• Energy Research
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The limited fossil fuel supply toward carbon neutrality has driven tremendous efforts to replace fuel vehicles by electric ones. The recycling of retired power batteries, a core energy supply component of electric vehicles (EVs), is necessary for developing a sustainable EV industry. Here, we comprehensively review the current status and technical challenges of recycling lithium iron phosphate (LFP) batteries. The review focuses on: 1) environmental risks of LFP batteries, 2) cascade utilization, 3) separation of cathode material and aluminium foil, 4) lithium (Li) extraction technologies, and 5) regeneration and transformation of cathode materials. Detailed analyses are elaborated with case examples and technical challenges. Our critical analysis demonstrates that compared with retired lithium nickel cobalt manganese oxide (NCM) batteries, LFP batteries do not contain the high-value elements such as Co and Ni, so the economic drive for LFP recycling is compromised although future market prospects are substantial. It is of great practical significance to develop low-carbon and cost-effective Li extraction technologies and regeneration processes for cathode materials to ensure a sustainable and stable development of the LFP battery and EV industry.

Lignocellulosic paper waste constitutes a major waste stream globally, which should be valorised for chemical production. However, paper properties (e.g., feedstock composition, cellulosic crystallinity, and thermal stability/degradability) vary with raw materials and pulping processes. This study investigated levulinic acid (LA), hydroxymethylfurfural (HMF), and furfural production by H2SO4 and FeCl3 catalysed conversion of nine types of paper wastes in a green solvent system (1:1 γ-valerolactone/water). At 160-180 °C for 1-20 min, ∼23-27 wt% LA yield was achieved from sanitary papers, tracing/parchment paper, and paper food box mainly containing crystalline cellulose, while a lower LA yield (∼10-20 wt%) was obtained from other paper wastes with high contents of ash and lignin. A higher selectivity towards HMF (∼12 mol%) was achieved in the presence of FeCl3. A furfural yield of ∼ 4-7.5 wt% was also obtained from the hemicellulose content. This study elucidates crucial factors and desirable characteristics of paper waste for catalytic valorisation.