). The effective method is to establish a surface coating on the LRM, which is equivalent to converting surface oxygen on the LRM into bulk oxygen. However, developing a coating that can form a solid binding with the surface oxygen of the LRM remains challenging. To solve the above challenge, a uniform surface boron cobalt complexes (BCCs) coating was constructed on cobalt-free LRM. The constructed BCCs coating can significantly mitigate the interface side reaction, Mn dissolution, and irreversible gas release, and enhance structural stability. The cycling stability shows that the modified LRM cathode exhibits superior capacity retention (92.7 %) compared to that of the pristine LRM cathode (78.1 %) after 300 cycles at 1 C. This modification strategy heralds a useful paradigm for optimizing the cycling stability of LRM to promote their commercial application. [Display omitted] • A uniform boron cobalt complexes coating layer was introduced on the surface of cobalt-free Li-rich cathode material. • The coating layer can inhibit the interface side reaction and Mn dissolution, and improve the structural stability. • The modified cathode displays enhanced rate performance and cycling stability. [ABSTRACT FROM AUTHOR]

Co 2 P/graphene nanocomposites with graphene nanosheets anchoring with Co 2 P nanorods are prepared by a facile solution method. Their property as anode materials for lithium ion batteries is tested and compared with that of Co 2 P nanorods without anchoring on graphene. Compared to Co 2 P counterpart, Co 2 P/graphene nanocomposites exhibit more enhanced performance in Li-ion reversible capacity and cycleability. It is interesting that in both galvanostatic and rate cyclic performance, capacities show evidently increasing trend with increasing the cycle number, and then keep at an ultimate level around 800–900 mA h g −1 which is much higher than the theoretical capacity of Co 2 P and graphene. This enhanced property may concern with the abundant microspores in Co 2 P/graphene nanocomposites and the catalytic decomposition of solid electrolyte interphase (SEI). The effective combination of Co 2 P nanorods with graphene not only reduces the particle aggregation but also complement the limitations of Co 2 P as anode materials for lithium ion batteries. [ABSTRACT FROM AUTHOR]

Amorphous ZnSnO 3 -C hollow microcubes have been produced by calcination of the pre-synthesized ZnSn(OH) 6 hollow microcubes in argon, followed by the surface decoration of carbon. The calcination temperature plays an important role in the phase and morphology of the obtained products. ZnSnO 3 -C hollow microcubes have an average edge length of about 1.0 μm with the shell thickness of approximate 145 nm. When adopted as the anode materials for lithium ion batteries, amorphous ZnSnO 3 -C hollow microcubes manifest greatly enhanced electrochemical properties compared to amorphous ZnSnO 3 hollow and solid counterparts. After 50th cycles, a high reversible capacity of 703 mA h g −1 can be obtained for amorphous ZnSnO 3 -C hollow microcubes at the current density of 100 mA g −1 . The superior lithium storage properties of ZnSnO 3 -C are due to its unique hollow structure with large specific surface area, the modification of carbon and the amorphous characteristic. [ABSTRACT FROM AUTHOR]

Highlights: [•] ZnO-C yolk-shell microspheres, hollow microspheres and solid microspheres are prepared. [•] Yolk-shell ZnO-C microspheres possess the best electrochemical properties when used as the anode materials for lithium-ion batteries. [•] The special yolk-shell structures and extra carbon support account for the enhanced electrochemical properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Si layer is sputtered on the surface of Ti fibers by magnetron sputtering. • The STM electrodes exhibit good lithiophilicity and ion/electron conductivity. • Dendrite-free and smooth Li deposition is obtained on STM electrodes. • The STM@Li anodes deliver stable cycling in both symmetric and full cells. Li metal anode holds the key for further high-energy-density batteries. Inhibition of Li dendrites and superior electrochemical performance are critical for its practical application. Herein, a low-cost Si membrane with dual effects on 3D Ti mesh (STM) is designed through magnetron sputtering. The in situ formed Li-Si alloy layer presents highly lithiophilic and ion conductive, endowing lower nucleation barrier and homogeneous Li-ion flux, while the high electron conductive of 3D host with capacious voids immensely facilitates kinetics and relieves volume expansion. Consequently, a smooth Li layer looked like a "quilt" is uniformly formed instead of generating fair share of 1D Li whiskers. The constructed Li ‖ STM@Li symmetric cell keeps operating for 800 h at 2 mA cm−2 and 2 mAh cm−2 with a low overpotential of 25 mV. Even under carbonate-based electrolyte, the full cells using Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2 (LNCM) as cathode can deliver a high initial capacity (245 mAh g−1) and capacity retention (81.2%) after 100 cycles at 1 C. [ABSTRACT FROM AUTHOR]