Reversible Capacity Research Articles

Dual-Carbon Phase-Encapsulated Prelithiated SiOx Microrod Anode for Lithium-Ion Batteries.

Among silicon-based anode family for Li-ion battery technology, SiOx, a nonstoichiometric silicon suboxide holds the potential for significant near-term commercial impact. In this context, this study mainly focuses on demonstrating an innovative SiOx@C anode design that adopts a pre-lithiation strategy based on in situ pyrolysis of Li-salt of silsesquioxane trisilanolate without the need for lithium metal or active lithium compounds and creates dual carbon encapsulation of SiOC nanodomains by simply one-step thermal treatment. This ingenious design ensures the pre-lithiation process and pre-lithiation material with high-environmental stability. Moreover, phenyl-rich organosiloxane clusters and polyacrylonitrile polymers are expected to serve as internal and external carbon source, respectively. The formation of an interpenetrating and continuous carbon matrix network would not only synergistically offer an improved electrochemical accessibility of active sites but also alleviate the volume expansion effect during cycling. As a result, this new type of anode delivered a high reversible capacity, remarkable cycle stability as well as excellent high-rate capability. In particular, the L2-SiOx@C material has a high initial coulomb efficiencof 80.4% and, after 500 cycles, a capacity retention as high as 97.5% at 0.5 A g-1 with a reversible specific capacity of 654.5mA h g-1.

Boosting potassium and sodium-ion storage performance by in-situ self-assembly of a Co-based π-d conjugated coordination polymer on graphene nanosheets

To obtain anode materials with good electrochemical performances in both potassium ion batteries (PIBs) and sodium-ion batteries (SIBs), a Co-based π-d conjugated coordination polymer (Co-HHTP) is in-situ assembled on graphene (G) nanosheets using a facile one-step solvothermal method. The resulting Co-HHTP/G composite shows improved electrochemical performances over pure Co-HHTP. After 300 cycles of using as an anode of PIBs/SIBs for the first time, the reversible specific capacity of the Co-HHTP/G composite is found to be 381/277 mAh g−1 at 100 mA g−1. After undergoing 500 cycles at 1000 mA g−1, the material's reversible specific capacities remain at 234/164 mAh g−1 for PIBs/SIBs. The improved performances of the Co-HHTP/G composite electrode are due to the incorporation of graphene. This incorporation not only reduces structural stacking and promotes active site utilization, but also increases electrical conductivity and structural stability. According to the ex-situ X-ray photoelectron spectrometer (XPS) spectra, the Co-HHTP/G's energy storage mechanism throughout the process of potassisation/depotassisation is found to be linked to the aromatic rings presented in the organic ligands.

In-situ ions Induced Formation of KxF-rich SEI Layers towards Ultra-Stable life of Potassium Ion Batteries.

Engineering F-rich SEI layers is regarded as an effective strategy to enable the long-term cycling stability of potassium ion batteries (KIBs). However, in the conventional KPF6 carbonate electrolytes, it is challenging to form F-containing SEI layers due to the inability of KPF6 to decompose into KxF. Herein, AlCl3 is employed as a novel additive to change the chemical environment of the KPF6 carbonate electrolyte. Firstly, due to the large charge-to-radius ratio of Al3+, the Al-containing groups in the electrolyte can easily capture F from PF6 - and accelerate the formation of KxF in SEI layer. In addition, AlCl3 also reacts with trace H2O or solvents in the electrolytes to form Al2O3, which can further act as an HF scavenger. The "self-induced formation" of F-rich SEI layers (KxF and AlF3) and "self-elimination" of unexpected species (H2O and HF) guarantee the excellent long-term cycling stability of KIBs. Upon incorporating AlCl3 into conventional KPF6 carbonate electrolyte, the hard carbon (HC) anode exhibits an ultra-long lifespan of 10000 cycles with a high coulombic efficiency of ∼100%. When coupled with PTCDA, the full cell exhibits a high capacity retention of 81% after 360 cycles-significantly outperforming cells using conventional electrolytes. Moreover, PTCDA||HC pouch cell using AlCl3 added KPF6 electrolyte deliver a reversible capacity of 93 mAh g-1 with capacity retention of 86% after 80 cycles. This research paves new avenues for advancing electrolyte engineering towards developing durable batteries tailored for large-scale energy storage applications. This article is protected by copyright. All rights reserved.

Rationally Regulating Closed Pore Structures by Pitch Coating to Boost Sodium Storage Performance of Hard Carbon in Low‐voltage Platforms

AbstractHard carbon (HC) materials with rich closed pore structures and nano‐scaled soft carbon coating layer have emerged as promising anode in sodium‐ion batteries (SIBs). However, it still remains a tremendous challenge to precisely regulate closed pore structures and soft carbon coating thicknesses for achieving excellent electrochemical performance in SIBs at low‐voltage platforms. Herein, PCHC‐10 with abundant and suitable‐sized closed pore size (0.45 nm) and nano‐scaled soft carbon coating layer has been accurately designed by chemical crosslink reaction between the pre‐oxidized phenolic resin and a small addition of pitch to form ester‐based bond. As anode, PCHC‐10 delivered large reversible capacity of 359.8 mAh g−1 within 0.001–2.5 V, and high capacity of 242.8 mAh g−1 in low voltage platforms (≤0.15 V). Besides, PCHC‐10 anode exhibits 91.4% capacity retention for 100 cycles, and Na3V2(PO4)3//PCHC‐10 full cell has superior rate performance and high energy density of 231.2 Wh kg−1. Furthermore, the detailed electrochemical storage behaviors and theoretical calculations revealed that the HC owning closed pore‐size of 0.45 nm has the strongest Na+ storage abilities in low‐voltage platforms. This work presents a novel insight for constructing HC with suitable‐sized closed pore structures and soft coating layer to boost Na+ storage capability in low‐voltage platforms.

Versatile separators toward advanced lithium-sulfur batteries: status, recent progress, challenges and perspective.

Lithium-sulfur batteries (LSBs) have recently gained extensive attention due to their high energy density, low cost, and environmental friendliness. However, serious shuttle effect and uncontrolled growth of lithium dendrites restrict them from further commercial applications. As "the third electrode", functional separators are of equal significance as both anodes and cathodes in LSBs. The challenges mentioned above are effectively addressed with rational design and optimization in separators, thereby enhancing their reversible capacities and cycle stability. The review discusses the status/operation mechanism of functional separators, then primarily focuses on recent research progress in versatile separators with purposeful modifications for LSBs, and summarizes the methods and characteristics of separator modification, including heterojunction engineering, single atoms, quantum dots, and defect engineering. From the perspective of the anodes, distinct methods to inhibit the growth of lithium dendrites by modifying the separator are discussed. Modifying the separators with flame retardant materials or choosing a solid electrolyte is expected to improve the safety of LSBs. Besides, in-situ techniques and theoretical simulation calculations are proposed to advance LSBs. Finally, future challenges and prospects of separator modifications for next-generation LSBs are highlighted. We believe that the review will be enormously essential to the practical development of advanced LSBs.

Heterostructure Engineering Enables MoSe2 with Superior Alkali-Ion Storage

Molybdenum diselenide (MoSe2) is a promising anode for alkali-ion storage due to its intrinsic advantages. However, MoSe2 still encounters the issues of structural instability and poor rate performance caused by drastic volume change and sluggish reaction kinetics. Reasonable design of electrode structure is crucial for achieving superior electrochemical performance. Herein, a novel hierarchical structure coupled with 1D/1D subunits is elaborately designed and constructed, in which the MoSe2/CoSe2 heterostructure is the “trunk” and the N-doped carbon nanotubes are the “branches” (MoSe2/CoSe2/NCNTs). Benefiting from the properties endowed by unique configurations, MoSe2/CoSe2/NCNTs electrodes manifest faster reaction kinetics and better structure durability. Evaluated as an anode for LIBs and SIBs, MoSe2/CoSe2/NCNTs deliver high reversible capacity, superior rate capability (452 at 10 A g−1 in LIBs and 296 at 10 A g−1 in SIBs), and prominent cycle life (553 after 2000 cycles at 5 A g−1 in LIBs and 310 after 2000 cycles at 5 A g−1 in SIBs). Such design conception can also provide guidance for the development of other high-performance electrodes.

Double-Salts Super Concentrated Carbonate Electrolyte Boosting Electrochemical Performance of Ni-Rich LiNi0.90Co0.05Mn0.05O2 Lithium Metal Batteries.

Current lithium-ion batteries cannot meet the requirement of higher energy density with further large-scale application of electrical vehicles. Lithium metal batteries combined with Ni-rich layered oxides cathode are expected as the one of promising solutions, while the poor electrode and electrolyte interface impedes the commercial development of lithium metal batteries. A new double-salts super concentrated (DSSC) carbonate electrolyte is proposed to improve the electrochemical performance of LiNi0.90Co0.05Mn0.05O2 (NCM9055)||Li metal battery which exhibits stable cycling performance with the capacity retention of 93.04% and reversible capacity of 173.8 mAh g-1 after 100 cycles at 1 C, while cells with conventional 1m diluted electrolyte remains only 60.55% and capacity of 114.2 mAh g-1. The double salts synergistic effect in super concentrated electrolyte promotes the formation for more balanced stable cathode electrolyte interface (CEI) inorganic compounds of CFx, LiNOx, SOF2, Li2SO4, and less LiF by X-ray photoelectron spectroscopy (XPS)test, and the uniform 2-3nm rock-salt phase protection layer on the cathode surface by transmission electron microscope (TEM) characterization, improving the cycling performance of the Ni-rich NCM9055 layered oxide cathode. The DSSC electrolyte also can relief the Li dendrite growth on Li metal anode, as well as exhibit better flame retardance, promoting the application of more safety Ni-rich NCM9055||Li metal batteries.

An intellectual property analysis: advances and commercialization of low-dimensional carbon materials in batteries

There is a growing demand for energy consumption in society due to the increasing application of emerging technologies. Therefore, the need for the development of advanced energy storage technologies to cope with the rising energy demand is rising. Carbon materials play significant roles in energy storage technologies. In this review, the research progress and applications of low-dimensional carbon materials in batteries, including carbon quantum dots, carbon nanotubes, and graphene, are summarized. The performance of these materials is compared against traditional lithium-ion batteries with graphite, which has limitations in its bandgap and reversible capacity. A mini-intellectual property analysis and the advances and commercialization of low-dimensional carbon materials in batteries were provided. The challenges and limitations associated with using these materials as electrode materials were discussed, and a market overview of their commercialization was provided. Finally, future directions for research and development in this field were concluded. Overall, this review provides a comprehensive overview of low-dimensional carbon materials as a promising research area for developing advanced batteries to meet the growing demand for energy consumption.

Engineering Porous Carbon with Precise Sizes to Promote Surface‐Dominated Storage in Sodium‐Ion Batteries

AbstractAs the sole commercially viable anode material for sodium‐ion batteries, hard carbon currently faces challenges such as slow diffusion kinetics in the low voltage range and low safety due to sodium deposition. In order to deepen the understanding of the pseudocapacitive processes of hard carbon in the high voltage range and enhance sodium storage capacity, this study systematically investigates the electrochemical performance and ion storage of ZIF‐8‐derived porous carbons (ZPCs) of different sizes. We propose a mathematical model based on a spherical particle core‐shell structure, which profoundly reveals the relationship between size and specific surface area, as well as the linear relationship between specific surface area and specific capacity. Moreover, simply by reducing the size of the porous carbon, the specific capacity increased by 86.5 mAh g−1. Dynamic studies reveal that in nano‐porous carbon materials, sodium‐ion storage primarily relies on defect adsorption. Size reduction enhances physical adsorption and surface capacitance response, with ZPC‐80 exhibiting lower resistance and higher diffusion coefficient, indicating that size reduction improves electronic conductivity and charge transfer efficiency, achieving excellent reversible capacity and cycling stability. This work yields a profound insight into the dynamic characteristics of hard carbon anode materials, presenting a new perspective for the design of efficient sodium‐ion batteries.

Thermally Controlled Synthesis of Cr2(NCN)3/CrN Heterostructured Composite Anodes for High‐Performance Li‐Ion Batteries

Cr2(NCN)3 features high specific capacity and fast electrical conductivity, making it a promising anode candidate for Li‐ion batteries. However, inherent chemical and structural metastability severely restrict its capacity output and cycle life, resulting in unsatisfactory battery performance. Here we use its thermal instability characteristic and propose a thermal controlled structural coordination strategy to in‐situ construct a Cr2(NCN)3/CrN heterostructure. Systematic studies reveal the thermodynamic structural evolution of Cr2(NCN)3 under precise temperature regulation, as well as the essential relevancy between electrochemical properties and crystalline structures. An optimal Cr2(NCN)3/CrN heterostructural composite obtained at 690 °C features uniform two‐phase recombination with abundant grain boundaries enables promising electrochemical performance, exhibiting a high reversible discharge capacity (760 mAh g−1) and a good cycle performance (75% retention after 100 cycles). It is worth noting that the above performance is significantly improved over unmodified pure transition metal carbodiimides or metal nitride anodes. This study provides a simple and universal structural regulation strategy for transition metal carbodiimides that utilizes their thermal sensitivity to synchronously construct synergistic transition metal carbodiimides/transition metal nitrides heterostructures, promoting their potential applications in Li‐ion batteries.

Crystalline MnCO3@Amorphous MnOx Composite as Cathode Material for High-Performance Aqueous Zinc-Ion Batteries.

Rechargeable aqueous zinc-ion batteries (RAZIBs) have received extensive attention because of their advantages of low cost, high safety, and nontoxicity. However, problems such as dissolution of the active cathode material, dendrites/passivation of the zinc anode, and slow reaction kinetics hindered their further applications. In this work, a crystalline/amorphous composite-type material composed of crystalline MnCO3 and amorphous MnOx was prepared and used as the cathode material for RAZIBs. The MnCO3@amorphous MnOx (MnCO3@A-MnOx) composite possesses the merits of both the pure crystalline phase of MnCO3 and the amorphous phase of MnOx, which can deliver better electrochemical performance than the corresponding single component in repeated cycles. In addition, crystalline MnCO3 undergoes a complex phase transition to the active MnO2 during the first charge process, providing the composite with a stable structure and additional electrochemical capacity. The electrochemical measurement results indicate that the MnCO3@A-MnOx electrode can display high reversible discharge capacity at 0.1 A g-1, excellent rate performance at 5.0 A g-1, and long cycling stability over 2000 cycles, showing great potential as a cathode material for high-performance RAZIBs.

Carbon-coated TiNb2O7 microspheres with partial nitridation for high-performance lithium storage

TiNb2O7 has been applied to lithium-ion batteries owing to its large capacity and inherent safety, but suffers from its poor rate capability. Here, TiNb2O7 is modified through a combination of crystal-structure modification and conductive-phase coating, and C–NH3–TiNb2O7 with Ti2Nb[Formula: see text]O[Formula: see text]-type TiNb2O7 and Ti[Formula: see text][Formula: see text]Nb[Formula: see text]N/carbon double coatings is successfully synthesized. The unique Ti2Nb[Formula: see text]O[Formula: see text]-type structure of TiNb2O7 owns a large interlayer spacing, leading to fast Li[Formula: see text] diffusivity and remarkable intercalation-pseudocapacitive behavior. The conductive Ti[Formula: see text][Formula: see text]Nb[Formula: see text]N/carbon coatings result in good electrical conduction among the TiNb2O7 microspheres. Consequently, C–NH3–TiNb2O7 exhibits excellent rate capability of TiNb2O7 (large capacity percentage of 73.9% at 5C versus 0.5C). Besides the fast electrochemical kinetics, C–NH3–TiNb2O7 further exhibits large reversible capacities (237 mAh g[Formula: see text] at 0.1C and 146 mAh g[Formula: see text] at 5C) and outstanding cyclability (93.1% capacity retention after 500 cycles at 5C). These desirable electrochemical properties fully demonstrate that the C–NH3–TiNb2O7 anode material can be suitable for high-performance Li[Formula: see text]-storage.

Enhancing Rate Capability, Capacity, and Durability of Co‐Doped Germanium Phosphide Anodes for Li‐Ion Batteries

AbstractWhile germanium‐based anodes for Li‐ion batteries (LIBs) have potential to offer high energy density, their commercialization is impeded by low ionic and electronic conductivity and poor tolerance to volume change during cycling. Here a new quaternary CuGeSiP3 anode is reported to simultaneously overcome these limitations. Synthesized via ball milling process, CuGeSiP3 displays high ionic and electronic conductivity and excellent flexibility to accommodate volume change, attributed to increased structural entropy and reversible formation of favorable intermediates of both electronic and Li ion conductors, as confirmed by experimental measurements and theoretical calculations. When used as an LIB anode, CuGeSiP3 demonstrates large reversible capacity, high Coulombic efficiency, robust cycling stability, and high‐rate capability because it undergoes a reversible lithiation process that involves intercalation and conversion reaction. When composited with layered graphite, the electrode demonstrates exceptional cycling stability (1 261 mA h g−1 after 600 cycles at 400 mA g−1 and 861 mA h g−1 after 1 450 cycles at 20 00 mA g−1) and ultrahigh rate capability (448 mA h g−1 at 20 000 mA g−1). Further, the quaternary, pentanary, and hexanary cation‐disordered phosphides are also synthesized, all having similar Li‐storage superiority, implying the multiple co‐doping strategy is applicable to other material systems.

Facile Galvanic Replacement Construction of Bi@C Nanosheets Array as Binder‐Free Anodes for Superior Sodium‐Ion Batteries

AbstractBismuth (Bi) possesses an ultrahigh theoretical volume capacity (3800 mAh cm−3) and low embedding potential stimulated considerable attention as anodes for sodium‐ion batteries (SIBs). However, its practical application is still hampered by the huge volume variation during the charge/discharge process. To settle this issue, Bi@C nanosheet arrays (Bi@C‐NSA) are fabricated on copper foam via a facile galvanic replacement followed by in situ polymerization of dopamine and an annealing procedure. The carbon‐coated nanosheet array structure not only accommodates the volume expansion during cycling and maintains electrode stability, but also facilitates rapid electron/ion transport. Due to the unique structural design, this Bi@C‐NSA exhibits an impressive capacity of 315.72 mAh g−1 after 1500 cycles under 1 A g−1. Furthermore, a series of in situ/ex situ techniques reveal that this Bi@C‐NSA possesses superior reaction kinetics and undergoes a typical alloying/dealloying storage mechanism. Furthermore, Bi@C‐NSA also achieves commendable reversible capacity and cycling stability in a wide temperature range (0 °C–60 °C). Notably, the assembled Na3V2(PO4)3//Bi@C‐NSA full cell demonstrates a capacity of 325 mAh g−1 after 50 cycles at 0.05 A g−1, which promises for practical applications. This galvanic replacement strategy spearheads a way to prepare nanoarray electrodes and will accelerate the development of sodium‐ion batteries.

Interfacial bonding enhances MXene/Sb2Se3 composites toward cyclic stability and fast aluminum storage

Metal-chalcogenides have been extensively studied as electrode materials for rechargeable ion batteries due to their high theoretical specific capacity and high abundance. Although promising, these materials face challenges related to slow electrochemical kinetics, pronounced structural distortions, and severe shuttle effects. These issues have seriously hindered the practical application of metal-chalcogenides in ion batteries. This work presents a novel approach to form interfacial binding bonds and in situ generation of antimony selenide (Sb2Se3) on MXene by electrostatic adsorption. This innovative strategy enhances the reversible capacity and cycling stability of Sb2Se3 and effectively improves the electrochemical kinetics and shuttle effect. Ex-situ characterization elucidates the distinctive energy storage mechanism of the Ti3C2/Sb2Se3 cathode and the inhibitory effect of MXene on the dissolution of reaction intermediates into the electrolyte. Additionally, the improvement in charge transfer and ion diffusion due to the introduction of MXene was validated through density functional theory calculations. This work offers new insights into enhancing the stability of metal-chalcogenides and understanding the energy storage mechanism of antimony-based selenides in ion batteries.

Industrial-scale Hard Carbon Designed to Regulate Electrochemical Polarization for Fast Sodium Storage.

Given the merits of abundant resource, low cost and high electrochemical activity, hard carbons have been regarded as one of the most commercializable anode material for sodium-ion batteries (SIBs). However, poor rate capability is one of the main obstacles that severely hinder its further development. In addition, the relationships between preparation method, material structure and electrochemical performance have not been clearly elaborated. Herein, a simple but effective strategy is proposed to accurately construct the multiple structural features in hard carbon via adjusting the components of precursors. Through detailed physical characterization of the hard carbons derived from different regulation steps, and further combined with in-situ Raman and galvanostatic intermittent titration technique (GITT) analysis, the network of multiple relationships between preparation method, microstructure, sodium storage behavior and electrochemical performance have been successfully established. Simultaneously, exceptional rate capability about 108.8 mAh g-1 at 8 A g-1 have been achieved from RHC sample with high reversible capacity and desirable initial Coulombic efficiency (ICE). Additionally, the practical applications can be extended to cylindrical batterywith excellent cycle behaviors. Such facile approach can provide guidance for large-scale production of high-performance hard carbons and provides the possibility of building practical SIBs with high energy density and durability.

Fabrication of FeP2/C/CNTs@3D interconnected graphene aerogel composite for lithium-ion battery anodes and the electrochemical performance evaluation using machine learning

Featuring low cost and high theoretical capacity, phosphorus-rich iron diphosphides (FeP2) have emerged as excellent anode candidates for lithium-ion batteries. However, the typical chemical synthses involving high temperatures and toxic gases have restricted the mass production of FeP2. We now report a FeP2/C/CNTs@3D interconnected graphene aerogel composite synthesized by ball milling and low temperature heat treatment. Because of the unique microstructure and synergistic effect between well-dispersed FeP2 particles and graphene aerogel, the as-prepared FeP2/C/CNTs@GA-2.5% displays excellent lithium storage performance in terms of reversible capacity (886 mA h g−1 at 0.1 A g−1), cycling stability (476 mA h g−1 at 2 A g−1 even after 1000 cycles), and rate capability (685 mA h g−1 at 5 A g−1). Machine learning methods (decision tree and random forest algorithms) prove effective in evaluating and predicting electrochemical performance of the electrode materials.

Developing a High‐Performing Spinel LiMn2O4 Cathode Material with Unique Morphology, Fast Cycling and Scaled Manufacture

AbstractHigh power application of Li‐battery remains a challenge due to the lack of stable fast‐charging cathode materials. Lithium manganese oxide (LMO) cathode is very promising due to its high operating voltage and fast charging ability; however, the associated Mn‐dissolution is one of the main hindrances to its practical applicability. In this work, we demonstrate for the first time the use of a commercially scalable method through a proprietary Calix flash calcination (CFC) technology to develop high‐performance electrode materials where a novel CXL LMO material was manufactured and tested. CXL LMO|Li metal cell showed a reversible specific capacity of 110 mAh/g with 99 % retention after 100 cycles and showed excellent rate performance up to 20 C current rate (~20 mA/cm2 current density). CXL LMO|Graphite cell (areal capacity 1 mAh/cm2) was also reported with 86 % capacity retention over more than 500 cycles. Cross‐section morphology revealed a unique multi‐layered structure that was retained at the core of the novel LMO material. It obtained lesser Mn dissolution compared to commercial LMO. The scalable synthesis procedure through CFC technology, can be broadly applicable to produce unique electrode morphology as demonstrated here for the CXL LMO representing a promising pathway for electrode manufacturing for high‐power Li‐batteries.

Scalable Precise Nanofilm Coating and Gradient Al Doping Enable Stable Battery Cycling of LiCoO2 at 4.7 V

The quest for smart electronics with higher energy densities has intensified the development of high‐voltage LiCoO2 (LCO). Despite their potential, LCO materials operating at 4.7 V faces critical challenges, including interface degradation and structural collapse. Herein, we propose a collective surface architecture through precise nanofilm coating and doping that combines an ultra‐thin LiAlO2 coating layer and gradient doping of Al. This architecture not only mitigates side reactions, but also improves the Li+ migration kinetics on the LCO surface. Meanwhile, gradient doping of Al inhibited the severe lattice distortion caused by the irreversible phase transition of O3‐H1‐3‐O1, thereby enhanced the electrochemical stability of LCO during 4.7 V cycling. DFT calculations further revealed that our approach significantly boosts the electronic conductivity. As a result, the modified LCO exhibited an outstanding reversible capacity of 230 mAh g‐1 at 4.7 V, which is approximately 28% higher than the conventional capacity at 4.5 V. To demonstrate their practical application, our cathode structure shows improved stability in full pouch cell configuration under high operating voltage. LCO exhibited an excellent cycling stability, retaining 82.33% after 1000 cycles at 4.5 V. This multifunctional surface modification strategy offers a viable pathway for the practical application of LCO materials.

Scalable Precise Nanofilm Coating and Gradient Al Doping Enable Stable Battery Cycling of LiCoO2 at 4.7 V.

The quest for smart electronics with higher energy densities has intensified the development of high-voltage LiCoO2 (LCO). Despite their potential, LCO materials operating at 4.7 V faces critical challenges, including interface degradation and structural collapse. Herein, we propose a collective surface architecture through precise nanofilm coating and doping that combines an ultra-thin LiAlO2 coating layer and gradient doping of Al. This architecture not only mitigates side reactions, but also improves the Li+ migration kinetics on the LCO surface. Meanwhile, gradient doping of Al inhibited the severe lattice distortion caused by the irreversible phase transition of O3-H1-3-O1, thereby enhanced the electrochemical stability of LCO during 4.7 V cycling. DFT calculations further revealed that our approach significantly boosts the electronic conductivity. As a result, the modified LCO exhibited an outstanding reversible capacity of 230 mAh g-1 at 4.7 V, which is approximately 28% higher than the conventional capacity at 4.5 V. To demonstrate their practical application, our cathode structure shows improved stability in full pouch cell configuration under high operating voltage. LCO exhibited an excellent cycling stability, retaining 82.33% after 1000 cycles at 4.5 V. This multifunctional surface modification strategy offers a viable pathway for the practical application of LCO materials.