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LiFePO 4 /Very-few-layer-graphene (LFP/VFLG) composites have been prepared using the sol-gel method for lithium-ion battery cathode. VFLG dominated by 1∼3 layers was obtained from an economical and environmentally benign process. Structural properties of LFP/VFLG composites were studied using Fourier-transform infrared spectra (FTIR) spectroscopy, X-ray diffractometry (XRD), high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy, while the electrochemical performance was measured using galvanostatic discharge, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) tests. The FTIR analysis confirmed that incorporating VFLG neither affected the chemical structure of LiFePO 4 nor initiated any side reactions during the LiFePO 4 formation reaction. The XRD results showed that LFP/VFLG composites had better lattice parameters, crystallinity, and phase purity than LiFePO 4 without VFLG addition. The Raman spectroscopy analysis indicated that LFP/VFLG composites had a lower disorder in the carbon arrangement. HRTEM results indicated that a VFLG was successfully wrapped around the LFP particle offers a versatile way to enhanced electrochemical performance of LFP/VFLG composites. The galvanostatic discharge profiles showed an enhancing specific discharge capacity of up to 58.3% after incorporating VFLG. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests revealed that LFP/VFLG delivered small polarization, low inner resistance, high electrochemical reaction reversibility, and high lithium-ion diffusion coefficient. VFLG is a promising additive to improve the structural and electrochemical properties of the LiFePO 4 cathode of lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Optimizing the structure of materials has proven to be an efficient solution for improving the electrochemical performance of lithium-ion batteries. In this work, SnO 2 -WS 2 -CNTS (SWC) ternary composites were prepared by hydrothermal and ball milling methods to first obtain SnO 2 -WS 2 mixture, which was then embedded on CNTS to form a special multi-level structure. Due to the special 2D structure of transition metal sulfide WS 2 and CNTS, the de-intercalation speed of lithium ions is greatly increased and the inherent particle aggregation phenomenon of SnO 2 is weakened. The three materials show their advantages while compensating for each other's disadvantages, forming an interesting synergistic effect which results in extremely stable anode materials. At 0.2Ag-1, the capacity of SWC reaches 930.71 mAhg-1 after 100 cycles, and reaches 1043 mAhg-1 after 1000 cycles at 1.0Ag-1. It is worth noting that after multiple cycles, SWC still exhibits an extremely stable state in the SEM image. The above results confirm that the special structure of SWC leads to excellent electrochemical performance, and its simple preparation method makes it a potential leading battery anode material in the future. [ABSTRACT FROM AUTHOR]

Currently, the safety of lithium-ion batteries has attracted much attention. All-solid-state batteries (ASSBs) are promising replacements for liquid-electrolyte lithium-ion batteries due to their high energy density and excellent safety. The choice of electrolyte is the most critical part of ASSBs. Li 7 La 3 Zr 2 O 12 (LLZO)-based solid-state electrolytes (SSEs) render high energy density, wide electrochemical window and high lithium-ion mobility. However, their low lithium-ion conductivity compared with liquid organic electrolytes and rigid interfacial contact at electrode/electrolyte interface mainly hinder the development of LLZO-based ASSBs. Herein, we review recent progress in the area of LLZO-based SSEs by discussing the structure and transport mechanism of lithium (Li)-ions of LLZO. Also, we summarize bottleneck problems and corresponding solutions, providing theoretical basis and technical support for the development of LLZO-based ASSBs. Finally, future prospects of LLZO-based ASSBs are discussed in next-generation energy storage systems. [ABSTRACT FROM AUTHOR]

Lithium iron silicate (Li 2 FeSiO 4) has high theoretical capacity of 332 mAh∙g-1 upon full extraction of two lithium ions, which is accompanied by high delithiation potential and large volume change. Sulfur modification could be an effective approach for stabilizing Li 2 FeSiO 4 cathodes. A series of carbon-coated Li 2 FeSiO 4 samples were prepared through a hydrothermal and solid-state reaction route at a fixed sucrose content (14 wt% carbon) with varying amounts of sublimed sulfur at 5, 10, 15, 20 and 25 at%. The crystal structures, chemical compositions, microstructures and electrochemical performances of the differently sulfur-modified Li 2 FeSiO 4 /C were systematically investigated. The sulfur-carbon co-modifications and possible existing chemical states of sulfur are discussed in terms of the surface and near-bulk modifications. It was found that all the samples exhibited a monoclinic P 2 1 structural Li 2 FeSiO 4 , while the sulfur contents over 10 at% formed impure phases such as iron sulfides (Fe 1-x S) and lithium metasilicate (Li 2 SiO 3). Furthermore, three types of sulfur states could be found when sulfur and carbon were added simultaneously into Li 2 FeSiO 4. The surfaces were predominated by S–C and S–O–C, indicating the sulfur-carbon co-modification, which would reduce the resistance at the solid/electrode interface (SEI) but increase the charge transfer resistance. Near the bulk, the enhanced interactions between sulfur and iron S–Fe(−S) or sulfur and silicon S–Si(−O) may lead to the formation of possible impurities or oxygen substitution by sulfur. The former is detrimental as the effective sulfur amount is reduced, while the latter is beneficial to improve specific capacity and cycle stability. The overall performance of sulfur-carbon co-modified sample is influenced complicatedly by the sulfur content. The best initial discharge capacity of 152.3 mAh∙g-1 was obtained with 5 at% sulfur modification, while the best overall performance, showing a typical warm-up response and good cycle stability, was observed with 15 at% sulfur modification. [ABSTRACT FROM AUTHOR]

As a typical transition-metal dichalcogenide (TMD), vanadium disulfide (VS 2) is an excellent candidate for cathode material in lithium-ion batteries due to its metallic properties and large interlayer spacing. But they often suffer from low intercalation capacity and sluggish kinetics processes, significantly limiting their practical application. Herein, the cetyltrimethylammonium bromide (CTAB) is employed in the synthesis process to construct the sulfur (S) vacancy in VS 2. The sulfur vacancy could improve its intercalation capacity and kinetics performance. In this structure, the interlayer vacancy defects could provide extra intercalation sites to improve intercalation capacity. It could induce multiple migration paths for lithium-ion (Li+) and electron (e–), enabling fast Li + migration and rapid charge transfer. It also presents favorable rate performance with a high pseudocapacitance contribution during a typical intercalation reaction. The above positive behaviors significantly promote the kinetics performance of VS 2-x as a cathode material for lithium-ion batteries (smaller charge transfer resistance and high Li+ diffusion rate). Finally, this material could provide a high storage capacity of 140 mAh g−1 after 180th and favorable rate performance (55.5 mAh g−1 at 1A g−1). This work could provide a reference for improving TMD's electrochemical performance and expanding their applications. [ABSTRACT FROM AUTHOR]

A nanostructured Ni-ferrite material, NiFe 2 O 4 , was successfully synthesized via facile co-precipitation in hot water, followed by an annealing process. The developed Ni-ferrite was face-centered cubic, highly crystalline, and nano-sized. The Ni-ferrite anode revealed superior electrochemical properties for Li-ion batteries, such as high reversible capacity and long cyclability, without significant capacity fading. Specifically, this anode exhibited reversible capacities of 926 and 1586 mAh g−1 at the 1st and 150th cycles at 0.1 A g−1, respectively. The superior electrochemical performance was attributed to the size and unique properties of the Ni-ferrite spinel. Nano-sized materials were beneficial for creating a large contact area between the electrode and electrolyte, increasing diffusion rates of lithium ions, resulting in enhanced pseudo-behavior. The properties of spinel structure and the presence of Fe and Ni metals during charge/discharge in Ni-ferrite prevented the destruction of the anode and catalyzed the decomposition of the Li 2 O phase, leading to extraordinary highly-reversible Li storage. [Display omitted] • Spinel Ni-ferrite is prepared via a simple coprecipitation route. • Spinel Ni-ferrite possesses nanostructures (from 20 to 65 nm) with high crystallinity. • Detailed pseudo and diffusive behaviors of Ni-ferrite electrode are investigated via mathematic method. • Spinel Ni-ferrite demonstrates a high reversible capacity (∼1586 mAh g−1 at 150 cycles). [ABSTRACT FROM AUTHOR]

Polyethylene(PE) diaphragm has become broadly used in lithium-ion battery systems because of its high strength, exceptional plasticity, and resistance to organic solvents. Nevertheless, the lack of polar groups on the surface of the PE diaphragms has a little significant effect on the ionic polarity of the electrolyte. Consequently, the electrolyte has poor wettability, the lithium-ion migration number t Li + (0.21) and the ion conductivity σ (0.63 mS/cm) still need to be further improved, which restricts its application to a certain extent. In this work, the high-purity zinc borate modified PE diaphragms with Lewis acid sites were prepared via a simple solid-state method. The multifunctional diaphragms modified by zinc borate have the following advantages: (1) The Zn–O bond and -BO 3 group in the structure have a polar bond and Lewis acid action, respectively, which can promote the desolvation of lithium ions and the dissociation of anions and cations, thereby increasing the concentration of free ions. In addition, zinc borate and anions have a specific binding effect, which can inhibit the migration of anions, consequently increasing t Li + (0.41) and σ (1.14 mS/cm); (2) Zinc borate was a commonly used flame retardant, which was conducive to improving the thermal stability of the PE diaphragms; (3) The surface of the modified diaphragms is rougher, which can increase the specific surface area of the diaphragm, hence enhancing its liquid absorption capacity. The electrochemical performance test results show that the modification of zinc borate can effectively improve the comprehensive performance of the PE diaphragm and the overall cycle stability and rate performance of the lithium iron phosphate battery. [ABSTRACT FROM AUTHOR]

Layered high-nickel LiNi 0.8 Co 0.1 Mn 0.1 O 2 is a promising candidate of the next generation cathode materials for lithium-ion batteries. However, severe cycling instability and fast capacity drop induced by anisotropic structured change restrict its wide application. To address these defects, the structure design of cathodes is conducted. Herein, a hierarchical layered LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode consisting of orderly stacking hexagonal nanosheets with exposed active {104} facets is successfully synthesized by an improved co-precipitation process and followed with a high temperature lithiation reaction. Benefiting from this unique texture, exposed active {104} facets with lower surface energy supply 3D barrier-free Li+ ion diffusion channels, significantly improving the efficiency of the Li+ diffusion. Moreover, the consistent arrangement of nanosheets in the manner of the {001} facets close attachment is beneficial to alleviate the stress caused by the anisotropic structured change. Thus, this cathode material presents both superior reversible capability (203.8 mAh g−1 at 0.1C, 184.5 mAh g−1 at 1 C, 173.0 mAh g−1 at 5 C and 161.3 mAh g−1 at 10 C) and stable cycling performance (capacity retention of 89.3% after 100 cycles at 1 C, 55.3% after 300 cycles at 5 C and 59.6% after 300 cycles at 10 C). Schematic of single crystal shape evolution of the cathode materials and the corresponding cycle performance of the NCM-3 sample at different rates. [Display omitted] • A hierarchical cathode material consisting of orderly stacking nanosheets with exposed active {104} facets was successfully synthesized. • The exposed active {104} facets with lower surface energy could supply barrier-free Li+ ion diffusion channels. • The consistent arrangement of nanosheets is beneficial to alleviate the stress and inhibit the pulverization of secondary particles. • The hierarchical cathode material presents both superior reversible capability and stable cycling performance. [ABSTRACT FROM AUTHOR]

A cohesive architecture of 1T-MoS 2 covered by PPy composite (1T-MoS 2 @PPy) is successfully fabricated by a simple hydrothermal reaction followed by an in-situ polymerization route. The composite material consists of 1T-MoS 2 hollow microsphere and conductive PPy coating layer. The cohesive architecture enables the composite to show rapid shuttle of electrons/lithium ions and good ductility to buffer the volume changes during charging and discharging process when it is used as anode material. As expected, 1T-MoS 2 @PPy composite exhibits a favorable discharge capacity up to 970.3 and 407.1 mAh g−1 at 0.2 and 3 A g−1, respectively. In addition, the composite also achieves impressive cycling performance of 717.1 mAh g−1 at 1 A g-1 after 500 cycles. This study provides a meaningful guidance in rational design of anode materials with cohesive architecture as well as high electrochemical performance. [ABSTRACT FROM AUTHOR]

A novel negative material consisting of graphene nanotubes and ultrathin MoS 2 is synthesized by a simple one-step hydrothermal method assisted with Sodium chloride. The MoS 2 /Graphene electrodes deliver a specific capacity of 1350 mAh g−1 under 0.1 A g−1 and high rate capability (retaining 85.5% capacity from 0.1 A g−1 to 0.8 A g−1). A high remarkable capacity of 820 mAh g−1 can still be recovered at 0.5 A g−1 after 500 cycles, and the average coulombic efficiency was as high as 99.98% during the additional 500 cycles. The excellent Li-ion storage performance of MoS 2 /Graphene nanotubes may be attributed to the ultra-thin MoS 2 flakes and curled graphene nanotubes. This structural feature has a strong adsorption capacity for lithium ions, which can provide a broad space for ion storage. A large number of active sites dispersed in the layered molybdenum disulfide promote the kinetics of the electrochemical reaction, empowering the ultra-thin layered molybdenum disulfide to get a higher theoretical capacity. In addition, the existence of the tubular structure alleviates volume expansion and provides a way for the rapid movement of electrons and diffusion of Li+ during repeated cycles. [ABSTRACT FROM AUTHOR]

This work reports on the structural, electrical and electrochemical properties of Zn doped LiNi 0.5-x Zn x Mn 1.5 O 4 (x = 0.0, 0.05, 0.1 and 0.2) porous microspheres cathode materials obtained by a hydrothermal route followed by low-temperature annealing. Structural properties are investigated by X-ray diffraction (XRD), nuclear magnetic resonance (NMR) spectroscopy; scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman, and Fourier transform infrared (FTIR) spectroscopy. The XRD patterns and NMR studies further demonstrate the successful incorporation of Zn into the spinel structure. SEM reveals morphology with porous spheres with a size range of 0.2 μm – 1 μm. Temperature dependent electrical conductivity was measured by impedance spectroscopy. The activation energies of total conductivity are determined as 0.41, 0.41, 0.47, and 0.48 eV for x = 0, 0.05, 0.1, and 0.2, respectively. Influence of Zn doping on the grain, grain boundary and total conductivities of LiNi 0.5-x Zn x Mn 1.5 O 4 were analyzed through brick-layer model. The grain conductivity increases with Zn content, whereas the total conductivity increases till x = 0.1. Overall, electrical properties of LiNi 0.5-x Zn x Mn 1.5 O 4 are governed by grain boundary conduction. Increasing the Zn content up to x = 0.1 in LiNi 0.5-x Zn x Mn 1.5 O 4 leads to an increment in specific capacity at a 1C rate. Among them, the LiNi 0.4 Zn 0.1 Mn 1.5 O 4 exhibits a high discharge capacity of 114 mAh g−1 at 1C with capacity retention of 91.5% after 50 cycles. We also investigated the effect of Zn doping on Li+ ion diffusivity and observed improved Li+ ion diffusion (7.4⋅10−13 cm2 s−1) for LiNi 0.4 Zn 0.1 Mn 1.5 O 4. Based on these electrochemical studies it is proposed that this material can be utilized as a cathode in Li-ion batteries for high-power applications. [ABSTRACT FROM AUTHOR]

LiNi 0.5 Mn 1.5 O 4 (LNMO) is a promising next-generation cathode material for high energy density lithium-ion batteries, but the application of LNMO is blocked because of its inherent side effects with electrolytes at high voltages, namely, serious Mn dissolution and capacity attenuation. A novel LiNi 0.5 Mn 1.5-x Sr x O 4 material (x = 0, 0.05, 0.1, 0.15, and 0.2) was successfully prepared using the sol-gel method, and the effect of varying in situ Sr2+-doping on the crystal structure, morphology, and electrochemical performance was researched. A series of characterizations showed that the Sr-doped LNMO structure contains less Mn3+, which enhances its cycling stability. In addition, Sr doping promotes morphological changes more remarkably. Accompanied by the appearance of (100) surfaces, the morphology of LNMO changes from an octahedron to a truncated octahedron. The (100) surface can effectively inhibit side reactions with the electrolyte and steady the structure at the working voltage, which also helps support Li+ transport kinetics. The Sr-doped LiNi 0.5 Mn 1.4 Sr 0.1 O 4 (expressed as LNMO-Sr0.1) cathode exhibits preeminent cycling stability, after 500 cycles at 1C, the capacity retention is 86.63 %. CV and EIS results show that the right amount of Sr doping efficiently reduces electrode polarization and charge transfer resistance and increases the Li+ diffusion coefficient. [Display omitted] [ABSTRACT FROM AUTHOR]

The metal selenides/tellurides have attracted considerable concerns for high-capacity lithium ion batteries (LiBs) because of their high conductivity, low voltage polarization and high theoretical coulombic efficiency. However, poor cyclability is still a big challenge that impedes their practical applications. Herein, GeSe2/Carbon (GeSe2/C) composite was fabricated by solid-state reaction method and its lithium ion (Li+) storage performances were investigated using flexible polyacrylonitrile (PAN) gel polymer electrolyte as separator. Reversible capacity of the GeSe2/C|PAN|Li system was ~20% higher than that of the GeSe2/C|polypropylene (PP)|Li system. Upon NaCl-assisted ball milling process, SEM and TEM observations revealed that the size of GeSe2/C particles significantly decreased from 30 μm to 100–500 nm. The milled GeSe2/C displayed a high capacity of 623.6 mA h g−1 at 350th cycle, which was 90.7% of the 2nd discharge capacity value, and the reversible capacity showed a 1100% improvement by using PAN as separator compared to the conventional PP separator. This study might inspire manufacturing of high-performance LiBs for energy storage. [Display omitted] [ABSTRACT FROM AUTHOR]

Graphite nanosheets coated by LiF/SnO 2 composites are designed to obtain a lithium ion anode material with excellent performance. LiF nanoparticles play a significant role in improving the electrochemical performance by inhibiting electrolyte decomposition and providing excess Li sources during cycling. The obtained LiF@SnO 2 @C electrode shows an outstanding capacity of 951.9 mAhg−1 at 0.2 Ag-1 after 370 cycles and excellent long cycling performance of 650.0 mAhg−1 at 1.0 Ag-1 after 930 cycles. First-principles calculations demonstrate that F-doped SnO 2 (−2211.8 eV) has a lower free energy compared to SnO 2 (−1937.4 eV), resulting in a robust composite architecture that gives rise to high cycling stability. [ABSTRACT FROM AUTHOR]

Li 2 ZnTi 3 O 8 @ α -Fe 2 O 3 composites have been successfully prepared by a facile hydrothermal process. Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composites show similar irregular spherical morphologies like Li 2 ZnTi 3 O 8 and relatively smaller particle sizes than pristine Li 2 ZnTi 3 O 8. Among all Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composites, Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composite (5 wt%) exhibits the best electrochemical properties. Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composite (5 wt%) delivers a reversible charge capacity of 184.8 mAh g−1 even at 1000 mA g−1 after 500 cycles, while pristine Li 2 ZnTi 3 O 8 only delivers a reversible charge capacity of 110.7 mAh g−1. The strong covalent bonds between Li 2 ZnTi 3 O 8 and α-Fe 2 O 3 will be formed, which is beneficial for the reduction of interfacial energy and thus helpful for the stabilization of the composite. Because of the special synergistic effect of the multi-phase interface, Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composites not only possess the advantages of single components but also show novel and attractive performances, such as the enhanced ionic conductivity, reduced interfacial charge transfer impedance, improved migration rate of lithium ions, and the enhancement of the rate performance and reversible capacity. The as-prepared Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composites reveal important potentials as anode materials for next-generation rechargeable Li-ion batteries, and this work also offers an effective strategy to design high performance lithium storage materials for advanced lithium-ion batteries. [ABSTRACT FROM AUTHOR]

TiO 2 is exceptionally useful anode material for Li-ion batteries, and the ability to modify TiO 2 makes it a very attractive and challenging research object for use in different functional materials. In this paper, mesoporous TiO 2 nano hollow spheres (dubbed TiO 2 -1 andTiO 2 -2) with moderate oxygen vacancies were successfully prepared. Structure and composition characterizations revealed that the spheres had a hollow structure, surface oxygen vacancies and an excellent Ti3+/Ti4+ molar ratio of 0.181. In addition, TiO 2 -2 demonstrated synergistic effects in terms of electron and lithium ion transportation, with impedances as low as 3.05 Ω, and its Li-ion diffusion coefficient (7.8 × 10−12 cm2 s−1) was at least a factor of 10 larger than that of TiO 2 -1(6.2 × 10−13 cm2 s−1). More importantly, experiments demonstrated that the well-balanced Li+/e− transportation arising from the synergetic effect between structure and Ti3+/oxygen vacancy in the optimal TiO 2 -2 sample had a high specific capacity of 233 mAh·g−1 at 0.1C, and 79.8% capacity retention after 100 cycles, as well as greatly enhanced rate performance and electrochemical reactivity and stability in comparison with the other TiO 2. Our method for creating oxygen vacancies in TiO 2 nano hollow spheres can be generalized to other electrochemical energy storage materials. [ABSTRACT FROM AUTHOR]

In the present work, submicrometer CoMoO 4 is successfully prepared by a facile polymer-pyrolysis method. The phase, structure, composition and morphology of the obtained sample are characterized by several techniques. The proper reaction temperature is 600 °C. As an anode material of lithium half-battery, the sample prepared at 600 °C exhibits a stable reversible capacity of 667.6 mAh g−1 at a current density of 0.2 A g−1. A 96.7% capacity retention is observed between 10 and 100 cycles, where lithium storage reaction is dominated by ionic diffusion, and the diffusion coefficient of lithium ion is about 0.12 × 10−15 cm2 s−1. As electrode of supercapacitors, a high specific capacitance of around 304.6 F g−1 is achieved at a current density of 0.5 A g−1 after 1000 cycles. Therefore, the polymer-pyrolysis method shows great promise in preparing the CoMoO 4. [ABSTRACT FROM AUTHOR]

To synthesize and optimize stoichiometric Li(Ni 0. 84 Co 0.16) 1-x Al x O 2 (NCA, 0 < x < 0.1) cathode materials with enhanced structural stability, different contents of nano Al(OH) 3 powders are employed to co -calcine with home-made Ni 0. 84 Co 0. 16 (OH) 2 precursor and LiOH·H 2 O by ball milling and followed by being co -calcined at 750 °C for 15 h. The results characterized by energy dispersive spectrometer, X-ray diffraction, and transmission electron microscope demonstrate that the as-prepared stoichiometric LiNi 0. 81 Co 0. 15 Al 0. 04 O 2 (NC-A4) sample presents a slightly decreasing Al atom concentration from the surface to the core, a lowering cationic disorder degree of 1.69% and an enlarged interplanar distance of the (003) phase of 0.482 nm when the content of the doped nano Al(OH) 3 powders is up to 4% based on the precursor. Moreover, the coin cell assembled with NC-A4 can deliver an initial discharge specific capacity of 196.3 mAh g−1 and retain 170.7 mAh g−1 after 100 cycles at 1.0 C at 30 °C with a remarkable capacity retention of 95.5%. Even though at a high current density of 5.0 C , it can also present a superior rate capacity of 162.1 mAh g−1. The enhanced electrochemical performance of NC-A4 is primarily attributed to the significant improvement in the structural stability with trivalent Al ions doping, which can not only maintain a stable lattice structure during the lithiation/delithiation process, but also alleviate the increasement of polarization degree and R ct value. Hence, the presented method would be a simple and effective way to construct stoichiometric and high-performance NCA cathode materials with excellent structural stability for lithium ions batteries. [ABSTRACT FROM AUTHOR]

In this study, La was doped into the lithium layer of Li-rich cathode material and formed a layered-spinel hetero-structure. The morphology, crystal structure, element valence and kinetics of lithium ion migration were studied by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The La doped lithium-rich cathode material exhibited similar initial discharge capacity of 262.8 mAh g−1 at 0.1 C compared with the undoped material, but the discharge capacity retention rate can be obviously improved to 90% after 50 cycles at 1.0 C. Besides that, much better rate capability and Li+ diffusion coefficient were observed. The results revealed that La doping not only stabilized the material structure and reduced the Li/Ni mixing degree, but also induced the generation of spinel phase to provide three-dimensional diffusion channels for lithium ion migration. Moreover, the porous structure of the doped samples also contributed to the remarkable excellent electrochemical performance. All of these factors combined to significantly improve the electrochemical performance of the material. [ABSTRACT FROM AUTHOR]

Poor electrical conductivity and large volume changes are two disadvantages of metal selenides. In this work, MnSe nanoparticles encapsulated into N-carbon fibers are designed and prepared using electrospinning and calcination methods. When calcined at 700 °C, the composite has a high reversible capacity of 684 mAh g−1 after 100 cycles at 0.1 A g−1, owing to the improved conductivity and protection provided by carbon fibers. Furthermore, the in situ electrochemical impedance measurements reveal the process kinetics of the composites. This work will provide the basis for the further development of the application of metal selenides in the field of flexible electrodes. [ABSTRACT FROM AUTHOR]

Silicon monoxide (SiO x , 0 < x < 2) is considered to be one of the most promising anode materials, due to its higher theoretical specific capacity relative to graphite and smaller volume expansion rate relative to silicon materials. However, SiO x anode material still has its own disadvantages such as poor conductivity. In view of this situation, the SiO x /Ag/C composite material was synthesized with self-selective electroless deposition and carbon-coated technology by using ball-milled SiO x. Through the synergistic effect of Ag nanoparticles and the carbon layer, the electronic conductivity and the lithium ion diffusion coefficient of the SiO x /Ag/C composite was improved and its volume expansion was inhibited. Thus the SiO x /Ag/C composite of layered structure holds an excellent cycling performance with the discharge specific capacity of 1102.7 mAh·g-1 after 150 cycles at current density of 0.5C (1C = 2.1 A g-1), which is 345.1 mAh·g-1 higher than the discharge capacity of SiO x /C, and the SiO x /Ag/C composite shows 403.2 mAh·g-1 higher capacity than that of as-ball-milled SiO x at 2 C by rate performance test. [ABSTRACT FROM AUTHOR]

The separator is used to isolate the cathode and anode material, playing an important role in the safety of battery, which prevents internal short circuit of battery and provides lithium ions free flow channels. In this paper, based on the commercial ceramic-coated polyethylene (PE) separator (CPES), low-melting point PE microspheres were mixed in ceramic-coating to form the functionalized PE separator (FPES) for improving the safety tolerance of large scale lithium-ion batteries (LIBs). Compared to the CPES shutdown temperature of ~135 °C, the shutdown temperature of FPES significantly decreased to ~110 °C. Compared with 27 Ah pouch battery assembled by CPES, the FPES can effectively improve the tolerance of overcharge and internal short circuit without sacrificing the electrochemical performance. In addition, a novel internal short circuit of FPES protection mechanism model was proposed. Molten PE microspheres of FPES would flow along the edge of broken hole, reducing the contact probability between the cathode and anode, and ultimately increasing the resistance of internal short circuit by 41% compared to CPES. Therefore, the obtained results provide important implications for the development of safer separator and LIBs. [ABSTRACT FROM AUTHOR]

Novel structured porous hollow six-branched star-like MnO was synthesized via a facile, surfactant-free hydrothermal decomposition, which was followed by high-temperature heat treatment. Compared with the nonporous hollow six-branched star-like MnO 2 , the porous hollow six-branched star-like MnO realized substantially higher electrochemical performance (844.8 mAh g−1 at 0.5 A g−1 after 200 cycles and 769.7, 741.7, 728.9, 713.2, and 704.4 mAh g−1 at 0.1, 0.3, 0.5, 1, and 1.5 A g−1, respectively, for porous star-like MnO, compared with 338.4 mAh g−1 and 476.7, 392.4, 357, 303.4, and 269.9, respectively, under the same testing conditions for nonporous star-like MnO 2). The superior performance of the porous hollow six-branched star-like MnO is attributed to its enhanced electrode kinetics, which are due to an enlarged active contact area and shortened electron and Li+ conduction paths. [ABSTRACT FROM AUTHOR]

To optimize the performance of LiNiO 2 with minimal modification of the pristine structure, a facile solid-state approach, based on the interdiffusion of elements at the solid/solid interface, is developed to achieve uniformly Al-doped LiNiO 2 using alumina coated Ni(OH) 2 spheres as the precursor. The resulting LiNi 0.95 Al 0.05 O 2 material exhibits excellent discharge capacity (209.9 mAh g−1 at 0.1 C) and cycling stability with a capacity retention of 85.10% after 200 cycles at 0.5 C. This is ascribed to the improved reversibility of the phase transitions by Al-doping as revealed by in-situ XRD characterization. The Al-doping also endows the material with superior rate capability due to the enlarged interlayer spacing in the structure and alleviation of the side reactions at the electrode/electrolyte interface, favorable for lithium ion diffusion. An optimal amount of doped Al is necessary for ensuring the structure stability and interface ionic conductivity of the LiNiO 2 spheres. Thus, the present strategy may provide an opportunity to optimize the performance of LiNiO 2 , with uniform doping of a small amount of Al, producing a promising cathode material for advanced lithium ion batteries. [ABSTRACT FROM AUTHOR]

A truncated octahedron LiNi 0.10 Mn 1.90 O 4 cathode material with (111), (100) and (110) crystal plane was easily synthesized by a solid-state combustion approach under heat treatment at 500 °C for 1 h and then 700 °C for 6 h. The as-prepared LiNi 0.10 Mn 1.90 O 4 presents a particle distribution of approximately 200 nm and well maintains the characteristic spinel structure with no any impurities. Benefiting from the truncated octahedron morphology and Ni doping, lithium ions diffusion capability is enhanced and rebarbative Jahn-Teller distortion is also inhibited. Consequently, the LiNi 0.10 Mn 1.90 O 4 cathode retains a superior capacity retention of 75.1% after 1000 cycles at 5 C, the corresponding LiMn 2 O 4 is only 44.08%. Even at a high current rate of 10 C, the LiNi 0.10 Mn 1.90 O 4 delivers an initial capacity of 87.1 mAh/g and can undergo ultralong 2500 cycles. [ABSTRACT FROM AUTHOR]

The refractory lining in a furnace is always damaged and peels off when spent lithium-ion secondary batteries (LIB) are pyro-processed in a rotary kiln. To develop highly durable refractories and to elucidate the erosion behavior, various analyses such as scanning electron microscopy/energy dispersive X-ray spectroscopy, laser-induced breakdown spectroscopy, inductively coupled plasma atomic emission spectroscopy, ion chromatography, and X-ray diffraction were performed on the linings sampled from different sections of a refractory. Our results suggested the following mechanisms in Al 2 O 3 –SiO 2 –CaO refractory damage during pyro-processing of spent LIB packs. First, Li 2 O, P 2 O 5 , LiF, and HF were formed by thermal decomposition of electrolyte constituents of the lithium-ion secondary batteries. When HF reacts with SiO 2 , Al 2 O 3 , and CaO on the surface of the refractory, each fluoride that forms vaporizes and melts. When Li 2 O and P 2 O 5 (as well as LiF) react with the Al 2 O 3 –SiO 2 refractory, an Li 2 O–Al 2 O 3 –SiO 2 –P 2 O 5 (-LiF) phase with a low melting point forms and penetrates into the refractory through pores, grain boundaries, and cracks, resulting in peeling off. [ABSTRACT FROM AUTHOR]

A porous carbon nanocomposite with embedded TiO 2 nanowires (NWs) was synthesized using a two-step synthetic method in which carbon matrix was obtained by carbonizing a vacuum dried gel. This unique structure in which TiO 2 nanowires uniformly distributed in and tightly bonded to the carbon matrix shortened the electron transport path and reduced the transmission resistance. Nanoporous structure ensured continuous transfer of Li+/Na+ and supplied a large specific surface area of 280.82 m2 g−1 to provide more active sites. Different from other existing works on TiO 2 @C anode materials with TiO 2 loading higher than 60 wt%, the obtained very small amount of TiO 2 (~12 wt%) improved the electrochemical and long-cycle performance of carbon substrate with TiO 2 NWs embedded significantly, due to uniformly distributed TiO 2 NWs throughout the carbon matrix. These TiO 2 @C composite anodes could deliver a specific capacity of 286 mA h g−1 at 0.3 C, 197 mA h g−1 at 0.15 C for lithium and sodium ion batteries, respectively. It maintained remarkably stable reversible capacities of 128 and 125 mA h g−1 for lithium and sodium ion batteries at 3 C during 2500 cycles, respectively. Smaller fluctuations and smoother curves demonstrated that sodium ion storage was more stable than lithium ion storage for the TiO 2 @C composite anode. In addition, the capacitive contributions of TiO 2 @C in both systems are quantified by kinetics analysis. [ABSTRACT FROM AUTHOR]

The improvement in electrode materials to upgrade lithium ion battery (LIB) is at heart of research related to energy devices. Herein, we report on the prospects of using 2H–SiC as an anode material in LIB on the basis of first principles based theoretical predictions. The energy profiling of high symmetry structural sites pointed out that the site T C related to tetrahedral configuration with carbon is favorable intercalation site in the host. The reaction of Li with stoichiometric as well as non-stoichiometric 2H–SiC are found endothermic which points to their unsuitability for lithiation process in LIBs. However, Li intercalation into the host in presence of Si monovacancy appeared an exothermic process which motivated us to study this system in detail. The Li atom after intercalation into the host is found ionized thereby donating its 2s electron to carbon atoms. The average value of the lithium insertion voltage and theoretical capacity are calculated as 1.87 V and 85 mA h/g respectively for the host simulated in the form of supercell Li x Si 15 C 16. The diffusion barrier faced by lithium atom while moving along crystalline a-axis is minimum (among all the paths considered here) when it follows a path that links hexagonal rings while passing carbon atoms. On the other hand, in case of motion along c-axis, similar results are found for minimum energy path that is along Tc site. The low diffusion barrier will facilitate the lithium ion to move quickly that points to fast charging capability of the battery. [ABSTRACT FROM AUTHOR]

Nd:BiVO 4 nanocrystals were synthesized by an effective and simple approach. Nd was incorporated into BiVO 4 host to enhance electronic conductivity and lithium-ion diffusion kinetics, thus promoting the electrochemical performance. When employed as anode materials in lithium-ion batteries, a good cycling stability and high capacity of ~611 mAh g−1 at 100 mA g−1 were delivered. The work can be extensively employed for fabricating other electrode materials and promoting the electrochemical performance in energy storage correlative domains. [ABSTRACT FROM AUTHOR]

Aqueous lithium ion batteries show bright foreground in energy storage and electronic products. However, the performance of anode needs to be further improved to meet their higher requirements. Herein, we endowed LiTi 2 (PO 4) 3 /C with excellent electrochemical performance through rational Br doping on PO 4 3− sites. A series of Br doped LiTi 2 (PO 4) 3-x Br x /C (x = 0.00, 0.12, 0.18, and 0.24) samples were obtained via sol-gel means associated with heat-treatment, which were employed as anodes for aqueous lithium ion batteries. There are no notable impacts on morphology and lattice structure of LiTi 2 (PO 4) 3 with Br doping. And electrochemical capabilities of LiTi 2 (PO 4) 3 are evidently ameliorated by Br doping contrasted to original LiTi 2 (PO 4) 3 /C (LC). LiTi 2 (PO 4) 2.82 Br 0.18 /C demonstrates superb electrochemical property with the discharge capacities of 132.3, 112.3, and 86.3 mAh g−1 at 0.5, 7, and 15 C, separately, 27.3, 32.7, and 34.3 mAh g−1 higher than these of original LC. This may be due to that Br doping widens pathway for Li ions and improves intrinsic electronic conductivity of sample, accelerating ion and electron migration. The work shows that Br doping is a valid approach to ameliorate LiTi 2 (PO 4) 3 /C performance for aqueous lithium ion batteries. [ABSTRACT FROM AUTHOR]

Herein, porous NiMoO 4 @C nanowire is purposefully synthesized using oleic acid as carbon source, and further evaluated as high performance anode material for Li-ion batteries (LIBs). Compared with the pure NiMoO 4 , porous NiMoO 4 @C nanowire exhibits high reversible charge/discharge specific capacity, excellent cycle stability and preeminent rate capability. A stable reversible lithium storage capacity of 975 mAh g−1 can still be maintained after 100 cycles at 200 mA g−1. When the current density decreases back from 3000 mA g−1 to 100 mA g−1, a high discharge specific capacity of 884 mAh g−1 is recovered. The porous structure and carbon layers can enhance the electronic transmission and structural stability, shorten the path lengths for ion and electron transport, and provide a mechanical buffer space to accommodate the volume expansion/contraction during the repeated Li+ insertion/extraction processes. All the results highlight that the porous NiMoO 4 @C nanowire composite would be a promising candidate for high performance anode material of LIBs owing to its excellent electrochemical properties. [ABSTRACT FROM AUTHOR]

High working potential and temperature put nonnegligible threats on electrochemical stability and safety performance of lithium ion batteries (LIBs). In this paper the carbonate-based electrolyte is modified with LiF additive to improve the comprehensive properties of cells in which a metallic lithium anode is paired with a LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622) cathode under the extreme conditions of high cut-off potential, high current rate or even high temperature (55 °C). The tests of self-discharge behavior and chronoamperometry present that the introduction of LiF additive contributes to relieving self-discharge of cells and side reactions on the surface of electrodes. The cells with 100 ppm exhibit the improved cyclic performance (81.6% of initial capacity 195.4 mAh g−1), high-rate capability (150.6 mAh g−1 at 8 C) and high-temperature performance. Additionally after 100 cycles over 3.0–4.6 V, the results of X-ray diffraction (XRD) and scanning electron microscopy (SEM) on electrodes reveal that the cathodes in LiF-reinforced electrolyte retain more stable layered structure and more intact spherical secondary particles than those in original electrolyte. [ABSTRACT FROM AUTHOR]

A hollow tremella-like graphene sphere/tin dioxide (HTGS/SnO 2) composite was successfully prepared by simple emulsification and impregnation followed by calcination. In this material, tin dioxide adheres to the folds on the surface of the hollow tremella-like graphene spheres. Hollow tremella-like graphene spheres as the matrix of SnO 2 not only provide a space of volumetric expansion for the tin oxide particles, relieve the internal stress of the tin dioxide, but also effectively avoid aggregation of the tin dioxide and increase the electrical conductivity. As an anode electrode material for batteries, the initial discharge/charge capacities of HTGS/SnO 2 are 1762.4 mAh g-1 and 1169.4 mAh g-1, and the Coulomb efficiency is 96.9%. After 50 cycles, capacity remains 80.4% of reversible capacity. The excellent electrochemical stability is attributed to the extraordinary structure of HTGS/SnO 2. The hollow structure of graphene sphere allows simultaneous insertion of lithium ions from the inner and outer surfaces. Meanwhile, the tin dioxide particles are uniformly dispersed by the wrinkles on the surface of the graphene, thereby enlarging the space for the volume expansion of tin dioxide in order to avoid contact with the electrolyte. [ABSTRACT FROM AUTHOR]

A novel sphere-like SnO 2 /TiO 2 composite is synthesized via spray-drying followed by calcination as confirmed by X-ray diffraction and field emission-scanning electron microscopy analyses; the SnO 2 /TiO 2 composite is composed of the tetragonal cassiterite-like SnO 2 nanoparticles and anatase-like TiO 2 nanospheres. The characterization results show that the optimal stoichiometric ratio of SnO 2 /TiO 2 is approximately 3:1 when the composite serves as the anode for lithium ion batteries, in which the composite electrode not only delivers a high initial discharge specific capacity of 1476 mAh g−1 and retains 483 mAh g−1 after 40 cycles at 500 mA g−1 but also presents a low transfer resistance of approximately 56.33 Ω, a high Warburg coefficient of up to 85.82 Ω cm2 s−0.5, and a high lithium ion diffusion coefficient of approximately 6.934 E-15 cm2 s−1 at ambient temperature. These excellent electrochemical properties suggest that the SnO 2 /TiO 2 composite electrode may be a promising anode material for lithium ion batteries. [ABSTRACT FROM AUTHOR]

The hollow TiO 2 @rGO hybrid spheres are in-situ synthesized by using TiO 2 spheres as a precursor and a simple hydrothermal route with subsequent annealing. The unique hollow structure has large special surface areas, and the reduced graphene oxide (rGO) layer can accelerate transfer of lithium ions and electrons and efficiently enhance the structural stability. The prepared hollow TiO 2 @rGO hybrid spheres exhibit better electrochemical performance than pure TiO 2 hollow microspheres. It exhibits a high special capacity of 254.3 mA h g−1 at 1C after 600 cycles and highly stable capacity retention, and superior rate capacity of 159.1 mAh g−1 at 10C after 3000 cycles. Moreover, the hollow TiO 2 @rGO hybrid spheres have high surface area, superior structural stability, and excellent high-rate and long-life cycle property as anode material for LIBs. [ABSTRACT FROM AUTHOR]

Here, LiY(WO 4) 2 nanotubes are prepared via a feasible electrospinning technique. This new anode material shows excellent electrochemical properties. The capacity loss of LiY(WO 4) 2 nanotubes is as low as 6.9% after 156 cycles, while bulk LiY(WO 4) 2 presents the capacity loss higher than 55.0%. Even after 600 long-life cycles, the capacity loss of the nanotubes is only 9%. It can be seen that the hollow structure with a rough surface and a porous morphology contributes to the improvement of electrochemical performance. Furthermore, online X-ray diffraction (XRD) method is firstly applied to understand the lithium ions insertion/extraction mechanism of LiY(WO 4) 2 nanotubes. It can be concluded that it is an asymmetrical two-phase reaction. A phase transformation from LiY(WO 4) 2 to Li 3 Y(WO 4) 2 can be obviously seen from the in situ XRD during discharge process. While Li 2 Y(WO 4) 2 appears as an intermediate phase with a reverse charge reaction. In addition, in situ XRD also demonstrates that LiY(WO 4) 2 nanotubes have surprised electrochemical reversibility. All the above results indicate that LiY(WO 4) 2 nanotubes can be expected to be anode candidate for rechargeable lithium ion batteries (LIBs). [ABSTRACT FROM AUTHOR]

Abstract Na+ and Fe2+ were co-doped at the Li and Mn site of LiMnPO 4 /C through a simple solvothermal method. Researches show that Li 1-x Na x Mn 0.8 Fe 0.2 PO 4 /C nanocapsule is generated through the self-assembly without surfactant. The simultaneous successfully doping of Na+ and Fe2+, which is proved by the EDS and XPS of Li 0.97 Na 0.03 Mn 0.8 Fe 0.2 PO 4 /C (LN-3), does not cause the rearrangement of cation. The particle sizes of nanocapsule decrease gradually with the doping of Na+. The pyrolytic carbon with excellent conductivity is coated on the surface of nanocapsule. The crystal of LN-3 nanocapsule with regular diffraction lattice is well developed. The doping of Na+ does not change the potential of electrochemical reaction. Cathode LN-3 delivers the maximum electrochemical performance. Its specific capacity at 0.05 C, 1 C and 5 C are improved to 141.7, 125.0 and 89.5 mAh·g−1, which is partially resulting from the enhanced diffusion coefficient of lithium ions. The capacity retention ratio in 200 cycles at 0.5 C is 96.65%. The ex-situ XRD patterns after 200 cycles are nearly unchanged and the structure is proved to be very stable. The doping of Na+ can also inhibit the dissolution of Mn2+ and Fe2+ in the electrolyte. [ABSTRACT FROM AUTHOR]

Abstract In this work, abandoned chicken eggshell was used as hard biological template to synthesize battery material for the first time. We developed a simple hydrothermal method to form flocculent batt-like δ-MnO 2 nanoplatelets balls inside the pores of eggshell. Herein, eggshell was ground and screened into different mesh to prepare MnO 2 using the same method for comparison. MnO 2 made by similar eggshell-free method served as a contrast. The MnO 2 prepared from eggshell between 200 and 400 mesh has a large specific surface area up to 320.9 m2/g and a nanoplatelets ball structure capable of storing large amount of lithium ions. Most importantly, it shows the best electrochemical performances. At a current density of 100 mA/g, it delivered a high initial specific discharge/charge capacity of 2156.6/1008.2 mA h/g. After a short descent, its capacity gradually increased after about 30th cycle, and reached 1024.8/1022.1 mA h/g at the 100th cycle, much higher than that of MnO 2 from eggshell-free method and reported by others. Our original preparation method of using eggshell as hard biological template has referential significance of reducing particle size and advancing electrochemical performances for other battery materials. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

As a promising anode material, PbLi 2 Ti 6 O 14 has attracted the attention of many researchers. In this work, a series of PbLi 2 Ti 6 O 14 are prepared by solid state method at five different calcination temperatures and used as anode materials in lithium ion batteries. Through a series of tests, the results show that the phase purity, morphology and electrochemical performance of PbLi 2 Ti 6 O 14 can be seriously influenced by calcination temperature. When the calcination temperature is 900 °C, the phase-pure PbLi 2 Ti 6 O 14 can be obtained with relatively small particle size, excellent cycle performance and outstanding lithium ion diffusion behavior. It provides an initial charge capacity of 151.3 mA h g −1 at 100 mA g −1 . After 100 cycles, it shows a reversible capacity of 142.0 mA h g −1 with superior capacity retention of 93.85%. In contrast, PbLi 2 Ti 6 O 14 formed at 800 °C displays an unsatisfactory performance due to the presence of impurity, even though it has the smallest particle size and the largest lithium ion diffusion coefficient among the five samples. The reversible capacity is only 82.6 mA h g −1 after 100 cycles with capacity retention of 53.9%. In order to further study the lithium ion diffusion behavior of PbLi 2 Ti 6 O 14 , the in-situ X-ray diffraction technique is also implemented. It is found that during the lithiation/delithiation process, the stable framework can effectively inhibit the volume change and ensures the excellent electrochemical performance of PbLi 2 Ti 6 O 14 . [ABSTRACT FROM AUTHOR]

Metallic oxide ZnO is considered to be a promising alternative anode material for lithium ion battery because of its high theoretical capacities (978 mA h g −1 ). However, its inherent low electronic conductivity and undesirable large volume change result in inferior electrochemical performances and hinder its practical application. Herein, ZnO/ZnO@C composites are prepared by a simple carbonization process of ZnO/ZnO@ZIFs-8, which are constructed by using ZnO particles as both template and zinc sources for zeolitic imidazolate frameworks-8 (ZIF-8) preparation via a facile solution reaction. When evaluated as anode for lithium ion batteries, the as-prepared composites show an initial capacity of 878 mA h g −1 at current density of 0.1 A g −1 with high capacity retention of 95.6% after 50 cycles, and an initial capacity of 359 mA h g −1 tested at 5.0 A g −1 with a capacity retention of 85.3% after 500 cycles, exhibiting outstanding cycling stability and excellent rate capability. The ameliorated electrochemical performances are mainly attributed to the elevated conductivity and cushioning effects provided by carbon framework derived from ZIF-8, and the enhanced pseudocapacitance behavior originated from the decreased size of ZnO particles and high surface area of ZIFs-derived carbon. [ABSTRACT FROM AUTHOR]

It is necessary to build flexible and free-standing materials for flexible/wearable electronics in high-performance lithium-ions batteries. Herein, we design and fabricate a flexible and free-standing 3 D carbon/MoO 2 composite through a facile immersing method followed by an annealing process. The carbon framework is supported by non-woven cotton totally covered by graphene sheets. The nanosized MoO 2 particles were uniformly anchored on cotton fibers and graphene sheets. The structure has several advantages, such as an interconnected 3D electronically conductive network, plenty of channels for electrolyte solution cross, and more active points for the electrode reaction. Compared with cotton/MoO 2 (C/MoO 2 ) without graphene sheets, the CGN/MoO 2 composite (cotton covered by graphene/MoO 2 ) showed much better thermal stability and excellent cycling performance. The proposed synthesis process paves a new way as promising electrode materials for high power battery applications such as roll-up displays and wearable devices. [ABSTRACT FROM AUTHOR]

This study synthesized spinel LiMn 2 O 4 materials using a solid-state reaction processing technology. Neutral surfactants and the tri-block copolymer P123 (template) formed an organic self-assembly in alcohol (solvent), with LiCH 3 COO·2H 2 O and Mn(CH 3 COO) 2 ·4H 2 O as precursors of the inorganic skeleton. Changes in the structure, particle size, and surface area of LiMn 2 O 4 powder in relation to different surfactant contents were investigated. The changes in surface area should affect the wetting effect of the electrolyte on the cathode material, thereby further influencing the actual reaction area and charge–discharge efficiency. The results were analyzed to assess the effect of surface area on electrochemical performance of LiMn 2 O 4 cathode materials. X-ray diffraction (XRD) analysis data showed that LiMn 2 O 4 materials synthesized through the solid-phase reaction method are single-phase spinel, whose original structure is unaffected by the addition of surfactants. Scanning electron microscopic (SEM) observation revealed that LiMn 2 O 4 forms different spherical particles after the addition of different concentrations of surfactants. Furthermore, Brunauer–Emmett–Teller (BET) analysis showed that specific surface areas of 0.4–1.2 m 2 /g are relatively effective in enhancing the capacitance, similarly the formation of spherical particles is beneficial in enhancing the capacitance, and the high-current discharge efficiency is similar to the low-current discharge efficiency. As for the different concentrations of P123, the experiments added with 1.42 M P123 achieved optimum results. [ABSTRACT FROM AUTHOR]