High-performance Lithium-ion Batteries Research Articles

Surface Engineering of Cathode Materials: Enhancing the High Performance of Lithium-Ion Batteries.

The development and application of lithium-ion batteries present a dual global prospect of opportunity and challenge. With conventional energy sources facing reserve shortages and environmental issues, lithium-ion batteries have emerged as a transformative technology over the past decade, owing to their superior properties. They are poised for exponential growth in the realms of electric vehicles and energy storage. The cathode, a vital component of lithium-ion batteries, undergoes chemical and electrochemical reactions at its surface that directly impact the battery's energy density, lifespan, power output, and safety. Despite the increasing energy density of lithium-ion batteries, their cathodes commonly encounter surface-side reactions with the electrolyte and exhibit low conductivity, which hinder their utility in high-power and energy-storage applications. Surface engineering has emerged as a compelling strategy to address these challenges. This paper meticulously examines the principles and progress of surface engineering for cathode materials, providing insights into its potential advancements and charting its development trajectory for practical implementation.

Lithium-rich manganese-based layered oxide cathode materials for lithium-ion batteries modified by MoS2 coatings with two-dimensional graphene-like structures

Lithium-rich manganese-based layered oxide cathode materials (LRMCs) have some unique advantages such as high theoretical capacity (≥ 250 mAh g-1) and high energy density. Therefore, they are deemed as a kind of cathode material for lithium-ion batteries with an excellent prospect of application. However, the redox of oxygen anion is able to generate irreversible lattice oxygen loss, leading to the irreversible loss of capacity, bringing about a sharp drop in working voltage, and seriously restricting the commercialization of LRMCs. In this paper, MoS2 coating with two-dimensional graphene-like structure is coated on the surface of LRMCs material for improving the cycling stability and rate performance of the material. The MoS2 coating can provide a two-dimensional diffusion channel for the migration of lithium-ions, which facilitates the fast release of lithium-ions during cycling process. The results show that the first discharge capacity, initial Coulomb efficiency and rate performance of LRMCs were improved. When the current density is 1C, the first discharge specific capacity of LRMCs@MoS2 reaches 227.69 mAh g-1, and the capacity retention ratio is 84.98% after 100 cycles. When the current density is 5C, it can still provide a discharge specific capacity of 137.87 mAh g-1, demonstrating excellent electrochemical performance. This study comes up a simple and practical idea to realize the modification of cathode materials for high performance lithium-ion batteries.

Micron silicon-oxide-carbon coated with TiOx(OH)y layer as better performance anode for lithium-ion batteries

Micron-silicon based material is a promising anode material for high performance lithium batteries due to its ultra-high specific capacity. However, the volume expansion exceeds 300% during charging and discharging, resulting in the collapse of the electrode structure and a rapid decline in electrochemical performance. Coating the surface of silicon-based materials with flexible ionic conductors is an effective method to maintain their high capacity and suppress swelling. Here, to further improve the electrochemical performance of silicon-based materials, we have deposited a titanate-type ionic conductor layer on a micron-sized silicon-carbon oxide (SiOX-C) material to synthesize the SiOX-C@TiOx(OH)y material. The TiOx(OH)y layer not only exhibits the elastic properties of a superpolymer to mitigate swelling strain, but also has a fast capacitance effect to improve its rate performance. In addition, the interfacial charge transport of SiOX-C@TiOx(OH)y is enhanced due to the structural diversity of the TiOx(OH)y layer. For the above mechanisms, the SiOX-C@TiOx(OH)y has a specific capacity of 278.3 mAh g−1 under high current of 3500 mA g−1. Meanwhile, the SiOX-C@TiOx(OH)y with the capacity retention of 67% is achieved at 2000 mA g−1 after 100 cycles.

Control of N/P ratios and cut-off voltage for Silicon-Based Li-ion batteries

High-energy density and unwavering safety standards form the cornerstone of new energy vehicle development, necessitating the design of power batteries that seamlessly integrate these critical qualities. Key to this endeavor is the enhancement of energy density at the architectural level, focusing on the optimization of the N/P ratio—a move that demands a holistic evaluation extending beyond mere comparisons of cathode and anode capacities to include initial efficiency, and both reversible and irreversible capacities. Departing from traditional N/P ratio designs requires meticulous optimization. This research introduces a novel N/P ratio design methodology, termed the “Water Cup Model”, for lithium-ion batteries (LIBs), effectively addressing capacity loss issues endemic to conventional designs. This approach, under consistent cathode material and areal capacity conditions, increases the batteries’ specific energy by approximately 5 Wh/kg, without compromising safety. Further innovation is achieved by incorporating a voltage regulation coefficient, λ, allowing for precise adjustment of the cut-off discharge voltage and facilitating the selection of high-performance silicon-based anode materials. Comparative assessments of energy density and cycling performance affirm the superiority of our optimized N/P ratio strategy against conventional methods. This strategy’s core lies in its capacity to significantly boost energy density without extensive modifications to the battery’s internal makeup, relying solely on the precise management of the N/P ratio to ensure safety is not compromised by energy density enhancements. This seminal work lays down a cost-effective, robust framework for advancing high-performance LIB technology, contributing pivotal insights to the field.

Engineering the solvent-anion interactions of LiTFSI-based dual-salt electrolytes to sustain high-performance NCM622 cathodes

Electrolytes play a vital role in determining the performances of lithium-ion batteries (LIBs), especially the high-voltage LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode in LiTFSI-based electrolytes. Herein, we report a high-capacity and stable NCM622 cathode that can be realized in LiTFSI-based (named T) carbonate electrolytes by tuning the intermolecular interactions using the added LiDFOB (named D). In the 1 M dual-salt electrolyte, the cathode failure and Al corrosion are suppressed in the 4.5 V-NCM622||Li batteries, because a uniform interfacial layer and weaker Li+-solvent interactions are built to inhibit the parasitic reactions. As a result, the capacity retention reaches 94.68% after 200 cycles and the 10 C-rate capacity is about 160 mA h g-1 in the 1 M T+D dual-salt electrolyte. Unlike the commonly used electrolyte, the FEC additive increases the de-solvation barrier and disturbs the cycle stability in (T+D) dual-salt systems. Density functional theory (DFT) calculation and nuclear magnetic resonance (NMR) spectra reveal that the additive FEC changes the solvent-solvent and solvent-anion interactions in the presence of T+D, which weakens the electrolyte-cathode compatibility. This work indicates that regulating the solvation structure and interfacial chemistry from solvent-solvent/anion interactions is promising for designing high-performance LIBs by using dual‐salt electrolytes.

Boosting cationic and anionic redox activity of Li-rich layered oxide cathodes via Li/Ni disordered regulation

Lithium-rich layered oxides (LLOs) are increasingly recognized as promising cathode materials for next-generation high-energy-density lithium-ion batteries (LIBs). However, they suffer from voltage decay and low initial Coulombic efficiency (ICE) due to severe structural degradation caused by irreversible O release. Herein, we introduce a three-in-one strategy of increasing Ni and Mn content, along with Li/Ni disordering and TM–O covalency regulation to boost cationic and anionic redox activity simultaneously and thus enhance the electrochemical activity of LLOs. The target material, Li1.2Ni0.168Mn0.558Co0.074O2 (L1), exhibits an improved ICE of 87.2% and specific capacity of 293.2 mA h g−1 and minimal voltage decay of less than 0.53 mV/cycle over 300 cycles at 1 C, compared to Li1.2Ni0.13Mn0.54Co0.13O2 (Ls) (274.4 mA h g−1 for initial capacity, 73.8% for ICE and voltage decay of 0.84 mV/cycle over 300 cycles at 1 C). Theoretical calculations reveal that the density of states (DOS) area near the Fermi energy level for L1 is larger than that of Ls, indicating higher anionic and cationic redox reactivity than Ls. Moreover, L1 exhibits increased O-vacancy formation energy due to higher Li/Ni disordering of 4.76% (quantified by X-ray diffraction Rietveld refinement) and enhanced TM–O covalency, making lattice O release more difficult and thus improving electrochemical stability. The increased Li/Ni disordering also leads to more Ni2+ presence in the Li layer, which acts as a pillar during Li+ de-embedding, improving structural stability. This research not only presents a viable approach to designing low-Co LLOs with enhanced capacity and ICE but also contributes significantly to the fundamental understanding of structural regulation in high-performance LIB cathodes.

Defect-driven ion storage on hexagonal boron nitride for fire-safe and high-performance lithium-ion batteries

The mass market adoption of electric vehicles has increased the risk of safety concerns, such as overheating and flammability. Rational design of fire-safe and high-capacity anodes with thermal tolerance, capable of fast-charging and long cycle-life, is crucial for the development of next generation Li-ion batteries operating under extreme conditions. Here we report a defect engineered hexagonal boron nitride (hBN) anode to mediate the safety dilemma. We demonstrate that the defects generated via cryomilling catalyze the reversible LiF formation and enable the pseudocapacitive type Li-ion storage on hBN. The non-flammability and excellent thermal tolerance of hBN allows high specific capacity (880 mAh/g @ 25 mA/g), rate performance (480 mAh/g @ 5 A/g) and stable cycling (5000 cycles) at 60 °C. The Li-ion full-cell with the defective hBN anode and the conventional cathode (LiNiMnCoO2) delivers significantly higher energy (400 Wh kg−1) and power density (1 kW kg−1) when compared to graphite/LiNiMnCoO2 full-cells (121 Wh kg−1 and 250 W kg−1). First-principles calculations confirm that nitrogen antisite (NBVN) defects are responsible for the electrochemical activation of otherwise inactive hBN. The strategy of defect-induced electrochemical activation opens up new avenues in the design of high-performance electrode materials for numerous secondary batteries.

Comparative Investigation of Water-Based CMC and LA133 Binders for CuO Anodes in High-Performance Lithium-Ion Batteries.

Transition metal oxides are considered to be highly promising anode materials for high-energy lithium-ion batteries. While carbon matrices have demonstrated effectiveness in enhancing the electrical conductivity and accommodating the volume expansion of transition metal oxide-based anode materials in lithium-ion batteries (LIBs), achieving an optimized utilization ratio remains a challenging obstacle. In this investigation, we have devised a straightforward synthesis approach to fabricate CuO nano powder integrated with carbon matrix. We found that with the use of a sodium carboxymethyl cellulose (CMC) based binder and fluoroethylene carbonate additives, this anode exhibits enhanced performance compared to acrylonitrile multi-copolymer binder (LA133) based electrodes. CuO@CMC electrodes reveal a notable capacity ~1100 mA h g-1 at 100 mA g-1 following 170 cycles, and exhibit prolonged cycling stability, with a capacity of 450 mA h g-1 at current density 300 mA g-1 over 500 cycles. Furthermore, they demonstrated outstanding rate performance and reduced charge transfer resistance. This study offers a viable approach for fabricating electrode materials for next-generation, high energy storage devices.

Triazine-Based Large-Sized Single-Crystalline Two-Dimensional Covalent Organic Framework for High-Performance Lithium-ion Batteries.

A large-sized single crystalline 2D COFs with excellent crystallinity and stability was prepared through the traditional thermal solvent method. The electrochemical performance can be significantly enhanced using a straightforward hybrid approach that involves in-situ growth of the 2D COFs on multi-walled carbon nanotubes (MWCNTs). Both the advantages of COFs and CNTs are mutually enhanced. The single-crystalline feature of the obtained COFs improves the structural integrity and brings excellent chemical and electrochemical stabilities for lithium-ion battery applications. The resultant COF-CNT core-shell hybrids greatly improved the conductivity and demonstrated excellent lithium-ion storage performance with a high capacity of 228 mAh g-1 (0.2 A g-1).

Co(OH)2 derived from in-situ conversion of metal Co confined within a spongy porous carbon for high-performance lithium-ion battery anode

Fabricating Co(OH)2/C composites is considered as an efficient solution to poor conductivity and significant volume expansion issues of Co(OH)2 anode during cycle, but the easy conversion of Co(OH)2 into cobalt oxides during thermal treatment process limits structural design of materials and selection of carbon precursors, hence constricting the diversified design and structural optimization of the Co(OH)2/C composites. Herein, a distinctive method is demonstrated to embed Co(OH)2 nanoparticles (NPs) into a porous carbon (PC), which involves in-situ conversion of the metallic Co NPs confined within a spongy PC into Co(OH)2 NPs by simple H2O2 treatment under hydrothermal conditions. The as-prepared composite is referred as Co(OH)2@PC. This method avoids the conversion of Co(OH)2 into cobalt oxides during preparation of Co(OH)2/C. Moreover, the findings verify that the rational combination of porous carbon and nanoscale Co(OH)2 NPs endows Co(OH)2@PC with enhanced conductivity, improved Li+ diffusion coefficient, high capacitive contribution, stable structure and a LiF-rich SEI layer during cycle. As a result, the Co(OH)2@PC exhibits outstanding electrochemical performance, displaying 815.8 and 543.4 mAh g−1 after 120 cycles at 0.2 and 1.0 A g−1, respectively. This work may broaden the way for diversified design and structural optimization of Co(OH)2/C anodes of lithium-ion batteries.

Combination of silicene and boronene as a potential anode material for high-performance lithium-ion batteries: Insights from first principles

Material design is essential for the development and preparation of new materials. In this paper, a new two-dimensional heterostructure material (B@Si) consisting of boronene and silicene is designed and used as an anode material for lithium-ion batteries in order to improve the performance of lithium-ion batteries, and the structural properties, stability, electronic properties, and performance as an anode material for lithium-ion batteries are systematically investigated by first-principle calculations of the B@Si heterostructure. The results show that the B@Si heterostructure is energetically, thermodynamically and dynamically stable, and although the Dirac cone in the energy band structure of silicene disappears after the formation of the heterojunction, the overall electrical conductivity of the material improves considerably and the electron transport rate is faster. Due to the synergistic effect, Li has more stable adsorption sites and lower diffusion barriers than boronene and silicene in the B@Si heterostructure, higher theoretical specific capacity (1208 mAhg−1), and stronger mechanical properties (C11 = 296.6 N/m, C22 = 142.8 N/m). The volume expansion in the fully lithiated state is also only 8 %. These advantages indicate that B@Si heterostructures are good potential anode materials for high-performance Li-ion batteries.

Construction of 2D/1D rGO/H2Ti3O7 composite as anode for high performance lithium-ion batteries

Ultrafine one-dimensional (1D) H2Ti3O7 nanowires were prepared by a hydrothermal reaction with high concentration of KOH as base source. Then 2D/1D rGO/H2Ti3O7 architecture was constructed and investigated as the anode material for lithium-ion batteries. Benefiting from the addition of rGO nanosheets and the retention of ultrafine 1D H2Ti3O7 nanowires, the rGO/H2Ti3O7 electrode presented superior electrochemical performance with excellent rate capability, long cycling stability and high capacity in half cells. It delivered high reversible capacities of 274 mAh g−1 at 0.1 A g−1 and 163 mAh g−1 at 1 A g−1, as well as a long-term cycling performance (259.3 mAh g−1 at 0.2 A g−1 after 1000 cycles). The excellent electrochemical performance of the composite can be attributed to the unique architecture with smaller diameter of 1D H2Ti3O7 nanowires and conductive rGO nanosheets to shorten the transmission distance of electrons and Li+ and improve the electrical conductivity in rGO/H2Ti3O7 composite.

Electrochemical-mechanical coupled lithium growth in fiber-structured electrodes

Lithium plating (stripping) on the electrode surface and embedding inside the electrode occur simultaneously in lithium-ion batteries during fast (dis)charging, which involves both deposition and diffusion mechanisms. The paper presents a developed finite-element procedure that accommodates these two mechanisms, facilitating the modeling of the (dis)charging process in electrodes. The framework, which integrates interface electrochemical reaction kinetics, electrochemical-mechanical coupling, comprehensive constitutive models for silicon/graphite/lithium, and a surface growth re-meshing algorithm, is capable of real-time simulation of the surface deposition and coupled diffusion-deformation processes on the electrode substrate. We examined the effects of charging rate, diffusion rate and volumetric expansion on the stress of the plated lithium layer in a fiber-structured electrode. By accounting for creep in lithium metal and subsequent stress relaxation, we obtained time-dependent stress profiles in the plated lithium layer. As an application, we quantified electroplating stresses in both fiber-structured graphite and silicon electrodes. Taking the silicon electrode as a model case, we demonstrate that hollow fiber structural electrodes can also alleviate the stress in the surface lithium-plating layer. The numerical framework may be further applied to explorations for the optimization of electrode structures in advanced high performance lithium-ion batteries.

CoO nanoparticles anchored on porous pinecone-derived activated carbon as anodes for high-performance lithium and sodium-ion batteries

In this work, a new nanocomposite system based on CoO nanoparticles (NPs) anchored on pinecone-derived activated carbon (PAC), denoted as CoO(x)@PAC, is synthesized by facile ball-milling and sonication processes followed by annealing. H3PO4 is employed as an activation agent to activate the porous carbon derived from pinecone. The loading amount of CoO is varied to obtain the optimum electrochemical performances. Among the nanocomposites, the CoO(20)@PAC delivers a discharge capacity of 886 mA h g−1 after 100 cycles at a current density of 100 mA g−1 when employed as an anode in lithium-ion batteries (LIBs). At higher current rate of 1000 mA g−1, the anode provides an enhanced discharge capacity of 456.6 mA h g−1 after 200 cycles with 99 % capacity retention compared to the 4th cycle capacity. In sodium-ion batteries (SIBs), the CoO(20)@PAC anode delivers a discharge capacity of 290 mA h g−1 at 50 mA g−1. The same nanocomposite anode provides a discharge capacity of 120 mA h g−1 after 900 cycles at a current density of 500 mA g−1. The CoO(20)@PAC nanocomposite shows a great potential as an anode for both LIBs and SIBs, due to its higher capacity, exceptional rate capability, longer cycle life, and a Coulombic efficiency exceeding 99 %.

One step for the construction of MnCO3-Mn3O4 composite for the high-performance lithium-ion batteries

In this work, MnCO3-Mn3O4 composite materials were prepared by one-step solvothermal method. The structure, morphology and chemical composition were characterized and analyzed. As the anode materials of lithium-ion batteries, the formed MnCO3-Mn3O4 composites on the basis of initial KMnO4/DMF weight ratio of 1:40 and 1:20 delivered the specific discharge capacities of 654.8 and 598.7 mA h g−1 after 100 cycles at a current density of 1.0 A g−1. The testing results indicate that MnCO3-Mn3O4 composite has significant advantage in electrochemical lithium storage capacity and can be utilized as one prospective anode material for the high performance lithium-ion batteries.

Self-assembled Si-based anode combined with electrostatic spinning method to realize high-performance lithium-ion batteries

Addressing the volume expansion when silicon and metal oxides alone are used as anode materials for lithium-ion batteries. This study used a simple self-assembly method and electrostatic spinning technique to prepare silicon@copper oxide@carbon nanofibres (CNFs) anodes with dual modification. The high rigidity of metal oxide CuO and the excellent cycling stability of CNFs effectively reduce the buildup of silicon particles, alleviate the volume expansion effect, and improve the electrical conductivity, which leads to better cycling stability and larger specific capacity of lithium-ion batteries. An excellent reversible specific capacity of 748.5 mAh g‐1−1 was observed after 800 cycles at a high current density of 1 A g−1. In addition, the surface of Si@CuO@CNFs electrodes remains smooth and undamaged after 800 cycles, and the increase in cross-sectional thickness is about 68 %, which is significantly smaller than the 300 % increase in cross-sectional thickness of pure Si anode and effectively improves the specific capacity of Li-ion batteries. This research optimizes the design of silicon-based anode materials with simple and mature process technology, which makes an indispensable contribution to developing high-efficiency, long-life, and environmentally friendly lithium-ion batteries. The easy availability and non-polluting nature of the materials used also effectively reduce the reliance on rare or expensive elements, minimize the production process's environmental impact, and vigorously promote the global energy transition and low-carbon green development strategy.

PVP-assisted synthesis of NiSnO3 firmly anchored on graphene as a high-performance lithium battery: A combination of theoretical and experimental study.

Tiny NiSnO3 nanoparticles with the assistance of polyvinylpyrrolidone (PVP) are prepared to uniformly and stably "bond" on the surface of graphene to form a stable NiSnO3/RGO-PVP structure. At the same time, the excellent performance of lithium-ion batteries (LIBs) with the use of NiSnO3/RGO-PVP structure is verified through a dual combination of experiment and theory. The resulting NiSnO3/RGO-PVP structure enhanced the performance of LIBs with high cycling stability and better rate capability; even after undergoing rate performance tests at different high current densities, the NiSnO3/RGO-PVP electrode can still reach a capacity of 624 mA h g-1 at 200 mA g-1 after 400 cycles. The superior electrochemical performance of NiSnO3/RGO-PVP nanocomposites can be attributed to the synergistic effects between tiny NiSnO3 nanoparticles synthesized with the assistance of PVP and RGO, which can be verified through first-principles calculations based on DFT. The charge transfer between NiSnO3 and RGO through an electron density difference indicates a strong interaction between the two. Meanwhile, the low adsorption energies (-3.914, -0.77, and -0.65eV), low diffusion barriers (0.025, 0.49, and 0.141eV), and high diffusion coefficients (1.79 × 10-3, 5.38 × 10-11, and 2.97 × 10-5cm2s-1) of lithium ions at three different positions indicate the excellent rate performance of the NiSnO3/RGO-PVP heterostructure, which is consistent with experimental results. This work analyzes the excellent electrochemical performance of NiSnO3/RGO-PVP from the experimental results and supports the reliability of the experimental results through theoretical calculations.

Formation of hollow stepped FePBA@rGO anode for high-performance lithium-ion batteries

Prussian blue and its analogues (PBAs) have been considered promising anode materials for lithium-ion batteries (LIBs) owing to their high theoretical capacity and cost-effectiveness. However, they often encounter challenges such as poor electronic conductivity and structural instability. Herein, we introduce a hollow stepped FePBA framework structure coated with reduced graphene oxide (FePBA@rGO). This sophisticated design significantly improves electronic conductivity and optimizes the diffusion pathways for lithium ions, leading to exceptional cycling stability and rate performance. The FePBA@rGO-15 anode developed in this study shows a notable rate capability of 294 mAh g−1 at a current density of 2 A g−1. More significantly, it demonstrates exceptional lithium storage performance, maintaining a capacity of 1245 mAh g−1 after 600 cycles at a current density of 1 A g−1. Density functional theory simulations further support our findings by illustrating that the robust interface between FePBA and rGO significantly accelerates the reactions kinetics of Li+ within the FePBA framework. This study represents a significant advancement towards improving the capacity and cycling stability of PBA-based anode materials, offering promising prospects for future battery applications.

Green Phytic Acid-Assisted Synthesis of LiMn1-xFexPO4/C Cathodes for High-Performance Lithium-Ion Batteries.

As a promising cathode material, olivine-structured LiMnPO4 holds enormous potential for lithium-ion batteries. Herein, we demonstrate a green biomass-derived phytic-acid-assisted method to synthesize a series of LiMn1-xFexPO4/C composites. The effect of Fe doping on the crystal structure and morphology of LiMnPO4 particles is investigated. It is revealed that the optimal Fe doping amount of x = 0.2 enables a substantial enhancement of interfacial charge transfer ability and Li+ ion diffusion kinetics. Consequently, a large reversible capacity output of 146 mAh g-1 at 0.05 C and a high rate capacity of 77 mAh g-1 at 2 C were acquired by the as-optimized LiMn0.8Fe0.2PO4/C cathode. Moreover, the LiMn0.8Fe0.2PO4/C delivered a specific capacity of 68 mAh g-1 at 2 C after 500 cycles, with a capacity retention of 88.4%. This work will unveil a green synthesis route for advancing phosphate cathode materials toward practical implementation.

Retarding the capacity fading and voltage decay of Li-rich Mn-based cathode materials via a compatible layer coating for high-performance lithium-ion batteries.

Li-rich Mn-based layered oxides have been considered as the most promising cathode candidate for high energy density lithium ion batteries. However, the practical application of Li-rich Mn-based layered oxides is hindered due to the capacity fading and voltage decay accompanied with structure transition from the layered structure to spinel phase during cycling. Herein, a facile surface structure repair via Ce modification is reported. The structural analysis of the bulk and coating layer was carried out using XRD, XPS, SEM and TEM, which confirmed the successful doping of Ce and formation of a Li2CeO3 coating on the surface. The modified sample LLO-2 delivers a discharge specific capacity of 263.5 mA h g-1 at 0.1C and capacity retention rate with 88.1% at 0.2C after 100 cycles compared to 250.2 mA h g-1 and 75.6% for the pristine sample. The enhanced performance could be because Ce doping enlarges the lattice parameter, which may contribute to accelerating the Li+ diffusion rate. Moreover, the newly formed Li2CeO3 coating with oxygen vacancies could inhibit the loss of lattice oxygen and protect the electrode surface by suppressing the attack from the electrolyte. This work provides an effective approach to design Li-rich Mn-based layered oxides with improved electrochemical performance.