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High-entropy oxides (HEOs) have attracted increasing attention due to their extreme chemical disorder incorporated in long-range structural order. Various single-phase HEOs have been successfully fabricated through solid-state synthesis, yet the resulting materials are often bulky aggregates. Solution-based chemical reactions can be applied to prepare HEO particles. However, the co-precipitation of multiple metal ions is practically challenging, given that the composition of a precipitated HEO can deviate significantly from an equimolar ratio. Here, coordination polymerization has been coupled with solid dispersant-assisted annealing, producing single-crystalline HEO rods with uniform dispersion. The stepwise polymerization of cations into metal–organic chains (MOCs) enables homogeneous deposition of different metals into submicron-sized particles. Owing to this pre-mixing feature of oxalate precursors, single-phase HEOs can be obtained through short annealing. While this deposition method extends the compositional spectrum of rocksalt HEO to other metals and simplifies the production of HEO particles with single-crystalline structures, solid dispersants enable the retention of the morphology and dispersity of precursor particles after annealing. The resulting HEO single crystals demonstrate impressive cycle performance in half-cell and full-cell configurations. [ABSTRACT FROM AUTHOR]

Abstract: Spinel Li4Ti5O12 was synthesized via a high temperature ball milling route with the assistance of ultrasonic dispersion, mechanical agitation, and glucose monohydrate solid phase dispersant, respectively. The crystal structures and the electrochemical properties of the as-prepared Li4Ti5O12 were systematically investigated. The results showed the as-prepared samples were highly-crystalline and exhibited high capacities and good cycle stabilities. The initial discharge capacity of sample C5 mixed with 5% glucose monohydrate reached 187.003mAh/g at 0.1C-rate, and retained at 183.509mAh/g after 20 cycles. This facile solid phase dispersant-assisted high temperature ball milling method could be an excellent way to synthesize Li4Ti5O12 for practical applications. [Copyright &y& Elsevier]

Abstract: A novel approach has been developed to synthesize lithium titanate assembled by highly-crystalline micron-sized particles. The fabrication process was very simple, involving only a high temperature ball milling method with Li2CO3 and amorphous TiO2 as starting materials. The ball milling and its influence on the synthesis temperature, the morphology and electrochemical performance of Li4Ti5O12 were uniformly investigated in this paper. The results showed the dispersion of Li4Ti5O12 powder with sizes of around 0.5–2μm and with an irregular shape. Results from the discharge measurements indicated that the sample A2 synthesized at 750°C exhibited an excellent initial discharge capability of 170.313mAh/g at 0.1 C-rate. After 16 cycles, the capacity retention was 91.6%. This facile high temperature ball milling method could be an expectant practical powder technology for the synthesis of Li4Ti5O12 in industrial production. [Copyright &y& Elsevier]