Solid polymer electrolyte batteries with a Li-metal anode and high-voltage active materials hold promising prospects to increase the energy density and improve the safety of conventional Li-ion batteries. An adequate choice of the polymers used for the cathode (catholyte) and for the separator (electrolyte) to create a sufficient energy gap and improve the chemical compatibility at both the positive electrode and Li-metal anode is required. The present work highlights the advantages of the double-layer polymer electrolyte approach in cells with a LiNi x Mn y Co z O2 active material, a poly­(propylene carbonate) (PPC) catholyte, and a poly­(ethylene oxide) (PEO) electrolyte. Replacing PEO in the catholyte with PPC results in a remarkably improved cycling performance. In addition, the higher lithium transference number of electrolytes with single lithium ion conductors leads to a smooth cycling of solid-state batteries. Cells with 1 mAh cm–2 deliver 160 mAh g–1, with a capacity retention above 80% over 80 cycles and a Coulombic efficiency close to 100%.

High-voltage Li metal solid-state batteries are in the spotlight of high energy and power density devices for the next generation of batteries. However, the lack of robust solid-electrolyte interfaces (SEI)...

No abstract

Despite the efforts devoted to the identification of new electrode materials with higher specific capacities and electrolyte additives to mitigate the well-known limitations of current lithium-ion batteries (LIBs), this technology is believed to have almost reached its energy density limit. It suffers also of a severe safety concern ascribed to the use of flammable liquid-based electrolytes. In this regard, solid-state electrolytes (SSEs) enabling the use of lithium metal as anode in the so-called solid-state lithium metal batteries (SSLMBs) are considered as the most desirable solution to tackle the aforementioned limitations. This emerging technology has rapidly evolved in recent years thanks to the striking advances gained in the domain of electrolyte materials, where SSEs can be classified according to their core chemistry as organic, inorganic, and hybrid/composite electrolytes. This strategic review presents a critical analysis of the design strategies reported in the field of SSEs, summarizing their main advantages and disadvantages, and providing a future perspective toward the rapid development of SSLMB technology.

No abstract

Current lithium-ion batteries are close to reaching their physicochemical energy density limit. Moreover, they present high operation risks regarding their liquid electrolyte. Solid-state batteries are a promising alternative to overcome these problems. They offer safe operation, and potentially improved energy and power density. The option of operating at higher voltages has led to the possibility of employing high capacity electrodes. In this study, the synthesis of a nanostructured anode through electrospinning was carried out. This electrode is based on polymer nanofibres with intercalated graphite particles. The effect of molecular weight, voltage, temperature and humidity has been studied for the formation of smooth and uniform nanofibres. At the optimized conditions, Polyethylene oxide (PEO)-Polyethylene glycol (PEG) nanofibres with diameters around 600 nm were successfully electrospun. The effect of graphite loading on the electrospinning of this solution was also studied. A 30% graphite particle loading in the final fibres was reached with a reproducible methodology. It was found that the electrospun graphite particles received a polymer coating during electrospinning. EDX analysis confirmed that most of the graphite particles are covered by a polymer layer, confirming this hypothesis. Even if it is unclear how this affects the behaviour of the graphite for energy storage, high graphite content was electrospun together with PEO nanofibres with a new methodology.

Self-standing carbon fiber electrodes hold promise for solid-state battery technology owing to their networked structures improving interparticle connectivity, robustness contributing to mechanical integrity, and surface sites confining Li dendrites. We here evaluate carbonized 3D electrospun fibers filled with polymer electrolytes as anodes in solid-state lithium half cells. Microscopic analysis of the cells demonstrates the high wettability of carbon fibers with electrolytes, promoting an intimate contact between electrolytes and fibers. Solid-state cells delivered high initial capacities up to ∼300 mAh g−1, although the latter cycles were characterized by gradual capacity fade (∼100 mAh g−1 in the 100th cycle with nearly 100% coulombic efficiency), attributed to the onset of parasitic reactions increasing the cell resistance and polarization. When these were benchmarked against similar cells but with the liquid electrolyte, it was found that Li storage in these fiber electrodes is intermediate between graphite and hard carbon in terms of lithiation voltage (vs Li/Li+), corroborating with the nature of carbon assessed by XRD and Raman analysis. These observations can contribute to further development and optimization of solid-state batteries with 3D electrospun carbon fiber electrodes.

No abstract