In Situ Fabricated Non-Flammable Quasi-Solid Electrolytes for Li-Metal Batteries.

Lithium metal batteries (LMBs) are viewed as one of the most promising high energy density battery systems, but their practical application is hindered by significant fire hazards and fast performance degradation due to the lack of a safe and compatible configuration. Herein, nonflammable quasi-solid electrolytes (NQSEs) are designed and fabricated by using the in situ polymerization method, in which 1,3,2-dioxathiolan-2,2-oxide is used as both initiator to trigger the in situ polymerization of solvents and interphase formation agent to construct robust interface layers to protect the electrodes, and triethyl phosphate as a fire-retardant agent. The NQSEs show a high ionic conductivity of 0.

Achieving Practical High-Energy-Density Lithium-Metal Batteries by a Dual-Anion Regulated Electrolyte.

Lithium-metal batteries (LMBs) using lithium-metal anodes and high-voltage cathodes have been deemed as one of the most promising high-energy-density battery technology. However, its practical application is largely hindered by the notorious dendrite growth of lithium-metal anodes, the fast structure degradation of the cathode, and insufficient electrode-electrolyte interphase kinetics. Here, a dual-anion regulated electrolyte is developed for LMBs using lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) and lithium difluoro(bisoxalato)phosphate (LiDFBOP) as anion regulators.

Formation of LiF-rich Cathode-Electrolyte Interphase by Electrolyte Reduction.

The capacity of transition metal oxide cathode for Li-ion batteries can be further enhanced by increasing the charging potential. However, these high voltage cathodes suffer from fast capacity decay because the large volume change of cathode breaks the active materials and cathode-electrolyte interphase (CEI), resulting in electrolyte penetration into broken active materials and continuous side reactions between cathode and electrolytes. Herein, a robust LiF-rich CEI was formed by potentiostatic reduction of fluorinated electrolyte at a low potential of 1.

A nitroaromatic cathode with an ultrahigh energy density based on six-electron reaction per nitro group for lithium batteries.

Organic electrode materials have emerged as promising alternatives to conventional inorganic materials because of their structural diversity and environmental friendliness feature. However, their low energy densities, limited by the single-electron reaction per active group, have plagued the practical applications. Here, we report a nitroaromatic cathode that performs a six-electron reaction per nitro group, drastically improving the specific capacity and energy density compared with the organic electrodes based on single-electron reactions.

Interfacial Design for a 4.6 V High-Voltage Single-Crystalline LiCoO Cathode.

Single-crystalline cathode materials have attracted intensive interest in offering greater capacity retention than their polycrystalline counterparts by reducing material surfaces and phase boundaries. However, the single-crystalline LiCoO suffers severe structural instability and capacity fading when charged to high voltages (4.6 V) due to Co element dissolution and O loss, crack formation, and subsequent electrolyte penetration.

Soluble Organic Cathodes Enable Long Cycle Life, High Rate, and Wide-Temperature Lithium-Ion Batteries.

Organic electrode materials free of rare transition metal elements are promising for sustainable, cost-effective, and environmentally benign battery chemistries. However, severe shuttling effect caused by the dissolution of active materials in liquid electrolytes results in fast capacity decay, limiting their practical applications. Here, using a gel polymer electrolyte (GPE) that is in situ formed on Nafion-coated separators, the shuttle reaction of organic electrodes is eliminated while maintaining the electrochemical performance.

A poorly soluble organic electrode material for high energy density lithium primary batteries based on a multi-electron reduction.

Here we report an organic cathode material with poor solubility for lithium primary batteries, indeno[3,2-]fluorene-6,12-dione. Each carbonyl group experiences a four-electron reduction to a methylene group, resulting in a high energy density of 1392 W h kg, which is among the best results for organic electrode materials.

Storage Mechanism of Alkali Metal Ions in the Hard Carbon Anode: an Electrochemical Viewpoint.

The storage mechanisms of Li, Na, and K in hard carbon anodes are investigated through systematically exploring their electrochemical behaviors. Two charge/discharge voltage regions are observed for all the Li, Na, and K storage, a slope at a high voltage, and a plateau in a low-voltage range. Considerably different behaviors are revealed by the galvanostatic intermittent titration technique and electrochemical impedance spectroscopy measurements, and accordingly different storage mechanisms are proposed.

Electrolytes and Interphases in Potassium Ion Batteries.

Potassium ion batteries (PIBs) are recognized as one promising candidate for future energy storage devices due to their merits of cost-effectiveness, high-voltage, and high-power operation. Many efforts have been devoted to the development of electrode materials and the progress has been well summarized in recent review papers. However, in addition to electrode materials, electrolytes also play a key role in determining the cell performance.

A Lithium-Organic Primary Battery.

Lithium primary batteries are still widely used in military, aerospace, medical, and civilian applications despite the omnipresence of rechargeable Li-ion batteries. However, these current primary chemistries are exclusively based on inorganic materials with high cost, low energy density or severe safety concerns. Here, a novel lithium-organic primary battery chemistry that operates through a synergetic reduction of 9,10-anthraquinone (AQ) and fluoroethylene carbonate (FEC) is reported.

Bismuth Nanoparticle@Carbon Composite Anodes for Ultralong Cycle Life and High-Rate Sodium-Ion Batteries.

Bismuth has emerged as a promising anode material for sodium-ion batteries (SIBs), owing to its high capacity and suitable operating potential. However, large volume changes during alloying/dealloying processes lead to poor cycling performance. Herein, bismuth nanoparticle@carbon (Bi@C) composite is prepared via a facile annealing method using a commercial coordination compound precursor of bismuth citrate.

Room-Temperature Potassium-Sulfur Batteries Enabled by Microporous Carbon Stabilized Small-Molecule Sulfur Cathodes.

Potassium-sulfur (K-S) batteries are a promising alternative to lithium ion batteries for large-area energy storage applications, owing to their high capacity and inexpensiveness, but they have been seldom investigated. Here we report room-temperature K-S batteries utilizing a microporous carbon-confined small-molecule sulfur composite cathode. The synergetic effects of the strong confinement of microporous carbon matrix and the small-molecule sulfur structure can effectually eliminate the formation of soluble polysulfides and ensure a reversible capacity of 1198.

Conjugated Microporous Polymers with Tunable Electronic Structure for High-Performance Potassium-Ion Batteries.

Conjugated microporous polymers (CMPs) with π-conjugated skeletons show great potential as energy storage materials due to their porous structure and tunable redox nature. However, CMPs and the structure-performance relationships have not been well explored for potassium-ion batteries (KIBs). Here, we report the structure-engineered CMP anodes with tunable electronic structures for high-performance KIBs.

Marriage of an Ether-Based Electrolyte with Hard Carbon Anodes Creates Superior Sodium-Ion Batteries with High Mass Loading.

Inferior rate performance, insufficient cycle life, and low mass loading have restricted the practical application of hard carbon (HC) anodes in sodium-ion batteries (NIBs). Here, a compatible strategy is developed by matching HC anodes with an ether-based electrolyte. Systematical investigation reveals that good compatibility of the electrode-electrolyte systems forms thinner but a more sustainable solid-electrolyte interphase and delivers a higher ionic conductivity and Na ion diffusion coefficient than the commonly used ester-based electrolytes.

Red Phosphorus Nanoparticle@3D Interconnected Carbon Nanosheet Framework Composite for Potassium-Ion Battery Anodes.

Red phosphorus (P) has been recognized as a promising storage material for Li and Na. However, it has not been reported for K storage and the reaction mechanism remains unknown. Herein, a novel nanocomposite anode material is designed and synthesized by anchoring red P nanoparticles on a 3D carbon nanosheet framework for K-ion batteries (KIBs).