An anode-free battery (AFB) is one that is manufactured without an anode. Instead, it creates a metal anode the first time it is charged. The anode is formed from charge carriers supplied by the cathode. As such, before charging, the battery consists of a cathode, current collectors, separator and electrolyte.
Conventional batteries use an anode made of graphite. However, the graphite consumes space, adds weight, adds to materials costs, and increases manufacturing complexity. As of 2023, the most practical designs that support lithium metal batteries are anode-free.
Anode-free batteries typically require a solid-state electrolyte made of a ceramic or polymer. This is to ensure that over many charge/discharge cycles, dendrites that may form on the anode-side current collector do not cross the electrolyte and short circuit the battery. Some solid-state designs use conventional graphite anodes.
The charge carriers electroplate lithium onto the anode current collector surface, there offering a solid electrolyte interphase (SEI). After the initial charge, an AFB operates as a lithium metal battery. [1] By eliminating the permanent lithium metal anode, AFBs operate with all the lithium acts as a charge carrier, rather than remaining at the anode (zero excess lithium). Manufacturing a lithium anode is also complex, as this involves making and manipulating a thin lithium foil, given its high reactivity and viscosity. However, some lithium is lost in each charge/discharge cycle, reducing cycle counts. Deposited lithium also tends to be of uneven depth and is more likely to produce dendrites. solid electrolyte interphase [2]
Anode-free lithium ion batteries have been demonstrated using a variety of cathode materials, such as LiFePO4, LiCoO2, and LiNi1/3Mn1/3Co1/3 (NMC111).
These intercalation-type cathodes typically offer limited Li content (14.3 at.% for LiFePO4, 25 at.% for LiCoO2 and LiNixCoyMn1-x-yO2), although they remain the primary research targets. [2] Oxide cathodes may release reactive oxygen radicals that trigger side reactions with flammable organic electrolytes. By contrast, lithium sulfide can reach 67% lithium. When fully lithiated, the cathode experiences negligible volume changes during cycling. [3] However, Li2S cathodes may suffer initial activation overpotential (~1.0 V) and poor charge kinetics. [3]
QuantumScape has developed one such battery. The company claimed an energy density of 325-440 Wh/kg (900-1,100 Wh/l) for its solid-state battery. As of 2020 the battery could sustain 800 cycles before dropping to 80% of its original capacity. [1] [4] Production is scheduled for the back half of 2024. [5]
One New Energy has demonstrated a battery pack that claims to offer 1,000 Wh/L. Each prismatic cell offers 240 Ah. To address limitations of power output, cycle life, and safety levels, the company adopted a dual-chemistry battery architecture, in which LFP cells are the primary power source, while its anode-free battery cells (LiMnO cathode) would be used to used to handle longer trips. This was expected to reduce cycles and peak power requirements by 90%. [6]
Samsung reported a high-nickel layered oxide cathode in a prototype pouch cell that offered >900 Wh/l, with stable Coulombic efficiency (>99.8%) over 1,000 cycles. [1]
Researchers at Pacific Northwest National Laboratory (PNNL) developed an anode-free device that uses a salt/salt electrolyte mixture dissolved in a solvent, solvent mixture, and/or polymer. The salt can be of various types of lithium salts. [7]
ION Storage Systems demonstrated a solid-state battery that lasted 125 cycles with less than 5% capacity loss. They use a 3-D ceramic structure in place of the anode. The battery is the first to satisfy the Advanced Research Projects Agency–Energy/Department of Energy room temperature charging goals. [8]
Anode-free batteries must address low-capacity oxygen-releasing intercalation cathodes and flammable liquid electrolytes. One alternative adopted a quasi-solid-state, non-flammable, polymeric gel electrolyte with lithium sulfide cathodes. The research claimed energy density of 1323 Wh L−1 at the pouch cell level. The design avoids uncontrolled exothermic reactive oxygen reactions and excess Li. The electrolyte employs MXene-doped fluorinated polymer that avoids polysulfide shuttling, and reduces dendrites. Cell safety against mechanical, electrical and thermal abuses was improved. [3]
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit. Electrodes are essential parts of batteries that can consist of a variety of materials depending on the type of battery.
A lithium-ion or Li-ion battery is a type of rechargeable battery that uses the reversible intercalation of Li+ ions into electronically conducting solids to store energy. In comparison with other commercial rechargeable batteries, Li-ion batteries are characterized by higher specific energy, higher energy density, higher energy efficiency, a longer cycle life, and a longer calendar life. Also noteworthy is a dramatic improvement in lithium-ion battery properties after their market introduction in 1991: over the following 30 years, their volumetric energy density increased threefold while their cost dropped tenfold.
A nanowire battery uses nanowires to increase the surface area of one or both of its electrodes, which improves the capacity of the battery. Some designs, variations of the lithium-ion battery have been announced, although none are commercially available. All of the concepts replace the traditional graphite anode and could improve battery performance. Each type of nanowire battery has specific advantages and disadvantages, but a challenge common to all of them is their fragility.
Rechargeable lithium metal batteries are secondary lithium metal batteries. They have metallic lithium as a negative electrode. The high specific capacity of lithium metal, very low redox potential and low density make it the ideal negative material for high energy density battery technologies. Rechargeable lithium metal batteries can have a long run time due to the high charge density of lithium. Several companies and many academic research groups are currently researching and developing rechargeable lithium metal batteries as they are considered a leading pathway for development beyond lithium-ion batteries. Some rechargeable lithium metal batteries employ a liquid electrolyte and some employ a solid-state electrolyte.
The lithium–sulfur battery is a type of rechargeable battery. It is notable for its high specific energy. The low atomic weight of lithium and moderate atomic weight of sulfur means that Li–S batteries are relatively light. They were used on the longest and highest-altitude unmanned solar-powered aeroplane flight by Zephyr 6 in August 2008.
The thin-film lithium-ion battery is a form of solid-state battery. Its development is motivated by the prospect of combining the advantages of solid-state batteries with the advantages of thin-film manufacturing processes.
A solid-state battery is an electrical battery that uses a solid electrolyte for ionic conductions between the electrodes, instead of the liquid or gel polymer electrolytes found in conventional batteries. Solid-state batteries theoretically offer much higher energy density than the typical lithium-ion or lithium polymer batteries.
The lithium–air battery (Li–air) is a metal–air electrochemical cell or battery chemistry that uses oxidation of lithium at the anode and reduction of oxygen at the cathode to induce a current flow.
A potassium-ion battery or K-ion battery is a type of battery and analogue to lithium-ion batteries, using potassium ions for charge transfer instead of lithium ions. It was invented by the Iranian/American chemist Ali Eftekhari in 2004.
Sodium-ion batteries (NIBs, SIBs, or Na-ion batteries) are several types of rechargeable batteries, which use sodium ions (Na+) as their charge carriers. In some cases, its working principle and cell construction are similar to those of lithium-ion battery (LIB) types, but it replaces lithium with sodium as the intercalating ion. Sodium belongs to the same group in the periodic table as lithium and thus has similar chemical properties. However, in some cases, such as aqueous batteries, SIBs can be quite different from LIBs.
Sir Peter George Bruce, is a British chemist, and Wolfson Professor of Materials in the Department of Materials at the University of Oxford. Between 2018 and 2023, he served as Physical Secretary and Vice President of the Royal Society. Bruce is a founder and Chief Scientist of the Faraday Institution.
Aluminium-ion batteries are a class of rechargeable battery in which aluminium ions serve as charge carriers. Aluminium can exchange three electrons per ion. This means that insertion of one Al3+ is equivalent to three Li+ ions. Thus, since the ionic radii of Al3+ (0.54 Å) and Li+ (0.76 Å) are similar, significantly higher numbers of electrons and Al3+ ions can be accepted by cathodes with little damage. Al has 50 times (23.5 megawatt-hours m-3) the energy density of Li and is even higher than coal.
Research in lithium-ion batteries has produced many proposed refinements of lithium-ion batteries. Areas of research interest have focused on improving energy density, safety, rate capability, cycle durability, flexibility, and reducing cost.
Magnesium batteries are batteries that utilize magnesium cations as charge carriers and possibly in the anode in electrochemical cells. Both non-rechargeable primary cell and rechargeable secondary cell chemistries have been investigated. Magnesium primary cell batteries have been commercialised and have found use as reserve and general use batteries.
A zinc-ion battery or Zn-ion battery (abbreviated as ZIB) uses zinc ions (Zn2+) as the charge carriers. Specifically, ZIBs utilize Zn as the anode, Zn-intercalating materials as the cathode, and a Zn-containing electrolyte. Generally, the term zinc-ion battery is reserved for rechargeable (secondary) batteries, which are sometimes also referred to as rechargeable zinc metal batteries (RZMB). Thus, ZIBs are different than non-rechargeable (primary) batteries which use zinc, such as alkaline or zinc–carbon batteries.
The glass battery is a type of solid-state battery. It uses a glass electrolyte and lithium or sodium metal electrodes.
Calcium (ion) batteries are energy storage and delivery technologies (i.e., electro–chemical energy storage) that employ calcium ions (cations), Ca2+, as the active charge carrier. Calcium (ion) batteries remain an active area of research, with studies and work persisting in the discovery and development of electrodes and electrolytes that enable stable, long-term battery operation. Calcium batteries are rapidly emerging as a recognized alternative to Li-ion technology due to their similar performance, significantly greater abundance, and lower cost.
A solid-state silicon battery or silicon-anode all-solid-state battery is a type of rechargeable lithium-ion battery consisting of a solid electrolyte, solid cathode, and silicon-based solid anode.
This is a history of the lithium-ion battery.
Superconcentrated electrolytes, also known as water-in-salt or solvent-in-salt liquids, usually refer to chemical systems, which are liquid near room temperature and consist of a solvent-to-dissoved salt in a molar ratio near or smaller than ca. 4-8, i.e. where all solvent molecules are coordinated to cations, and no free solvent molecules remain. Since ca. 2010 such liquid electrolytes found several applications, primarily for batteries. In the case of lithium metal batteries and lithium-ion batteries most commonly used anions for superconcentrated electrolytes are those, that are large, asymmetric and rotationally-vibrationally flexible, such as bis(trifluoromethanesulfonyl)amide and bis(fluorosulfonyl)amide. Noteworthy, lithium chloride and sodium perchlorate also form water-in-salt solutions.