Reactivating Dead Li by Shuttle Effect for High-Performance Anode-Free Li Metal Batteries

Anode-free Li metal batteries are considered the ultimate configuration for next-generation Li-based batteries due to the nonuse of excess Li metal and high energy density. However, the limited Li source worsens the issues in anode caused by Li dendrites and dead Li. Any Li loss in the formation of SEI and dead Li has a great influence on the full cell. Here, we introduce LiI with shuttle effect to suppress the Li dendrites and reactivate the dead Li in the anode-free LiFePO4 (LFP) |Cu full cells. During cycling, the iodine will transform between I and I3, and a chemical reaction will occur spontaneously between I3 and Li dendrites or dead Li. The generated Li in the electrolyte will be active in the following cycling. The anode-free LFP|Cu cells deliver an initial discharge capacity of 139 mAh g-1 and maintain capacities of 100 mAh g-1 with a capacity retention of 72% after 100 cycles. Both the anode-free LFP|Cu coin cells and pouch cells with LiI additive show much-improved performances. This work provides a new strategy for high-performance anode-free Li metal batteries.

Structure, Morphology and Electrochemical Characteristics of Na x MnO2 (x = 0.44, 0.67 and 0.8) as Cathode Materials for Na-Ion Batteries

The paper presents the results of the investigations of structural, morphological and electrochemical characteristics of Na x MnO2 (x = 0.44, 0.67 and 0.8) .It is shown that the crystal structure of the resulting materials is determined by the sodium content and is tunnel in a case of Na0.44MnO2 and layered in a case of Na0.67MnO2 and Na0.8MnO2. In addition, the materials obtained are characterized by different morphology. The initial discharge capacity of the materials obtained increases with the increase of sodium content in oxide phase and is 117, 139 and 151 mAh/g for Na0.44MnO2, Na0.67MnO2 and Na0.8MnO2, respectively, however, at the same time the stability of the specific capacity decreases. Using Na0.44MnO2 as an example, the effect of the electrolyte composition, in particular the presence of FEC, on its electrochemical characteristics is shown.

Tris(trimethylsilyl) phosphite (TMSPi) as an electrolyte additive for LiNi0.5Co0.2Mn0.3O2 cathode materials at elevated voltage and temperature

Electrolyte additive tris(trimethylsilyl) phosphite (TMSPi) was used to promote the electrochemical performances of LiNi[Formula: see text]Co[Formula: see text]Mn[Formula: see text]O2 (NCM523) at elevated voltage (4.5 V) and temperature (55[Formula: see text]C). The NCM523 in 2.0 wt.% TMSPi-added electrolyte exhibited a much higher capacity (166.8 mAh/g) than that in the baseline electrolyte (118.3 mAh/g) after 100 cycles under 4.5 V at 30[Formula: see text]C. Simultaneously, the NCM523 with 2.0 wt.% TMSPi showed superior rate capability compared to that without TMSPi. Besides, after 100 cycles at 55[Formula: see text]C under 4.5 V, the discharge capacity retention reached 87.4% for the cell with 2.0 wt.% TMSPi, however, only 24.4% of initial discharge capacity was left for the cell with the baseline electrolyte. A series of analyses (TEM, XPS and EIS) confirmed that TMSPi-derived solid electrolyte interphase (SEI) stabilized the electrode/electrolyte interface and hindered the increase of interface impedance, resulting in obviously enhanced electrochemical performances of NCM523 cathode materials under elevated voltage and/or temperature.

Effect of precursor particle size and morphology on lithiation of Ni0.6Mn0.2Co0.2(OH)2

In this paper, Ni0.6Mn0.2Co0.2(OH)2 precursors with several different morphologies and particle sizes are mixed with Li2CO3 and heat treated for 5, 7.5 and 10 h. The effects of the precursor properties on the degree of lithiation, electrochemical properties and volumetric capacities of lithiated product are compared. Based on the characterization results, a small (3 μm), narrow span precursor can be lithiated in a short period of time (5 h) and has good initial discharge capacity (185 mA h g− 1) and capacity retention (93% for 55 cycles). In contrast, a large wide-span precursor requires over 10 h for full lithiation. A highly porous precursor can be lithiated faster than traditional large wide-span materials, and has low cation mixing and good crystallinity. However, the volumetric energy density of porous material is low after lithiation compared to the other tested materials. Capacity retention after washing correlated with crystallographic properties of the sample. Graphic abstract

Synthesis and Electrochemical Performances of MnV2O6/rGO Nanocomposite as New Anode Material for Lithium-Ion Battery Application

Base on high theoretical capacity and synergistic effect of metal ions of transition metal vanadate composite, the MnV2O6/graphene (MnV2O6/rGO) nanocomposite was successfully synthesized through a hydrothermal method. The MnV2O6 nanoparticles were uniformly distributed and deposited on graphene networks. Benefited from the outstanding properties of the graphene nanosheets, the electrode conductivity was improved and the volume expansion was reduced. As an anode, the MnV2O6/graphene (MnV2O6/rGO) nanocomposite exhibited excellent lithium storage properties. An initial discharge capacity was 1350 mAh g-1, which increased to 1381 mAh g-1 after 100 cycles at 200 mA g-1, and showed a satisfactory reversible capacity of 640 mAh g-1 after 400 cycles at 5000 mA g-1.

Al-Doped Fe2O3 nanoparticles: advanced anode materials for high capacity lithium ion batteries

We successfully synthesized Al-Fe2O3 anode with high initial discharge capacity of 1210 mAh g−1 under 0.5 A g−1 and maintained around 900 mAh g−1 during the cycles. The doping of Al assists in the stability and electrochemical behavior of the whole electrode.

Effect of lithium borate coating on the electrochemical properties of LiCoO2 electrode for lithium-ion batteries

The effect of a protective coating of fused lithium borate, Li3BO3, on the physicochemical and electrochemical characteristics of LiCoO2 has been studied. A cathode material produced by the SCS method using binary organic fuel, glycine and citric acid. The influence of the experiment conditions on the morphology, crystal structure and specific surface of lithium cobaltite was studied. Electrochemical testing of LiCoO2∙nLi3BO3 samples, n = 5 and 7 mass %, has been performed in the cathode Li|Li+-electrolyte|LiCoO2∙nLi3BO3 half-cell using 1M LiPF6 in EC/DMC mixture (1:1) as electrolyte in the 2.7-4.3 V range at normalized discharge current С/10, С/5, С/2. The maximal initial discharge capacity of 185 mAh/g was detected for the samples with 5 mass % Li3BO3. The coulomb efficiency of optimal materials in the 40th cycle was 99.1%.

Precipitation and Calcination of High-Capacity LiNiO2 Cathode Material for Lithium-Ion Batteries

This article presents the electrochemical results that can be achieved for pure LiNiO2 cathode material prepared with a simple, low-cost, and efficient process. The results clarify the roles of the process parameters, precipitation temperature, and lithiation temperature in the performance of high-quality LiNiO2 cathode material. Ni(OH)2 with a spherical morphology was precipitated at different temperatures and mixed with LiOH to synthesize the LiNiO2 cathode material. The LiNiO2 calcination temperature was optimized to achieve a high initial discharge capacity of 231.7 mAh/g (0.1 C/2.6 V) with a first cycle efficiency of 91.3% and retaining a capacity of 135 mAh/g after 400 cycles. These are among the best results reported so far for pure LiNiO2 cathode material.

Synthesis and Electrochemical Properties of β-LiVOPO4/C as Cathode Materials for Lithium-Ion Batteries

Due to the high theoretical capacity, high platform voltage, stable structure, and mild conditions for synthesis, LiVOPO4 is expected to become the next generation of cathode materials for lithium-ion batteries (LIBs). However, due to the relatively weak ionic conductivity, its commercial application has been largely limited. The paper reported that acetylene black was used as the reducing agent and the pure phase nanostructured orthorhombic β-LiVOPO4 was obtained by carbothermal reduction method. A significant improvement in ionic conductivity was achieved, and the results were compared with previous studies, the initial discharge capacity of the material was considerably enhanced. The results show that the electrical conductivity and the initial discharge capacity of the material were also significantly improved. The sample obtained by holding at 600 °C for 10 h exhibited a maximum discharge capacity of 141.4 mAh g−1 between 3 V and 4.5 V at 0.05 C, with a value of 136.3 mAh g−1, retained after 50 cycles. This represents capacity retention of 96.39%.

Influence Comparison of Precursors on LiFePO4/C Cathode Structure for Lithium Ion Batteries

<p>Electricity is the most energy demanded in this era. Energy storage devices must be able to store long-term and portable. A lithium ion battery is a type of battery that has been occupied in a secondary battery market. Lithium iron phosphate / LiFePO₄ is a type of cathode material in ion lithium batteries that is very well known for its environmental friendliness and low prices. LiFePO₄/C powder can be obtained from the solid state method. In this study the variables used were the types of precursors : iron sulfate (FeSO₄), iron oxalate (FeC₂O₄) and FeSO₄+charcoal. Synthesis of LiFePO₄/C powder using Li:Fe:P at 1:1:1 %mol. Based on the XRD results, LiFePO₄/C from FeSO₄+charcoal shows the LiFePO₄/C peaks according to the JCPDS Card with slight impurities when compared to other precursors. XRD results of LiFePO₄/C with precursors of FeSO₄ or FeC₂O₄ shows more impurities peaks. This LiFePO₄/C cathode is paired with lithium metal anode, activated by a separator, LiPF₆ as electrolyte. Then this arrangement is assembled become a coin cell battery. Based on the electrochemical results, Initial discharge capacity of LiFePO₄/C from the FeSO₄ precursor is 19.72 mAh/g, while LiFePO₄/C with the FeC₂O₄ precursor can obtain initial discharge capacity of 17.99 mAh/g, and LiFePO₄/C with FeSO₄+charcoal exhibit initial discharge capacity of 21.36 mAh/g. This means that the presence of charcoal helps glucose and nitrogen gas as reducing agents.</p>