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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.

Silicon is a promising anode material for high-performance Li-ion batteries as a result of its high theoretical specific capacity and elemental abundance. Currently, the commercial application of the Si-based anode is still restricted by its large volume changes during the lithiation cycles and low electrical conductivity. To address these issues, we demonstrate a facile plasma-assisted discharge process to anchor nano-sized Si particles into methanol with quick quenching. After the subsequent sintering process, we obtained a Si/SiC/C composite (M-Si). The unique structure not only allowed for the electrolyte infiltration to enhance lithium ion diffusion during charge and discharge process, but also buffered the volume expansion of silicon particles to enhance the rate capability and cycle stability. The M-Si cell electrochemical results exposed good Li-ion storage performance compared to that of the bare Si used cell (B-Si). The electrode cell consisting of M-Si exhibited remarkable enhanced cyclic stability and sustained the reversible specific capacity of 563 mAhg−1 after 100 cycles, with a coulombic efficiency of 99% at a current density of 0.1C, which is higher than that of the B-Si electrode cell that was used. Hence, the as-prepared Si/SiC/C composite is an efficient anode material for Li-ion battery applications. Moreover, these results indicate that the novel plasma-assisted discharge technique will bring a potential durable methodology to produce novel high-performance electrode materials for future advanced large-scale energy-storage applications. [ABSTRACT FROM AUTHOR]

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]

Mesoporous spinel ZnMn 2 O 4 (ZMO) microspheres as potential anode materials for sodium-ion batteries are prepared using the polyvinyl pyrrolidone (PVP)-assisted solvothermal technique. A one-step heat treatment process with heating varying from 1 to 5 °C min−1 is used to reveal the crystal phase purity and tuning of porosity of the as-prepared materials. The ZnMn 2 O 4 synthesized by heating rate of 1 °C min−1 exhibits the highest specific surface area (47.016 m2 g−1) and pore size (23.342 nm). The slow heating rate sample exhibited better capacity and rate capability compared with the sample with the fast heating rate. The electrochemical reaction mechanism is epitomized by ex-situ X-ray powder diffraction/X-ray photoelectron spectroscopy analyses that revealed the conversion mechanism of the ZnMn 2 O 4 electrode during charge and discharge processes. The results indicate that PVP-assisted approach provide porous microspheres of ZnMn 2 O 4 demonstrates enhanced electrochemical performance due to a larger surface area and porosity to facilitate faster Na+ diffusion kinetics. Image 1 • Spinel ZnMn2O4 material produced by solvothermal with post heat treatment route. • PVP assistance with slow heating rate synergistically improves the microstructure. • Superior Na-ion storage exhibits slow ramp rate comparably high ramp rates. • Reaction mechanism was investigated by ex-situ XRD/XPS analyses. [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 CoV2O4 material as the anode for sodium ion batteries. The X-ray diffraction analyses revealed pure-phased CoV2O4 (CVO) rGO-wrapped CoV2O4 (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 CoV2O4 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-CoV2O4 as a potential anode for sodium ion batteries. [ABSTRACT FROM AUTHOR]

A series of Na 3-x V 2 (PO 4-x F x ) 3 (x = 0, 0.1, 0.15 and 0.3) polyanion cathode materials are synthesized via a sol-gel method. The optimal doping concentration of F in Na 3 V 2 (PO 4 ) 3 is 0.15 mol %. By neutron powder diffraction data, the chemical composition of as-synthesized material is Na 2.85 V 2 (PO 3.95 F 0.05 ) 3 . The half-cell of Na 2.85 V 2 (PO 3.95 F 0.05 ) 3 cathode exhibits a stable discharge capacity of 103 mAh g -1 and 93% of capacity retention over 250 cycles without decay at 0.1 A g -1 , which is higher than that of bare Na 3 V 2 (PO 4 ) 3 (98 mAh g -1 ). The high rate capability of Na 2.85 V 2 (PO 3.95 F 0.05 ) 3 is also dramatically enhanced via increase the conductivity of host material by F-doping. Moreover, the symmetrical Na-ion full-cell is fabricated using Na 2.85 V 2 (PO 3.95 F 0.05 ) 3 as cathode and anode materials. It is achieved that the good reversibility and superior cycling stability about 98% of capacity retention with ~100% of coulombic efficiency at 1.0 A g -1 throughout 1000 cycles. These results demonstrate that the optimal amount of Na 2.85 V 2 (PO 3.95 F 0.05 ) 3 is a distinctive potential candidate for excellent long-term cyclic stability with high rate low-cost energy storage applications.