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Cathodes in lithium‐ion batteries with anionic redox can deliver extraordinarily high specific capacities but also present many issues such as oxygen release, voltage hysteresis, and sluggish kinetics. Identifying problems and developing solutions for these materials are vital for creating high‐energy lithium‐ion batteries. Herein, the electrochemical and structural monitoring is conducted on lithium‐rich cathodes to directly probe the formation processes of larger voltage hysteresis. These results indicate that the charge‐compensation properties, structural evolution, and transition metal (TM) ions migration vary from oxidation to reduction process. This leads to huge differences in charge and discharge voltage profile. Meanwhile, the anionic redox processes display a slow kinetics process with large hysteresis (≈0.5 V), compared to fast cationic redox processes without any hysteresis. More importantly, a simple yet effective strategy has been proposed where fine‐modulating local oxygen environment by the lithium/oxygen (Li/O) ratio tunes the anionic redox chemistry. This effectively improves its electrochemical properties, including the operating voltage and kinetics. This is also verified by theoretical calculations that adjusting anionic redox chemistry by the Li/O ratio shifts the TM 3d—O 2p bands and the non‐bonding O 2p band to a lower energy level, resulting in a higher redox reaction potential. [ABSTRACT FROM AUTHOR]

Due to the high energy density and low cost, LiNi1/3Co1/3Mn1/3O2 is wildly explored as a promising cathode material for lithium-ion batteries. However, this material suffers from the destruction of surface structure in the electrolyte and the reacting of electrode with the electrolyte during cycles in highly voltage. Herein, we rationally designed core-shell nanostructure LiNi1/3Mn1/3Co1/3O2@ ultrathin δ-MnO2 nanoflakes cathode material with excellent capacity retention and rate capacity by a liquid-phase precipitation method. The unique ultrathin δ-MnO2 nanoflakes shell nanostructure plays a key role in effectively improving rate performance and cycle life of LiNi1/3Co1/3Mn1/3O2. The electrode with the coating amount of 3 wt% exhibits excellent cycle performance and superior rate capacity compared with bare electrode. The δ-MnO2 nanoflakes-coated layer can react with Li+ during cycling and convert to spinel phase, resulting in a reversibly de/lithiation coating layer to improve its specific capacity compared with other inactive coating layer, and the spinel phase can also provide a three-dimensional lithium ions diffusion channels and thus promote lithium ions diffusion. Judging from the discussion, it can be concluded that the role of δ-MnO2-nanoflakes coating layer not only acts as a protective layer to impede the electrode directly contact with electrolyte but also accelerates lithium ions diffusion and improve its specific capacity. [ABSTRACT FROM AUTHOR]

The application of SiO anodes in Li‐ion batteries is greatly restricted by its low initial coulombic efficiency (ICE). Usually, a pre‐lithiation procedure is necessary to improve the ICE, but the available technologies are associated with safety issues. Metal (M)‐mixed SiO shows great promise to address these issues by reactivating Li2O through the reaction M+Li2O→MOx+Li+, which is the inverse reaction to that occurring at MOx anodes. Sn is found to be a good choice of metal for this concept. Nanoscale Sn‐mixed SiO composites are prepared by mechanical milling. Sn forms an outstanding conductive phase, which boosts the reaction kinetics and also reactivates the Li2O byproduct. Sn/SiO (1:2 w/w) delivers a significant improvement in ICE from 66.5 % to 85.5 %. A higher ICE value of >90 % is obtained when the Sn content is ≥50 wt %. However, additional electrolyte decomposition occurs, which is catalyzed by Sn. In addition, coarsening of the nano‐Sn material reduces the inverse conversion reactivity of Sn/Li2O and subsequently results in rapid capacity fading. The quantitative analysis indicates that, in contrast to transition metals, the alloying and dealloying nature of Sn gives a 50 % improvement in reversible capacity, attributed to Sn/Li2O. This work gives a general strategy to choose metals for increasing the ICE of SiOx and metal oxides. [ABSTRACT FROM AUTHOR]

The research of organic materials thrives for lithium‐ion and sodium‐ion batteries but lacks for aqueous Zn2+ batteries. Herein, we prepared 1,4,5,8‐naphthalene diimide (NTCDI), which is derived from 1,4,5,8‐naphthalenetetracarboxylic dianhydride, through nitrogen substitution with the assistance of ammonia solution. NTCDI is first applied in aqueous Zn2+ batteries, which can give a high reversible capacity of 240 mAh g−1 at 0.1 A g−1. The electrochemical kinetics analysis indicates that the diffusion‐control process dominates in the electrode reaction. NTCDI can keep 73.7 % of the initial capacity of 152 mAh g−1 after 2000 continuous charge/discharge cycles at 1 A g−1, showing great potential for zinc storage. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries are widely considered as promising next generation energy storage devices due to their high energy density and low cost. However, the shuttle effect and sluggish kinetics of polysulfide conversion are still key challenges for practical application. Herein, we designed hierarchical nitrogen-doped carbon nanotubes/ultrathin molybdenum disulfide nanosheets in a core–shell architecture (denoted as NC@MoS2) to alleviate the shuttle effect and propel redox reaction kinetics, thereby improving the electrochemical performance of lithium–sulfur batteries. Both experimental investigations and theoretical studies reveal that MoS2 nanosheets can chemically immobilize lithium polysulfides and catalyze the conversion of polysulfides. Moreover, this unique core–shell architecture could facilitate rapid electrical transport and favorable electrolyte infiltration. We have demonstrated that the obtained S–NC@MoS2 cathodes exhibit excellent rate capability (516 mA h g−1 at 5C) and superior cycle stability (only 0.049% capacity decay per cycle up to 1000 cycles at 2C). Remarkably, the composite cathode with a high sulfur loading of 3.6 mg cm−2 still maintains high rate capability and stable cycling performance over 300 cycles. This work offers a new strategy to develop high-performance lithium–sulfur batteries through the exploration of two-dimensional mediator catalysts. [ABSTRACT FROM AUTHOR]

La2O3-coated LiNi1/3Mn1/3Co1/3O2 has been successfully synthesized via a wet chemical process followed. The 3 wt% La2O3-coated LiNi1/3Mn1/3Co1/3O2 illustrated highest rate capability, lowest voltage decay, outstanding cycling performance, and excellent energy density at the range of 2.5–4.5 V. The discharge capacity of LiNi1/3Mn1/3Co1/3O2 at a 5C rate increases from 86.9 to 137.5 mA h g−1 upon coating with La2O3 particles. The decrements of the average discharge voltages for 3 wt% La2O3-coated LiNi1/3Mn1/3Co1/3O2 electrode is 10.3 mV over 100th cycle and 26.9 mV over 200th cycle compared to 407 mV over 100th cycle for bare nickel cobalt manganese. The energy densities retention of 3 wt% La2O3-coated LiNi1/3Mn1/3Co1/3O2 is 96.5% after 100 cycles and 89.7% after 200 cycles compared to 34.5% after 100 cycles for bare LiNi1/3Mn1/3Co1/3O2. Universal but efficient, it can also be suitable to coat other layered cathode materials to ameliorate their electrochemical properties. [ABSTRACT FROM AUTHOR]