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Co- and Ni-free disordered rocksalt cathodes utilize oxygen redox to increase the energy density of lithium-ion batteries, but it is challenging to achieve good cycle life at high voltages >4.5 V (versus Li/Li+). Here we report a family of Li-excess Mn-rich cathodes that integrates rocksalt- and polyanion-type structures. Following design rules for cation filling and ordering, we demonstrate the bulk incorporation of polyanion groups into the rocksalt lattice. This integration bridges the two primary families of lithium-ion battery cathodes—layered/spinel and phosphate oxides—dramatically enhancing the cycling stability of disordered rocksalt cathodes with 4.8 V upper cut-off voltage. The cathode exhibits high gravimetric energy densities above 1,100 Wh kg−1 and >70% retention over 100 cycles. This study opens up a broad compositional space for developing battery cathodes using earth-abundant elements such as Mn and Fe.

Abstract: Needle‐like BiVO4 anode material for Na‐ion batteries was prepared by a simple solvothermal technique at 100 °C without further calcination. The BiVO4 electrode exhibited initial discharge (sodiation) capacity of 897 mAh /g with coulombic efficiency of 70.68% at 100 mA /g. The average coulombic efficiency was estimated at 93.07% and sodiation capacity predicted at 432 mAh/g upto 200 cycles. The average sodiation/desodiation capacity retention were found to be 52.07 and 68.10%, respectively for more than 100 cycles. The results demonstrate that needle‐like BiVO4 anode material offers an excellent electrochemical performance for large‐scale energy storage applications. [ABSTRACT FROM AUTHOR]

• N and S doped hard carbon anode (NS-MPC) derived from mango-peels biowastes for Na ion batteries is firstly demonstrated. • In-situ monitoring surface functional of mango-peel wastages via FT-IR analysis. • Heteroatoms doped-hard carbon anode exhibits superior electrochemical performance than un-doped sample. • The NS-MPC anode delivers a reversible discharge capacity of 400 mAh/g at 100 mA/g for 2500 cycles. Electrochemical energy storage devices, namely batteries are vital role to cut greenhouse gas secretions and reliable alternative of fossil fuel-used various electrical energy storage systems. Thus, the hard carbon is one of the promising cheapest sustainable material for energy storage sectors. In this study, we assemble the sodium-ion cell via renewable biomass-waste resource of mango-peels derived hard carbon (MPC) used as an anode electrode for Na-ion storage for the first-time. Furthermore, the hard carbon is modified with N, and S (NS-MPC) through a facile carbonization route. The structural, functional, morphological and chemical characteristics are systematically studied in details through spectroscopic techniques. The NS-MPC electrode consisted sodium-ion storage delivers a reversible discharge capacity of 400 mAh/g at a current density of 100 mA/g and exposed a reversible capacity of 155 mAh/g over 2500 cycles at 2 A/g. The Na-ion charge storage behavior reveals through the different rate controlled cyclic voltammetry (CV) analysis, which result exposed increasing contribution percentage of surface-controlled capacity with increment of current rates. Overall, this work signifies to protecting the environment by employed the bio-wastage to wealth applications, especially cost-effective fabrication of batteries for future pioneering grid energy storage applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Binary mixed transition-based metal oxides have some of the most potential as anode materials for rechargeable advanced battery systems due to their high theoretical capacity and tremendous electrochemical performance. Nonetheless, binary metal oxides still endure low electronic conductivity and huge volume expansion during the charge/discharge processes. In this study, we synthesized a reduced graphene oxide (rGO)-wrapped CoV 2 O 4 material as the anode for sodium ion batteries. The X-ray diffraction analyses revealed pure-phased CoV 2 O 4 (CVO) rGO-wrapped CoV 2 O 4 (CVO/rGO) nanoparticles. The capacity retention of the CVO/rGO composite anode demonstrated 81.6% at the current density of 200 mA/g for more than 1000 cycles, which was better than that of the bare one of only 73.5% retention. The as-synthesized CVO/rGO exhibited remarkable cyclic stability and rate capability. The reaction mechanism of the CoV 2 O 4 anode with sodium ions was firstly studied in terms of cyclic voltammetry (CV) and ex situ XRD analyses. These results articulated the manner of utilizing the graphene oxide-coated spinel-based novel anode-CoV 2 O 4 as a potential anode for sodium ion batteries.