N-doped engineering of a high-voltage LiNi0.5Mn1.5O4 cathode with superior cycling capability for wide temperature lithium-ion batteries

High performance of 5 V LiNi0.5Mn1.5O4 cathode materials synthesized from recycled Li2CO3 for sustainable Lithium-Ion batteries

Lithium has become a critical element in the modern era due to the emergence of lithium-ion battery (LIB) technologies as a mean to lessen the environmental burden created by the energy usage from conventional sources. In this study, Li2CO3 was obtained from spent LIBs using a hydrometallurgical method and sintered with Taylor Flow Reactor (TFR) synthesized Ni0.25Mn0.75(OH)2 precursor to synthesize high-voltage LiNi0.5Mn1.5O4 (R-LNMO) cathode material for the first time and conducted a series of tests and inspections for structure, morphology, electrochemical lithium cycling behaviour and its controlling factors, electronic conductivity, lithium ion diffusion characteristics and self-discharge behaviour. The results are benchmarked with C-LNMO synthesized through a similar processing but using Li2CO3 obtained from a commercial source. It was found that R-LNMO shows a higher crystal stability than the C-LNMO based on the in-situ oxygen gas-evolution results and lower angle shift in post-mortem X-ray diffraction (XRD) analysis after 500 cycles at 1C/1C, and it could be seen that both LNMO samples have good structural reversibility performance during in-situ XRD analysis. In the long-term testing, R-LNMO outperformed C-LNMO in both average discharge capacity (123.17mAh g-1vs. 119.67mAh g-1) and capacity retention (94.66 % vs. 89.66 %) after 500 cycles at 1C/1C.Thus, our test results indicated that this recycled Li2CO3 showed the highly promising potential for reuse in various high-energy-density cathode materials preparation for LIBs re-applications.

Subtractive transformation of cathode materials in spent Li-ion batteries to a low-cobalt 5 V-class cathode material

Adding extra raw materials for direct recycling or upcycling is prospective for battery recycling, but overlooks subtracting specific components beforehand can facilitate the recycling to a self-sufficient mode of sustainable production. Here, a subtractive transformation strategy of degraded LiNi0.5Co0.2Mn0.3O2 and LiMn2O4 to a 5 V-class disordered spinel LiNi0.5Mn1.5O4-like cathode material is proposed. Equal amounts of Co and Ni from degraded materials are selectively extracted, and the remaining transition metals are directly converted into Ni0.4Co0.1Mn1.5(CO3)2 precursor for preparing cathode material with in-situ Co doping. The cathode material with improved conductivity and bond strength delivers high-rate (10 C and 20 C) and high-temperature (60 °C) cycling stability. This strategy with no extra precursor input can be generalized to practical degraded black mass and reduces the dependence of current cathode production on rare elements, showing the potential of upcycling from the spent to a next-generation 5 V-class cathode material for the sustainable Li-ion battery industry.

Challenges and Advances in Rechargeable Batteries for Extreme-Condition Applications

Rechargeable batteries are widely used as power sources for portable electronics, electric vehicles and smart grids. Their practical performances are, however, largely undermined under extreme conditions, such as in high-altitude drones, ocean exploration and polar expedition. These extreme environmental conditions not only bring new challenges for batteries but also incur unique battery failure mechanisms. To fill in the gap, it is of great importance to understand the battery failure mechanisms under different extreme conditions and figure out the key parameters that limit battery performances. In this review, the authors start by investigating the key challenges from the viewpoints of ionic/charge transfer, material/interface evolution and electrolyte degradation under different extreme conditions. This is followed by different engineering approaches through electrode materials design, electrolyte modification and battery component optimization to enhance practical battery performances. Finally, a short perspective is provided about the future development of rechargeable batteries under extreme conditions.

Alginate-Xylan Biopolymer as a Multifunctional Binder for 5 V High-Voltage LNMO Electrodes

LiNi_0.5Mn_1.5O₄ (LNMO) with a spinel structure is one of the most promising cathode materials choices for Li-ion batteries (LIBs). However, at a high operating voltages, the decomposition of organic electrolytes and the dissolution of transition metals, especially Mn(II) ions, cause unsatisfactory cycle stability. The initial application of a sodium alginate (SA)-xylan biopolymer as an aqueous binder aims to address the aforementioned problems. The SX28-LNMO electrode has a sizable discharge capacity, exceptional rate capability, and long-term cyclability with a capacity retention of 99.8% after 450 cycles at 1C and a remarkable rate capability of 121 mAh g^-1 even at 10C. A more thorough investigation illustrated that SX28 binder provides a substantial adhesion property and generates a uniform (CEI) layer on the LNMO surface, suppressing electrolytes' oxidative decomposition upon cycling and improving LIB performances. This work highlights the potential of hemicellulose as an aqueous binder for 5.0 V high-voltage cathodes.