Direct reuse of LiFePO_(4)cathode materials from spent lithium-ion batteries:Extracting Li from brine

Due to the serious imbalance between demand and supply of lithium,lithium extraction from brine has become a research hotspot.With the demand for power lithium-ion batteries(LIBs)increased rapidly,a large number of spent LiFePO_(4)power batteries have been scrapped and entered the recycling stage.Herein,a novel and efficient strategy is proposed to extract lithium from brine by directly reusing spent LiFePO_(4)powder without any treatment.Various electrochemical test results show that spent LiFePO_(4)electrode has appropriate lithium capacity(14.62 mg_(Li)/g_(LiFePO_(4))),excellent separation performance(α_(Li-Na)=210.5)and low energy consumption(0.768 Wh/g_(Li))in electrochemical lithium extraction from simulated brine.This work not only provides a novel idea for lithium extraction from brine,but also develops an effective strategy for recycling spent LIBs.The concept of from waste to wealth is of great significance to the development of recycling the spent batteries.

Nano self-assembly of fluorophosphate cathode induced by surface energy evolution towards high-rate and stable sodium-ion batteries

In the field of materials science and engineering,controlling over shape and crystal orientation remains a tremendous challenge.Herein,we realize a nano self-assembly morphology adjustment of Na3V2(PO4)2F3(NVPF)material,based on surface energy evolution by partially replacing V3+with aliovalent Mn2+.Crystal growth direction and surface energy evolution,main factors in inducing the nano self-assembly of NVPF with different shapes and sizes,are revealed by high-resolution transmission electron microscope combined with density functional theory.Furthermore,NVPF with a two-dimensional nanosheet structure(NVPF-NS)exhibits the best rate capability with 68 mAh·g−1 of specific capacity at an ultrahigh rate of 20 C and cycle stability with 80.7%of capacity retention over 1,000 cycles at 1 C.More significantly,when matched with Se@reduced graphene oxide(rGO)anode,NVPF-NS//Se@rGO sodium-ion full cells display a remarkable long-term stability with a high capacity retention of 93.8%after 500 cycles at 0.5 C and−25°C.Consequently,experimental and theoretical calculation results manifest that NVPF-NS demonstrates such superior performances,which can be mainly due to its inherent crystal structure and preferential orientation growth of{001}facets.This work will promise insights into developing novel architectural design strategies for high-performance cathode materials in advanced sodium-ion batteries.