Facile Synthesis of Carbon-Coated Spinel Li4Ti5O12/Rutile-TiO2 Composites as an Improved Anode Material in Full Lithium-Ion Batteries with LiFePO4@N-Doped Carbon Cathode

Thick 3D-Printed Hierarchical Li4Ti5O12@MOF anode and Grid-Lined micropores for High-Performance Lithium-Ion batteries

Li4Ti5O12 (LTO) anode is a promising candidate for high-energy-density lithium-ion batteries (LIBs), but achieving high mass loading, a porous structure, and efficient ion transport remains a challenge. Herein, we present a high-mass-loading, hierarchically porous LTO anode with a conductive network and grid-lined micropores, embedded with a metal-organic framework (MOF) as both an electrode additive and surface protective layer. This novel structure is fabricated using extrusion-based three-dimensional (3D) printing technology. The self-standing framework provides mechanical stability and high conductivity, enabling a thick (316 μm) 3D-printed LTO@UiO-66-MOF (3D-LTO@U) anode with a mass loading of 11 mg/cm2. It delivers a high-rate capability of 161 mAh/g at 5C, an areal specific capacity of 5.37 mAh/cm2, and 78.9 % areal capacity retention after 150 cycles. Additionally, it achieves a high specific energy density of 382.35 Wh/kg. The UiO-66 MOF provides strong binding affinity, suppressing side reactions and enhancing Li-ion/electron transport within the 3D-printed interconnected channels. This improves active material utilization during charge and discharge. Furthermore, a 3D-printed full cell integrating a grid-lined 3D-LTO@U anode and a 3D-printed LiFePO4 cathode exhibits enhanced electrochemical performance. This work demonstrates an effective strategy for designing thick, high-mass-loading, and porous conductive network anodes for advanced LIBs.

The Enormous Potential of Sodium/Potassium-Ion Batteries as the Mainstream Energy Storage Technology for Large-Scale Commercial Applications

Cost-effectiveness plays a decisive role in sustainable operating of rechargeable batteries. As such, the low cost-consumption of sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) provides a promising direction for "how do SIBs/PIBs replace Li-ion batteries (LIBs) counterparts" based on their resource abundance and advanced electrochemical performance. To rationalize the SIBs/PIBs technologies as alternatives to LIBs from the unit energy cost perspective, this review gives the specific criteria for their energy density at possible electrode-price grades and various battery-longevity levels. The cost ($ kWh-1 cycle-1) advantage of SIBs/PIBs is ascertained by the cheap raw-material compensation for the cycle performance deficiency and the energy density gap with LIBs. Furthermore, the cost comparison between SIBs and PIBs, especially on cost per kWh and per cycle, is also involved. This review explicitly manifests the practicability and cost-effectiveness toward SIBs are superior to PIBs whose commercialization has so far been hindered by low energy density. Even so, the huge potential on sustainability of PIBs, to outperform SIBs, as the mainstream energy storage technology is revealed as long as PIBs achieve long cycle life or enhanced energy density, the related outlook of which is proceeded as the next development directions for commercial applications.

Oxalic acid-assisted preparation of LTO-carbon composite anode material for lithium-ion batteries

This study presents an oxalic acid-assisted method for synthesizing spinel-structured lithium titanate (Li4Ti5O12; LTO)/carbon composite materials. The Ag-doped LTO nanoparticles (NPs) are synthesized via flame spray pyrolysis (FSP). The synthesized material is used as a precursor for synthesizing the LTO-NP/C composite material with chitosan as a carbon source and oxalic acid as an additive. Oxalic acid improves the dissolution of chitosan in water as well as changes the composition and physical and chemical properties of the synthesized LTO-NP/C composite material. The oxalic acid/chitosan ratio can be optimized to improve the electrochemical performance of the LTO-NP/C composite material, and the electrode synthesized with a high mass loading ratio (5.44 mg cm-2) exhibits specific discharge capacities of 156.5 and 136 mAh g-1at 0.05 C- and 10 C-rate currents, respectively. Moreover, the synthesized composite LTO-NP/C composite material exhibits good cycling stability, and only 1.7% decrease in its specific capacity was observed after 200 charging-discharging cycles at 10 C-rate discharging current.

Spray fabrication of additive-free electrodes for advanced Lithium-Ion storage technologies

Polymer binders and carbon conductivity enhancers are inevitably required to make improvements in structural durability and electrochemical performance of lithium-ion battery (LIB) electrodes, although these additive constituents incur weight and volume penalties on the overall battery capacity. Here, additive-free electrode architectures were successfully fabricated over 20 × 20 cm2 electrode areas using a layer-by-layer spray coating approach, with the ultimate goal to boost gravimetric/volumetric electrode capacity and to reduce the total cost of LIB cells. Initially, the binder fraction of spray-coated Li4Ti5O12 (LTO) electrodes was reduced progressively, from 40 to 0 wt%. The electrochemical behavior of electrodes was then re-optimized as a proportion of conductivity enhancers within the binder-free electrode decreased to zero. Further, the otherwise identical spray coating process was applied to manufacture LiFePO4 (LFP) positive electrodes, leading to all-additive-free full-cell LIB configurations with attractive energy density of ∼310 Wh/kg and power performance of ∼1500 W/kg.

Synthesis of Porous Hollow Spheres Co@TiO2-x-Carbon Composites for Highly Efficient Lithium-Ion Batteries

The hollow TiO₂ anode material has received great attention for next-generation LIBs because of its excellent stability, environmental friendly, and low volume change during lithiation/delithiation. However, there are some problems associated with the current anatase TiO₂ anode materials in practical application owing to low lithium-ion diffusivity and poor reversible theoretical capacities. The introduction of defects has been turned out to be a significant and effective method to improve electronic conductivity, especially oxygen vacancies. In this paper, a facile hydrothermal reaction and subsequent chemical vapor deposition method were successfully used to fabricate Co@TiO_2-x-carbon hollow nanospheres. These results suggest that the synthesized product exhibits good rate performance and superior cycling stability.

Sulfurized Polyacrylonitrile as a High-Performance and Low-Volume Change Anode for Robust Potassium Storage

Potassium-ion batteries (KIBs) are considered as low-cost electrochemical energy storage technologies because of the abundant potassium resources. However, the practical applications of KIBs are mainly hampered by the unsatisfactory electrochemical performance of anode materials which often undergo large volume variations during potassiation-depotassiation, limiting their cycling life. Here, low-cost sulfurized polyacrylonitrile (S-PAN) is reported as an attractive anode candidate for KIBs. It provides a high potassium storage capacity of 569 mAh g_(S-PAN)^-1 with decent rate capability and cycling stability (no capacity loss after 1500 cycles, running time ∼188 days). Detailed ex situ spectroscopic and in situ microscopic characterizations reveal that the distinguished electrochemical performance of S-PAN is attributed to the high reversibility of its covalent C-S and S-S bonds which undergo repeated cleavage-redimerization during potassiation-depotassiation concomitant with relatively small volume variation (less than 24.2%). Subsequently, a full-cell constructed by pairing high-voltage K₂MnFe(CN)₆ cathode with high-capacity S-PAN anode demonstrates an attractive energy density (290.9 Wh kg^-1) and long-term cycling stability (1200 cycles with 95.4% capacity retention). Given the high performance and low cost of both anode and cathode materials, it is believed that the present full-cell promises it as a competitive energy storage system for the cost-sensitive grid-scale applications.

Construction and Theoretical Calculation of an Ultra-High-Performance LiVPO4F/C Cathode by B-Doped Pyrolytic Carbon from Poly(vinylidene Fluoride)

B-doped pyrolytic carbon from poly(vinylidene fluoride) (PVDF) was used to enhance the performance of a LiVPO₄F/C cathode, which is much cheaper than carbon nanotubes and graphene. The carbon layer in LVPF/C-B₃ becomes more and more regular compared with the undoped sample. The electronic conductivity, diffusion coefficient, and rate and cycle performance of the B-doped cathode are greatly improved. The capacities of LVPF/C-B₃ at 0.2C, 5C, and 15C are 148.1, 132.9, and 125.6 mAh·g^-1, which may be the best reported magnitude. The crystallite structure of LiVPO₄F/C is well maintained after 300 charge and discharge cycles. The carbonization process of PVDF is greatly accelerated. These improvements are attributed to the changes in chemical and electronic structures. The generation of BC₂O and BCO₂ results in many defective active sites, and BC₃ promotes the growth of a six-membered carbon ring. According to the first-principles approach based on density functional theory, the state density around the Fermi level of the B-doped pyrolytic carbon is increased. The electronic structure of pyrolytic carbon is transformed from a P-type semiconductor to a metal-like structure through the generation of pyridinic-like and graphitic-like B. Therefore, the electronic conductivity of LiVPO₄F/C is increased.

Rapid preparation of ultra-fine and well-dispersed SnO2 nanoparticles via a double hydrolysis reaction for lithium storage

An efficient and rapid method is reported for preparing ultra-fine and well-dispersed SnO₂ nanoparticles in a large scale. A simple double hydrolysis reaction between SnO₃^2- and Fe³⁺ ions was masterly used to form a stable colloid system, in which colloidal particles of H₂SnO₃ with negative charges and Fe(OH)₃ with positive charges electrostatically interact with each other and form honeycomb-like "core-shell" units. Through the hydrothermal reaction, the units are easily transformed into SnO₂@FeO(OH) structures. Ultra-fine and well-dispersed SnO₂ particles with less than 6 nm diameter were finally obtained with a high yield by further etching using hydrochloric acid. When used as anode materials for lithium ion batteries, the ultra-fine SnO₂ particles can be easily dispersed into the carbon networks originating from the carbon source of glucose during the hydrothermal reaction. Electrochemical tests confirmed that these ultra-fine SnO₂/C materials were endowed with excellent cyclic stability and C-rate performance. Even at a 1.56 A g^-1 (2C) high current density, the reversible capacity could be maintained at 710 mA h g^-1 after 100 cycles owing to the ultra-fine particle size of SnO₂ and the rich carbon networks.

Achieving Ultrahigh-Rate and High-Safety Li+ Storage Based on Interconnected Tunnel Structure in Micro-Size Niobium Tungsten Oxides

Developing advanced high-rate electrode materials has been a crucial aspect for next-generation lithium ion batteries (LIBs). A conventional nanoarchitecturing strategy is suggested to improve the rate performance of materials but inevitably brings about compromise in volumetric energy density, cost, safety, and so on. Here, micro-size Nb₁₄ W₃ O₄₄ is synthesized as a durable high-rate anode material based on a facile and scalable solution combustion method. Aberration-corrected scanning transmission electron microscopy reveals the existence of open and interconnected tunnels in the highly crystalline Nb₁₄ W₃ O₄₄ , which ensures facile Li⁺ diffusion even within micro-size particles. In situ high-energy synchrotron XRD and XANES combined with Raman spectroscopy and computational simulations clearly reveal a single-phase solid-solution reaction with reversible cationic redox process occurring in the NWO framework due to the low-barrier Li⁺ intercalation. Therefore, the micro-size Nb₁₄ W₃ O₄₄ exhibits durable and ultrahigh rate capability, i.e., ≈130 mAh g^-1 at 10 C, after 4000 cycles. Most importantly, the micro-size Nb₁₄ W₃ O₄₄ anode proves its highest practical applicability by the fabrication of a full cell incorporating with a high-safety LiFePO₄ cathode. Such a battery shows a long calendar life of over 1000 cycles and an enhanced thermal stability, which is superior than the current commercial anodes such as Li₄ Ti₅ O₁₂ .

Synthesis of Li4 Ti5 O12 with Tunable Morphology Using l-Cysteine and Its Enhanced Lithium Storage Properties

Nitrogen and sulfur co-doped carbon-coated Li₄ Ti₅ O₁₂ (denoted as LTO/NSC) was developed to enhance the electrochemical performance of LTO material. l-Cysteine served as both the carbon source and the heteroatom doping source. The morphology of LTO was tuned by Ti-C bond formation during carbonation process, accompanied by a change in the original orientation growth of the LTO lattice plane. Consequently, LTO transformed from nanosheets to nanoparticles. SEM data proved that the structure of LTO/NSC nanoparticles was more stable than that of LTO nanosheets after hundreds of charge/discharge process. The N,S co-doped carbon layer can moderate particle aggregation and may help to shorten the electron transport length and enhance lithium storage capacity. The structural superiority and the N,S co-doped carbon layer endows LTO/NSC particles with high reversible specific capacity (183 mA h g^-1 at 0.1 C), significantly enhanced rate capability (122 mA h g^-1 at 10 C) and excellent cycling stability (capacity retention of 96.3 % after 200 cycles) relative to these features of LTO nanosheets. Thus, LTO/NSC is a promising anode material for high-performance lithium ion batteries.

Confined Red Phosphorus in Edible Fungus Slag-Derived Porous Carbon as an Improved Anode Material in Sodium-Ion Batteries

Red phosphorus (RP) as the anode material for the sodium-ion battery (SIB) possesses a high energy density, but the poor electronic conductivity and huge volume change during Na⁺ insertion/extraction restrict its application. In this work, the edible fungus slag-derived porous carbon (PC) is adopted as a carbon matrix to combine with RP to form PC@RP composites through a facile vaporization-condensation approach. The conductive porous carbon architecture improves the transfer of electron and Na⁺ in the composite. The robust carbon framework together with the chemical bonding between PC and RP effectively buffer the huge volumetric change of RP. As a result, the PC@RP composite material delivers a specific capacity of 655.1 mA h g^-1 at 0.1 A g^-1 with a capacity retention of 87% after 100 charging/discharging cycles. In particular, the full SIB assembled with P2-Na_2/3Ni_1/3Mn_1/3Ti_1/3O₂ as the cathode material and PC@RP as the anode material exhibits a specific capacity of 77.3 mA h g^-1 (based on the mass of cathode material) at 0.5 C, and 85% capacity is retained after 100 charging/discharging cycles.

Boosting Ultra-Fast Charge Battery Performance: Filling Porous nanoLi4Ti5O12 Particles with 3D Network of N-doped Carbons

Lithium titanium oxide (Li₄Ti₅O₁₂)-based cells are a promising technology for ultra-fast charge-discharge and long life-cycle batteries. However, the surface reactivity of Li₄Ti₅O₁₂ and lack of electronic conductivity still remains problematic. One of the approaches toward mitigating these problems is the use of carbon-coated particles. In this study, we report the development of an economical, eco-friendly, and scalable method of making a homogenous 3D network coating of N-doped carbons. Our method makes it possible, for the first time, to fill the pores of secondary particles with carbons; we reveal that it is possible to cover each primary nanoparticle. This unique approach permits the creation of lithium-ion batteries with outstanding performances during ultra-fast charging (4C and 10C), and demonstrates an excellent ability to inhibit the degradation of cells over time at 1C and 45 °C. Furthermore, using this method, we can eliminate the addition of conductive carbons during electrode preparation, and significantly increase the energy density (by weight) of the anode.

Mixed-Surfactant-Assisted Synthesis of Dual-Phase Li4 Ti5 O12 -TiO2 Hierarchical Microspheres as High-Performance Anode Materials for Li-Ion Batteries

A mixed-surfactant-assisted method was developed to synthesize dual-phase Li₄ Ti₅ O₁₂ -TiO₂ hierarchical microspheres. The ratio of anionic/cationic surfactant could regulate the primary structure morphology and the dual-phase ratio of the final product, in which the primary structure morphology could be stacked nanosheets, small nanoparticles, or large nanoparticles. The sample with a primary structure morphology of small nanoparticles had the highest specific surface area of 79.38 m²  g^-1 and the best electrochemical performance because of its high Li⁺ migration rate, low polarization, and appropriate TiO₂ content. Its capacity reached 153.5 mA h g^-1 at a current rate of 40 C, and it retained nearly 100 % of its capacity after 100 cycles. A self-assembly mechanism of the mixed surfactant was highlighted to explain the formation of hierarchical microspheres. The physical and electrochemical properties of obtained material were correlated effectively.

Fabrication of Li4Ti5O12@CN Composite With Enhanced Rate Properties

Folic acid is first time applied as a carbon-nitrogen precursor to fabricate Li4Ti5O12@CN composites via ball milling Nano-TiO2, Li2CO3 and folic acid with ethanol as solvent, and then followed by heating treatment in argon. XRD, SEM, TEM, XPS, charge-discharge test and EIS are used to evaluate the influence of N-doped carbon coating on its structure, morphologies and electrochemical property. It is demonstrated that the N-doped carbon coated Li4Ti5O12 composite exhibits superior high-rate performance compared with pure Li4Ti5O12. It possesses a high discharge capacity of 174, 165 mAh g-1 at 0.5 and 10 C, respectively. Additionally, an initial specific capacity of 96.2% is obtained after 200 cycles at 10 C. The remarkable performance might be put down to the N-doped carbon layer providing efficiently electron conductive network and nanosized decreasing lithium ion diffusion path.

NiGa2O4/rGO Composite as Long-Cycle-Life Anode Material for Lithium-Ion Batteries

This work reports a novel Ga-based material, NiGa₂O₄, which is typically used as a photocatalyst for water splitting, as an anode for Li-ion battery with a long cycle life. High-surface-area reduced graphene oxide (rGO) has been used as the conductive substrate to avoid the aggregation of NiGa₂O₄ nanoparticles (NPs). Because the size and shape of NiGa₂O₄ are very sensitive to the pH of the precursor, ethylene glycol has been employed as the solvent, as well as the reduction agent to reduce GO, to avoid using extra surfactants and also to avoid the variation of pH of the precursor. The obtained NiGa₂O₄/rGO composite possesses high capacity and long cycle life (2000 cycles, 2 A/g), with NiGa₂O₄ NPs around 3-4 nm that are uniformly distributed on the rGO surface. Full cell performance with LiCoO₂ as cathode has also been studied, with the average loss of 0.04% per cycle after 100 cycles (C/2 of LiCoO₂). The long cycle life of the composite was ascribed to the self-healing feature of Ga⁰ formed during charging.

A new strategy to activate graphite oxide as a high-performance cathode material for lithium-ion batteries

Partially reduced graphite oxide was re-oxidized at a high potential of 5.2 V.

Evidence for Fast Lithium-Ion Diffusion and Charge-Transfer Reactions in Amorphous TiO x Nanotubes: Insights for High-Rate Electrochemical Energy Storage

The charge-storage kinetics of amorphous TiO _x nanotube electrodes formed by anodizing three-dimensional porous Ti scaffolds are reported. The resultant electrodes demonstrated not only superior storage capacities and rate capability to anatase TiO _x nanotube electrodes but also improved areal capacities (324 μAh cm^-2 at 50 μA cm^-2 and 182 μAh cm^-2 at 5 mA cm^-2) and cycling stability (over 2000 cycles) over previously reported TiO _x nanotube electrodes using planar current collectors. Amorphous TiO _x exhibits very different electrochemical storage behavior from its anatase counterpart as the majority of its storage capacity can be attributed to capacitive-like processes with more than 74 and 95% relative contributions being attained at 0.05 and 1 mV s^-1, respectively. The kinetic analysis revealed that the insertion/extraction process of Li⁺ in amorphous TiO _x is significantly faster than in anatase structure and controlled by both solid-state diffusion and interfacial charge-transfer kinetics. It is concluded that the large capacitive contribution in amorphous TiO _x originates from its highly defective and loosely packed structure and lack of long-range ordering, which facilitate not only a significantly faster Li⁺ diffusion process (diffusion coefficients of 2 × 10^-14 to 3 × 10^-13 cm² s^-1) but also more facile interfacial charge-transfer kinetics than anatase TiO _x.

Polyanthraquinone-Triazine-A Promising Anode Material for High-Energy Lithium-Ion Batteries

A novel covalent organic framework polymer material that bears conjugated anthraquinone and triazine units in its skeleton has been prepared via a facile one-pot condensation reaction and employed as an anode material for Li-ion batteries. The conjugated units consist of C═N groups, C═O groups, and benzene groups, which enable a 17-electron redox reaction with Li per repeating unit and bring a theoretical specific capacity of 1450 mA h g^-1. The polymer also shows a large specific surface area and a hierarchically porous structure to trigger interfacial Li storage and contribute to an additional capacity. The highly conductive conjugated polymer skeleton enables fast electron transport to facilitate the Li storage. In this way, the polymer electrode shows a large specific capacity and favorable cycling and rate performance, making it an appealing anode choice for the next-generation high-energy batteries.

Pine-Needle-Like Cu-Co Skeleton Composited with Li4 Ti5 O12 Forming Core-Branch Arrays for High-Rate Lithium Ion Storage

High-performance of lithium-ion batteries (LIBs) rely largely on the scrupulous design of nanoarchitectures and smart hybridization of bespoke active materials. In this work, the pine-needle-like Cu-Co skeleton is reported to support highly active Li₄ Ti₅ O₁₂ (LTO) forming Cu-Co/LTO core-branch arrays via a united hydrothermal-atomic layer deposition (ALD) method. ALD-formed LTO layer is uniformly anchored on the pine-needle-like heterostructured Cu-Co backbone, which consists of branched Co nanowires (diameters in 20 nm) and Cu nanowires (250-300 nm) core. The designed Cu-Co/LTO core-branch arrays show combined advantages of large porosity, high electrical conductivity, and good adhesion. Due to the unique positive features, the Cu-Co/LTO electrodes are demonstrated with enhanced electrochemical performance including excellent high-rate capacity (155 mAh g^-1 at 20 C) and noticeable long-term cycles (144 mAh g^-1 at 20 C after 3000 cycles). Additionally, the full cell assembled with activated carbon positive electrode and Cu-Co/LTO negative electrode exhibits high power/energy densities (41.6 Wh kg^-1 at 7.5 kW kg^-1 ). The design protocol combining binder-free characteristics and array configuration opens a new door for construction of advanced electrodes for application in high-rate electrochemical energy storage.

Nitrogen-Doped Perovskite as a Bifunctional Cathode Catalyst for Rechargeable Lithium-Oxygen Batteries

In this work, nitrogen-doped LaNiO₃ perovskite was prepared and studied, for the first time, as a bifunctional electrocatalyst for oxygen cathode in a rechargeable lithium-oxygen battery. N doping was found to significantly increase the Ni³⁺ contents and oxygen vacancies on the bulk surface of the perovskite, which helped to promote the oxygen reduction reaction and oxygen evolution reaction of the cathode and, therefore, enabled reversible Li₂O₂ formation and decomposition on the cathode surface. As a result, the oxygen cathodes loaded with N-doped LaNiO₃ catalyst showed an improved electrochemical performance in terms of discharge capacity and cycling stability to promise practical Li-O₂ batteries.

Preparation of Lithium Titanate/Reduced Graphene Oxide Composites with Three-Dimensional "Fishnet-Like" Conductive Structure via a Gas-Foaming Method for High-Rate Lithium-Ion Batteries

With use of ammonium chloride (NH₄Cl) as the pore-forming agent, three-dimensional (3D) "fishnet-like" lithium titanate/reduced graphene oxide (LTO/G) composites with hierarchical porous structure are prepared via a gas-foaming method. Scanning electron microscopy and transmission electron microscopy images show that, in the composite prepared with the NH₄Cl concentration of 1 mg mL^-1 (1-LTO/G), LTO particles with sizes of 50-100 nm disperse homogeneously on the 3D "fishnet-like" graphene. The nitrogen-sorption analyses reveal the existence of micro-/mesopores, which is attributed to the introduction of NH₄Cl into the gap between the graphene sheets that further decomposes into gases and produces hierarchical pores during the thermal treatment process. The loose and porous structure of 1-LTO/G composites enables the better penetration of electrolytes, providing more rapid diffusion channels for lithium ion. As a result, the 1-LTO/G electrode delivers an ultrahigh specific capacity of 176.6 mA h g^-1 at a rate of 1 C. Even at 3 and 10 C, the specific capacity can reach 167.5 and 142.9 mA h g^-1, respectively. Moreover, the 1-LTO/G electrode shows excellent cycle performance with 95.4% capacity retention at 10 C after 100 cycles. The results demonstrate that the LTO/G composite with these properties is one of the most promising anode materials for lithium-ion batteries.

Li4 Ti5 O12 Anode: Structural Design from Material to Electrode and the Construction of Energy Storage Devices

Spinel Li₄ Ti₅ O₁₂ , known as a zero-strain material, is capable to be a competent anode material for promising applications in state-of-art electrochemical energy storage devices (EESDs). Compared with commercial graphite, spinel Li₄ Ti₅ O₁₂ offers a high operating potential of ∼1.55 V vs Li/Li⁺ , negligible volume expansion during Li⁺ intercalation process and excellent thermal stability, leading to high safety and favorable cyclability. Despite the merits of Li₄ Ti₅ O₁₂ been presented, there still remains the issue of Li₄ Ti₅ O₁₂ suffering from poor electronic conductivity, manifesting disadvantageous rate performance. Typically, a material modification process of Li₄ Ti₅ O₁₂ will be proposed to overcome such an issue. However, the previous reports have made few investigations and achievements to analyze the subsequent processes after a material modification process. In this review, we attempt to put considerable interest in complete device design and assembly process with its material structure design (or modification process), electrode structure design and device construction design. Moreover, we have systematically concluded a series of representative design schemes, which can be divided into three major categories involving: (1) nanostructures design, conductive material coating process and doping process on material level; (2) self-supporting or flexible electrode structure design on electrode level; (3) rational assembling of lithium ion full cell or lithium ion capacitor on device level. We believe that these rational designs can give an advanced performance for Li₄ Ti₅ O₁₂ -based energy storage device and deliver a deep inspiration.

Preparation of Ce- and La-Doped Li₄Ti₅O12 Nanosheets and Their Electrochemical Performance in Li Half Cell and Li₄Ti₅O12/LiFePO₄ Full Cell Batteries

This work reports on the synthesis of rare earth-doped Li₄Ti₅O₁₂ nanosheets with high electrochemical performance as anode material both in Li half and Li₄Ti₅O₁₂/LiFePO₄ full cell batteries. Through the combination of decreasing the particle size and doping by rare earth atoms (Ce and La), Ce and La doped Li₄Ti₅O₁₂ nanosheets show the excellent electrochemical performance in terms of high specific capacity, good cycling stability and excellent rate performance in half cells. Notably, the Ce-doped Li₄Ti₅O₁₂ shows good electrochemical performance as anode in a full cell which LiFePO₄ was used as cathode. The superior electrochemical performance can be attributed to doping as well as the nanosized particle, which facilitates transportation of the lithium ion and electron transportation. This research shows that the rare earth doped Li₄Ti₅O₁₂ nanosheets can be suitable as a high rate performance anode material in lithium-ion batteries.