Solid polymer electrolytes (SPEs) are promising for achieving safe solid-state Li metal batteries (SSLMBs). However, unstable electrode/electrolyte interface contact of SPEs limits their application at high voltage. To address this issue, we designed a multi-layer asymmetric SPE with a sandwich structure based on the hydroxyapatite (HAP) enhanced PVDF-HFP matrix. Two different interfacial modification layers were introduced on the anode and cathode sides. Methyl (2,2,2-trifluoromethyl) carbonate (FEMC) and tetramethylene sulfone (TMS) were selected as plasticizers in the layers, respectively, contacting the anode and cathode to reduce the reactivity of the anode interface and enhance the high-voltage compatibility of the cathode interface. Unlike usual designs, each layer of the asymmetric SPE has essentially the same composition except the plasticizers, effectively eliminating interface resistance and promoting Li+ fast migration. Consequently, the asymmetric SPE exhibits excellent io
Fastmarkets analysts Muthu Krishna and Phoebe O'Hara look at the potential of solid-state and sodium-ion batteries to scale up and ease the pressure on lithium-ion NMC and LFP battery chemistries, which currently dominate the EV and ESS markets.
Polyethylene oxide (PEO) based polymer electrolytes is promising for all-solid-state lithium metal batteries (ASSLMBs). Solid-electrolyte-interface (SEI) layer formed between polymer electrolytes and lithium metal is crucial to inhibit lithium dendrites growth. Herein, mild fluorination on commercial PEO is engineered as an electrolyte for ASSLMBs, which shows an outstanding cycling stability. During this process, some C-H bonds in PEO chains are substituted with C-F bonds, resulting in the formation of fluorinated PEO (F-PEO) with a low fluorine content of 2.7 at.%. Fluorination alters the regularity of PEO chains, leading to an improved ion conductivity for F-PEO/LiTFSI. An unusual and stable SEI containing relatively high LiF content forms, which can inhibit lithium dendrites growth and boost the battery performance. Li/Li cell with F-PEO/LiTFSI delivers outstanding cycling stability over 2000 h at 0.1 mA cm-2. When matching with LiFePO4 cathode, the battery exhibits high capacity o
Solid polymer electrolytes (SPEs) are one of the most promising alternatives to flammable liquid electrolytes for building safe Li metal batteries. Nevertheless, the poor ionic conductivity at room temperature (RT) and low resistance to Li dendrites seriously hinder the commercialization of SPEs. Herein, we design a bifunctional flame retardant SPE by combining hydroxyapatite (HAP) nanomaterials with N-methyl pyrrolidone (NMP) in the PVDF-HFP matrix. The addition of HAP generates a hydrogen bond network with the PVDF-HFP matrix and cooperates with NMP to facilitate the dissociation of LiTFSI in the PVDF-HFP matrix. Consequently, the prepared SPE demonstrates superior ionic conductivity at RT, excellent fireproof properties, and strong resistance to Li dendrites. The assembled Li symmetric cell with prepared SPE exhibits a stable cycling performance of over 1200 h at 0.2 mA cm−2, and the solid-state LiFePO4||Li cell shows excellent capacity retention of 85.3% over 600 cycles at 0.5 C.
Sodium-ion batteries are seeing a surge in interest as a potential complementary energy storage technology in light of skyrocketing demand for lithium-ion batteries. One of the frontiers of improving sodium-ion battery competitiveness is replacing liquid electrolytes with polymer electrolytes, which contain no free-flowing solvent, to increase safety and reduce cost. Their development may one day make viable sodium-metal batteries, which would have considerable advantages in energy density. This review provides an overview of the current field of both solid-polymer and gel-polymer electrolytes for sodium-ion batteries, with a focus in the key performance parameters used to assess them. In particular, their targeted manipulation and significance for practical use are discussed. A major theme is also the interdependence of many electrochemical and mechanical properties. In addition, a quantitative comparison of hitherto reported values for these parameters across various polymer classes