Effects of Al2O3 and LiAlO2 Co-coating on electrochemical properties of LiNi0.8Co0.1Mn0.1O2 cathode materials

Lithium-ion batteries are widely used in aerospace, power vehicles, portable electronic devices and other fields because of their environmental friendliness, rechargeable cycle and high energy density. The nickel-cobalt-manganese ternary materials with high nickel has high specific discharge capacity and is regarded as one of the most promising cathode materials. However, with the increase of the number of cycles, the cycle performance becomes worse and the specific capacity decays sharply. In this work, Al₂O₃ and LiAlO₂ were coated on the surface of NCM811 by combining ball milling mixing and solid-phase synthesis to prepare the AL-NCM811 cathode material. The coating thickness formed by Al₂O₃ and LiAlO₂ was 10–70 nm, which effectively improves the cycle stability and rate performance of NCM811 material. When charged and discharged at 0.1C, the first discharge specific capacity and capacity retention rate after 100 cycles of 0.5AL-NCM811 were 196.26 mAh/g and 96.47%, respectively, while those of NCM811 were only 193.78 mAh/g and 72.18%, respectively. When the current density was 5.0C, the discharge specific capacity of 0.5AL-NCM811(139.16 mAh/g) was 55.368 mAh/g higher than that of NCM811(83.80 mAh/g).     

Mitigating storage-induced degradation of Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode material by surface tuning with phosphate

The Ni-rich LiNi_0.8Co_0.1Mn_0.1O₂ layered oxide (NCM811) is attracting considerable attention as a high-capacity cathode material for rechargeable Li-ion batteries. However, due to its inherent structural/chemical/electrochemical instability, NCM811 with high Ni content suffers from significant performance degradation upon storage even in ambient atmospheres as well as during charge–discharge cycling. Herein, we demonstrate a simple but effective surface-tuning approach to mitigate storage-induced degradation of NCM811, which is based on the conversion of undesirable Li residues to a protective Li₃PO₄ nanolayer via phosphate treatment. The accelerated storage stability test shows that phosphate-modified NCM811 exhibits remarkably improved electrochemical performance (capacity, cycle life, and rate capability) over the pristine one after being stored under harsh environmental conditions. A combined analytical study indicates that surface tuning through phosphate treatment enhances the storage stability of NCM811 by eliminating impurity-forming Li residues and producing a Li₃PO₄ nanolayer that inhibits parasitic reactions at the electrode–electrolyte interface. Furthermore, Li₃PO₄ provides an effective barrier to H₂O and CO₂ infiltration into the particle agglomerates, thereby suppressing the loss of particle integrity.     

Influence of lithium difluorophosphate additive on the high voltage LiNi0.8Co0.1Mn0.1O2/graphite battery

Lithium-ion batteries (LIBs) possessing high energy densities are driven by the growing demands of electric vehicles (EVs) and hybrid electric vehicles (HEVs). One of the most effective strategies to improve the energy density of LIBs is to enlarge the charge cut-off voltage via a lithium salt additive for the conventional electrolyte system. Herein, lithium difluorophosphate (LIDFP) is employed to optimize and reconstruct the composition of the structure and interface for both cathode and anode, which can effectively restrain the oxidation decomposition of electrolyte as well as refrain the dissolve out of transition metals. The LiNi_0.8Co_0.1Mn_0.1O₂ (LNCM811)/graphite pouch cell with 1 wt% LIDFP in electrolyte delivers a discharge capacity retention of 91.3% at a high voltage of 4.4 V over 100 cycles, which is higher than the 82.0% of that without LIDFP additive. Additionally, the remaining capacity of LNCM811/C battery with 1 wt% LIDFP additive which is left at 60 °C for 14 days is 85.2%, and the recovery capacity is 93.3%. The LIDFP-containing electrolyte demonstrates a great application future for the LiBs operating under the high-voltage condition and high-temperature storage performance.     

Al-Doped Li[Ni0.78Co0.1Mn0.1Al0.02]O2 for High Performance of Lithium Ion Batteries

Li[NixCoyMnz]O₂ (NCM) layered materials have been successfully adopted in commercial lithium ion batteries (LIBs). The presence of higher Ni content in cathode materials helps to improve the capacity. However, increased cation mixing on the surface of layered material leads to unstable structure. Aluminium (Al) doping is known to enhance the performance of cathode material by rendering thermal and structural stability. In this article, we synthesize Li[Ni_0.8Co_0.1Mn_0.1]O₂ (Bare NCM811) and Li[Ni_0.78Co_0.1Mn_0.1Al_0.02]O₂ (Al-Doped NCM811) using simple co-precipitation process followed by calcination process. The electrochemical, morphological, and structural characteristics of the Al-Doped NCM811 are investigated and compared with the Bare NCM811. The discharge capacity of the Bare NCM811 and the Al-Doped NCM811 maintained 73.59% and 96.15% after the 100th cycle at a room temperature of 20?°C and 87.32% and 94.38% after the 50th cycle at an elevated temperature of 60?°C, respectively. The enhanced electrochemical performance of Al-Doped NCM811 is attributed to the improved thermal and structural properties of the electrode, as confirmed using differential scanning calorimeter (DSC) and particle compression tester (PCT).     

Dual functions of three-dimensional hierarchical architecture on improving the rate capability and cycle performance of LiNi0.8Co0.1Mn0.1O2 cathode material for lithium-ion battery

The main obstacles in lithium-ion battery are limited by rate performance and the rapid capacity fading of LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811). Herein, a novel three-dimensional (3D) hierarchical coating material has been fabricated by in situ growing carbon nanotubes (CNTs) on the surfaces of Ni–Al double oxide (Ni–Al-LDO) sheets (named as LDO&CNT) with Ni–Al double hydroxide (Ni–Al-LDH) as both the substrate and catalyst precursor. The resultant LDO&CNT nanocomposites are uniformly coated on the surfaces of NCM811 by the physical mixing method. The rate capability of the resultant cathode material retains to 78.80% at a current rate of 3C. Its capacity retention increases by 6.7–14.42% compared with pristine NCM811 after 100 cycles within a potential range of 2.75–4.3 V at 0.5C. The improved rate capability and cycle performance of NCM811 are assigned to the synergistic effects between Ni–Al-LDO and CNTs. The hierarchical LDO&CNT nanocomposites coating on the surface of NCM811 avoids the aggregation of conductive CNTs and the stacking of Ni–Al-LDO nanosheets. Furthermore, it accelerates Li⁺ and electrons shuttle and reduces the reaction of Li₂O with H₂O and CO₂ in air, which results in Li₂CO₃ and LiOH alkali formation on the NCM811 surface.     

Enhancing high-potential stability of Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode with PrF3 coating

It is still a huge challenge to improve the safety and stability of Ni-rich (LiNi_0.8Co_0.1Mn_0.1O₂) cathode materials at elevated potential. Herein, the PrF₃ layer is employed to protect LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) via a simple wet chemical process. It was confirmed by XRD, HR-SEM, TEM, EDS, and XPS tests that PrF₃ is evenly covered throughout the surface of NCM811 without affecting the particle size and surface morphology. In particular, 1 wt% PrF₃ coated NCM811 exhibits excellent stability and rate capability with the capacity retention of 86.3% after 100 cycles at 1 C under a cut-off potential of 4.3 V, while the retention of pristine one is only 73.8%. Moreover, the capacity retention of 1 wt% PrF₃ coated samples enhances from 74.5% to 88.5% after 50 cycles at 1 C under higher cut-off voltage of 4.6 V. The superior performance for coated samples can be attributed to the fact that PrF₃ can effectively isolate the active material and the electrolyte from HF corrosion, and at the same time, reduce the generation of micro-cracks on the surface during prolonged cycles. Furthermore, as a physical barrier, PrF₃ alleviates the dissolution of transition metals in the electrolyte largely. These results suggest that the stability of NCM811 can be greatly upgraded at high voltage by PrF₃ coating.     

Recent progress in coatings and methods of Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode materials: A short review

LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) is a typical nickel (Ni)-rich ternary cathode material with several advantages, such as high specific capacity, low-cost, and environmentally friendly, making it a good candidate for use in lithium-ion batteries. However, its Ni content is as high as 80%; therefore, several new problems have emerged with gradually increasing applications. In this review, Li–Ni disorder and corresponding modification methods are first briefly reviewed, and then the origin of complex surface defect, which has a crippling effect on diffusion processes of Li⁺ at electrolyte/cathode interface, is discussed in detail. Analyses showed the importance of selecting appropriate surface modification material/technique for enhancing electrochemical properties. Therefore, popular surface coating materials and methods including metal oxides, fluorides, phosphates, fast ion conductors, and other compounds/elements used for the development of NCM811 are subjected to extensive and thorough research. Finally, several new perspectives and insights related to stability and safety at high voltages and temperatures, and the optimization of production process are also proposed.     

Surface modification of Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode materials via a novel mechanofusion alloy route

This study aimed to prepare a composite coating material comprising a solid ionic conductor of lithium aluminum titanium phosphate (Li_1.4Al_0.4Ti_1.6(PO₄)₃, LATP) and porous carbon through a sol-gel method. LiNi_0.8Co_0.1Mn_0.1O₂ (LNCM811) cathode material with dual-functional composite conductors (i.e., LATP@porous carbon), denoted as LATP-PC, was prepared. The dry-coating method, also called the “mechanical-fusion alloy route,” was used to modify Ni-rich LNCM811 cathode materials. X-ray diffraction (XRD), micro-Raman spectroscopy, and X-ray photoelectron spectroscopy confirmed that the LATP ionic conductor generated herein was uniformly deposited on 3D porous carbon and served as a dual-functional composite coating on LNCM811. Furthermore, the capacity retention of LATP-PC@LNCM811 was approximately 85.57% and 80.86% after 100 cycles at −20 °C and 25 °C, respectively. By contrast, pristine LNCM811 had the capacity retention of 78% and 74.96% at −20 °C and 25 °C, respectively. Furthermore, the high-rate capability of the LATP-PC@LNCM811 material was markedly enhanced to 169.81 mAh g⁻¹ at 10C relative to that of pristine LNCM811, which was approximately 137.67 mAh g⁻¹. The electrochemical performance of LNCM811 was enhanced by the uniform dual-conductive composite coating. The results of the study indicate that the LATP-PC@LNCM811 composite material developed herein is a potentially promising material for future high-energy Li-ion batteries.     

Effect of excess Li2S on electrochemical properties of amorphous li3ps4 films synthesized by pulsed laser deposition

Amorphous Li₃PS₄ films were synthesized by pulsed laser deposition (PLD) at room temperature using Li₃PS₄ targets with excess lithium and sulfur. Raman and X‐ray photoemission spectroscopies indicated that the Li₃PS₄ film synthesized with a stoichiometric amount of Li₃PS₄ target contained lithium‐deficient phases such as Li₄P₂S₆, Li_2?xS and sulfur due to composition deviation caused during the ablation process. The film synthesized with a 14% Li₂S‐excess target (Li_3.42PS_4.21) contained fewer impurities, and exhibited a higher ionic conductivity of 5.3 × 10^?4 S/cm at 298 K than the lithium‐deficient film (3.1 × 10^?4 S/cm). The target composition is an important factor for the fabrication of highly conductive Li₃PS₄ films for electrolytes in thin‐film batteries.     

Effect of cell pressure on the electrochemical performance of all-solid-state lithium batteries with zero-excess Li metal anode

All-solid-state cells (ASSCs) typically operate at a specific pressure to ensure good contact between the solid electrolyte and the electrode-active materials. However, establishing the ideal cell pressure is challenging because of the various cell structures, the mechanical characteristics of solid electrolytes, and the extent to which the volume of the electrodes changes during cycling. In this study, we propose a specially designed cell assembly that adjusts to the changes in volume that occur during cycling while maintaining a constant cell pressure. The evaluations indicate that the spring in the cell assembly effectively reduces the stress incurred from the volume expansion that occurs in the electrode during charging (lithiation) and the volume contraction that occurs during discharging (delithiation) while maintaining the prescribed cell pressure. The capacity fading—as a function of the cycle number—decreases when operating ASSCs comprising a cell assembly that include a spring, compared with those that exclude a spring. Focused ion beam–scanning electron microscope reveals no cracks and delamination in the LiNi_0.8Co_0.1Mn_0.1O₃ (NCM811) composite cathode of the ASSCs, operated at 25 MPa, with a spring-equipped assembly. The Ag nanolayer that deposits on the Cu foil is an effective collector metal, forming a dense lithium plating layer on the Ag/Cu foil anode.     

Designable air-stable and dendrite-free Li metal anode via the oligomer layer for in-situ gel polymer batteries

Lithium (Li) metal anode has been an indispensable electrode material in the development of the future battery system, especially in the pursuit of energy density of the solid state battery. However, the poor air stability and dendrite problems are stumbling blocks to the practical application of Li metal anode. Herein, we design the poly(methyl methacrylate) (PMMA) oligomer coating layer for the surface of Li metal anode (Li-PMMA). The Li-PMMA anode can obtain hydrophobic oxygen resistance ability and maintain air stability for 48h in the environment of 70% relative humidity. When applied to the liquid battery, the PMMA oligomer can open the double bond by the catalysis of Li⁺ and repolymerize into the PMMA gel polymer electrolyte (GPE). As a result, the cathode and anode are cohered together by GPE to become an in-situ GPE battery. The GPE displays high ionic conductivity (7.92 mS cm^-1) and perfect interfacial contact with various electrodes. The newly designed in-situ GPE is employed to Li||Li symmetric battery without separator, which can run up to 2000 h with the overpotential of only 2.8 mV. Applications of the in-situ GPE in Li-S battery and 5000mAh LiNi_0.5Co_0.2Mn_0.3O₂/Li pouch cell both obtain excellent electrochemical performance. Our strategy may provide a versatile and practical approach to promote the large-scale application for solid state Li metal batteries.     

Particle size control of cathode components for high-performance all-solid-state lithium–sulfur batteries

Understanding the size effect of each component on battery performance is essential for designing high-performance Li₂S/S cathode for all-solid-state Li–S batteries. However, the size effects of different components are always coupled because ball-milling, an indispensable process to synthesize reversible cathode, simultaneously and uncontrollably reduces the particle size of all the components. Here, a liquid-phase method, without ball-milling, is developed to synthesize the Li₂S composite cathode, so that the particle size of the active material Li₂S and the solid electrolyte Li₃PS₄ (LPS) can be independently controlled at nano- or microscale. This helps reveal that compositing Li₂S and the conductive agent at nanoscale is essential for enhancing the reaction kinetics, whereas the nanoscale particle size and homogenous distribution of LPS is important for accommodating the large volume change of the cathode. By reducing the particle size of Li₂S to 9.4 nm and that of LPS to 44 nm, the liquid-phase-synthesized composite cathode exhibits reversible capacity and 100% utilization of Li₂S under 0.1 C rate.     

In situ transmission FTIR spectroelectrochemistry: A new technique for studying lithium batteries

In situ transmission FTIR spectra are measured during the electrochemical insertion of lithium into phospho-olivine FePO₄. The spectroelectrochemical cell consists of a composite FePO₄ cathode, a lithium metal anode, and an electrolyte of 1 M LiPF₆ in a 1:1 mixture of ethylene carbonate and diethyl carbonate (EC-DEC). Bands belonging to the electrolyte and cathode are identified in the infrared spectra of the in situ cells. The antisymmetric PO₄³⁻ bending vibrations (ν₄) are used to monitor Li⁺ insertion into FePO₄. Discharging produces spectral changes that are consistent with the formation of phospho-olivine LiFePO₄, yet the electrolyte bands are not affected by the discharging process. The in situ infrared experiments confirm the two-phase mechanism for lithium insertion into FePO₄. Moreover, the experiments demonstrate the ability to collect in situ transmission FTIR spectra of functioning electrode materials in lithium batteries. Unfortunately, lithium plating occurs on the optical window when the Li//FePO₄ half-cells are charged. The use of an intercalation anode such as graphite could alleviate this problem; however, this avenue of research is not explored in this study.     

Review of Computational Studies of NCM Cathode Materials for Li-ion Batteries

Lithium-ion based rechargeable batteries are considered among the most promising battery technologies because of the high energy- and power-densities of these electrochemical devices. Computational studies on lithium ion batteries (LIBs) facilitate rationalization and prediction of many important experimentally observed properties, including atomic structure, thermal stability, electronic structure, ion diffusion pathways, equilibrium cell voltage, electrochemical activity, and surface behavior of electrode materials. In recent years, Ni, Co and Mn-based (NCM) layered transition metal oxide positive electrode materials (LiNi_1-x-yCo_xMn_yO₂) have shown tremendous promise for high-energy density LIBs, and these NCM-based batteries are effectively commercialized. Here, we present an overview of recent theoretical work performed using first principles density functional theory on these layered cathode materials. This short review focuses on recent computational efforts of popular NCMs with increasing Ni content, ranging from NCM333 to NCM811.     

Boosting lithium-ion transport capability of LAGP/PPO composite solid electrolyte via component regulation from ‘Ceramics-in-Polymer’ to ‘Polymer-in-Ceramics'

The design and regulation of the ion transport channels in the polymer electrolyte is an important means to improve the lithium ion transport behavior of the electrolyte. In this work, we for the first time combined the high ionic conductive inorganic ceramic electrolyte Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP) with flexible polypropylene oxide (PPO) polymer electrolyte to synthesize a high-filling LAGP/PPO composite solid electrolyte film and regulated the ion transport channels from ‘Ceramics-in-Polymer’ mode to ‘Polymer-in-Ceramics' mode by optimizing the ratio of LAGP vs. PPO. The results reveal that when the LAGP content <40%, the electrolyte belongs to ‘LAGP-in-PPO’, and then changes to ‘PPO-in-LAGP’ when the LAGP content exceeds 40%. Compared with ‘LAGP-in-PPO’, the ‘PPO-in-LAGP’ shows better comprehensive properties, especially for the 75% LAGP-filled PPO electrolyte, the room-temperature ionic conductivity is as high as 3.46 × 10^?4 Scm^?1, the ion migration number and voltage stable window reach 0.83 and 4.78 V respectively. This high-filled composite electrolyte possesses high tensile stress of 40 MPa with a strain of 46% and withstands working environment up to 200 °C. The NCM622/Li solid-state battery composed of this electrolyte also presents good rate and cycle performances with a capacity retention of 80% after 230 cycles at 0.3C because of its high ion transport capability and good inhibition of lithium dendrites. This composite structural design is expected to develop high-performance solid-state electrolytes suitable for high-voltage solid-state lithium batteries.     

Rapid preparation and performances of garnet electrolyte with sintering aids for solid-state Li–S battery

Lithium-sulfur (Li–S) batteries are attractive due to their high theoretical energy density. However, conventional Li–S batteries with liquid electrolytes undergo polysulfide shuttle-effect and lithium dendrite formation during charge/discharge process, leading to poor electrochemical performance and safety issues. Garnet type Li₇La₃Zr₂O₁₂ (LLZO) solid-state electrolyte (SSE) restricts the penetration of polysulfides and exhibits high ionic conductivity at room temperature (RT). Herein, Li_6.5La₃Zr_1.5Nb_0.5O₁₂ (LLZNO) ceramic electrolyte using Li₃PO₄ (LPO) as sintering aids (LLZNO-LPO) is prepared by the rapid sintering method and is applied to construct a shuttle-effect free solid-state Li–S battery. The SSE displays high conductive pure cubic-LLZO phase; during the rapid sintering, LPO melts and junctions the voids between the grains, thus improves Li⁺ conductivity. As a result, the LLZNO-LPO ceramic electrolyte with Li⁺ conductivity of 4.3 × 10^?4 S cm^?1 and high critical current density (CCD) of 1.2 mA cm^?2 is obtained at RT. The Li–S solid-state battery which utilizes LLZNO-LPO ceramic electrolyte can deliver an initial discharge capacity of 943 mA h·g^?1 and 602 mA h·g^?1 retention after 60 cycles. In the same time, the initial coulombic efficiency is as high as 99.5%, indicating that the SSE can effectively block the polysulfide shuttle towards the Li anode and fulfill a shuttle-free Li–S battery.     

Controllable Li3PS4–Li4SnS4 solid electrolytes with affordable conductor and high conductivity for solid-state battery

High ionic conductivity, low grain boundary impedance, and stable electrochemical property have become the focus for all-solid-state lithium–sulfur batteries (ASSLSB). One of the approaches is to promote the rapid diffusion of lithium ions by regulating the chemical bond interactions within the framework. The structure control of P⁵⁺ substitution for Sn⁴⁺ on lithium-ion transport was explored for a series of Li₃PS₄–Li₄SnS₄ glass–ceramic electrolytes. Results showed that the grain boundary impedance of the glass electrolyte was reduced after heat treatments. The formation of LiSnPS microcrystals, a good superionic conductor, was detected by X-ray diffraction tests. Electrochemical experiments obtained the highest conductivity of 29.5 S cm⁻¹ at 100°C and stable electrochemical window from –0.1 to 5 V at 25°C. In addition, the cell battery was assembled with prepared electrolyte, which is promoted as a candidate solid electrolyte material with improved performance for ASSLSB.     

MnO2 cathode in an aqueous Li2SO4 solution for battery applications

A manganese dioxide (MnO₂) cathode with zinc (Zn) as the anode has been investigated using lithium sulphate (Li₂SO₄) as an electrolyte. Previously we demonstrated that cells comprising MnO₂ and lithium hydroxide (LiOH) as an electrolyte can be made rechargeable to over one-electron capacity with a discharge capacity of 150 mAh g⁻¹. Here we have extended our work to assess Li₂SO₄ as an electrolyte and have found that the battery is not rechargeable. Based on the electrochemical (discharge/charge) performance and the products formed following discharge and charge, the mechanism proposed for the sulphate-based media is one of proton insertion into the MnO₂ cathode, rather than the lithium ion insertion observed for the LiOH electrolyte. The addition of bismuth species to the Li₂SO₄-based cell results in a transition to rechargeable behaviour. This is believed to be due to the influence of Bi ions on the formation of soluble Mn³⁺ soluble intermediates. However, the coulombic efficiency of the cell diminishes rapidly with repeated charge/discharge cycles. This confirms that the nature of the Li-containing electrolyte has a marked influence on the electrochemistry of the cell.     

A systematic study on structure,ionic conductivity,and air-stability of xLi4SnS4·(1−x)Li3PS4 solid electrolytes

In order to use sulfide all-solid-state batteries as power sources of electric devices, sulfide solid electrolytes with high ionic conductivity and high air-stability must be developed. Li₃PS₄ electrolytes have been used in all-solid-state batteries because of their relatively high ionic conductivity (4 × 10 ⁻⁴ S cm⁻¹ at 25 °C) and higher air-stability than those of other Li₂S–P₂S₅ type solid electrolytes. Herein, the Li₄SnS₄–Li₃PS₄ system was investigated to (1) increase the ionic conductivity of Li₃PS₄ using excess Li carriers and (2) improve the air-stability of Li₃PS₄ by introducing air-stable Sn–S bonds. The structure, ionic conductivity, and air-stability of xLi₄SnS₄·(1−x)Li₃PS₄ were systematically investigated; the results showed that adding small amounts of Li₄SnS₄ to Li₃PS₄ glass and glass-ceramic enhanced their ionic conductivity and air-stability without degrading their electrochemical stability. In particular, the 0.3Li₄SnS₄·0.7Li₃PS₄ glass-ceramic showed an ionic conductivity of 8.1 × 10 ⁻⁴ S cm⁻¹ at 25 °C and generated only a small amount of H₂S gas (3 ppm [0.3 cm³ g⁻¹]) when it was dissolved in water. Hence, xLi₄SnS₄·(1−x)Li₃PS₄ solid electrolytes can be used as alternatives to the conventional Li₃PS₄ electrolyte because of their various advantages and a simple preparation method that involves adding only SnS₂ to conventional starting materials.     

Surface modification of Li1.3Al0.3Ti1.7(PO4)3 ceramic electrolyte by Al2O3-doped ZnO coating to enable dendrites-free all-solid-state lithium-metal batteries

The Na⁺ super-ionic conductor (NASICON) type solid electrolytes Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) are of increasing interest because of their high total ionic conductivity and excellent stability against moist air. However, they are not stable when contacting with lithium metal because of the rapid Ti⁴⁺ reduction by Li metal, which greatly restrict their application in lithium batteries. Here, we propose a Al₂O₃-doped ZnO (AZO) surface coating method by magnetron sputtering to improve the stability of the Li_1.3Al_0.3Ti_1.7(PO₄)₃ electrolyte against the attack of lithium-metal anode and to avoid the growth of lithium dendrite. The Al₂O₃-doped ZnO coating of the electrolyte Li_1.3Al_0.3Ti_1.7(PO₄)₃ demonstrates high chemical stability against the attack of lithium-metal in a wide electrochemical potential ranges (>5 V), as well as an excellent performance of suppressing of lithium dendrites. Furthermore, the Al₂O₃-doped ZnO coated Li_1.3Al_0.3Ti_1.7(PO₄)₃ was found to be the candidate electrolyte for the all-solid-state lithium battery. An all-solid-state Li/LiFePO₄ battery with Al₂O₃-doped ZnO coated Li_1.3Al_0.3Ti_1.7(PO₄)₃ as the solid electrolyte shows good cyclability and a high columbic efficiency for 50 charge/discharge cycles. Furthermore, the surface-modified electrolyte Li_1.3Al_0.3Ti_1.7(PO₄)₃ by Al₂O₃-doped ZnO coating also enables the lithium metal battery to exhibit extremely long cycling for nearly 1000 h due to the ability of suppressing of lithium dendrites.