The advantages and disadvantages of lithium manganate batteries

The advantages of lithium manganese are good rate performance, simple manufacture and low cost. Its disadvantage is that the dissolution of manganese will lead to poor high-temperature performance and cycle performance. By doping aluminum and sintering granulation, high-temperature performance and cycle performance are better, and basically satisfy practical usage. In general, lithium manganese battery has low cost, good stability, strong low-temperature performance, but poor high-temperature performance and shorter cycle life.

The positive materials of low cost, safety, and low temperature performance is good, but the material itself is not so stable, easy to decompose to produce gas, so much for mixed with other materials used, in order to reduce the cost of batteries, but the attenuation of cycle life quickly, prone to bulge, high temperature performance is poorer, relatively short life, it is mainly used for large and medium-sized batteries, Power battery the nominal voltage of 3.7 V.

There are three kinds of manganese acid lithium: 1 layered manganese acid lithium LiMnO2, theoretical capacity of 285 ma · h/g, 4 v voltage platform. Layered structure synthesis, are stable and easy to generate Li2Mn2O4 spinel structure and led to the decrease of the voltage platform, poor stability, the irreversible capacity attenuation, etc.

2 high pressure LiMn2O4 spinel manganic acid lithium, theoretical capacity of 148 ma · h/g, 4.15 voltage platform. High temperature performance is poor, 55 ℃ above capacity attenuation. Easy into Li2Mn2O4 spinel structure while also led to the decrease of the voltage platform, poor stability, the irreversible capacity attenuation, etc. Industrial manganese acid lithium is used on this.

3 spinel lithium manganese acid Li2Mn2O4, low voltage (v) 3, low capacity, poor circulation, are studying how to avoid this kind of thing.

Ternary: in order to solve the defects of layered manganese acid lithium, by the method of metal elements doping, invented the Ni, Co (Al) instead of manganese ternary material LiNiCoMnO2 (LiNiCoAlO2), both the high voltage, high capacity of nickel acid lithium manganese acid lithium high-pressure high security, good circulation of cobalt acid lithium, and overcome the lithium manganese acid lithium nickel acid synthesis difficult and unstable, the shortcomings of high cost of cobalt acid lithium, become the mainstream of the current positive electrode material. The theoretical capacity is 280 ma · h/g, voltage 2.7 ~ 4.2, now the actual capacity of around 160 ma · h/g.

Three yuan in the next few years, the basic will be eliminated after three years, high nickel and NCA for leading role. Estimate the whole three yuan will be eliminated 10 years later, there will be new the battery system to replace the three yuan.

Mainly for spinel manganese acid lithium manganese acid lithium LiMn2O4 spinel manganese acid lithium is Hunter in 1981, first of all, the system has 3 d the anode material of lithium ion channels, so far has been great attention by many scholars and researchers both at home and abroad, it as electrode materials with low price and high potential, environment friendly, safety performance is high, is the most hope to become a new generation of replacing cobalt acid lithium LiCoO2Lithium ion batteries the anode material.

Manganese acid lithium is a promising one of lithium ion battery anode materials, compared with the traditional anode materials, such as cobalt acid lithium manganese acid lithium is rich in resources, low cost, no pollution, good safety, ratio performance is good wait for an advantage, is the ideal power battery cathode material, but its poor circulation and electrochemical stability performance is greatly limits its industrialization. Mainly includes spinel manganese acid lithium manganese acid lithium manganese acid lithium and layered structure, including spinel lithium manganese acid stable structure, easy to realize industrialized production, products are now market for this kind of structure. Spinel lithium manganese acid belongs to the cubic crystal system, Fd3m space group, the theory of specific capacity is 148 mah/g, with 3 d tunnel structure, lithium ion can be reversibly from spinel lattice nested, will not cause the collapse of structures, thus has excellent performance and stability.

Now, the traditional thought manganese acid lithium the disadvantage of low energy density, low cycle performance and has had the very big change, can force a new typical values: 123 mah/g, 400 times, high circular typical values 107 mah/g, 2000).Surface modification and doping can effectively modified its electrochemical properties, surface modification can effectively inhibit the dissolution of manganese and electrolyte decomposition. Doping can effectively inhibit Jahn - Teller effect in the process of charging and discharging. Combines surface modification and doping are sure to further improve the electrochemical performance of the material, believe that will be the future of spinel lithium manganese acid modified one of the research direction.

LiMn2O4 is a kind of typical ion crystal, and there are positive, the two configurations. XRD analysis normal spinel LiMn2O4 is Fd3m symmetry cubic crystal, crystal lattice constant a = 0.8245 nm, crystal cell volume V = 0.5609 nm3.Oxygen ions of face-centered cubic close packing (ABCABC...., adjacent oxygen octahedrons take associated edges), lithium 1/8 oxygen tetrahedral gap (V4) position (Li0.5 Mn2O4 orderly arrangement structure of lithium, lithium in order to occupy 1/16 oxygen tetrahedral gap), manganese occupy oxygen 1/2 octahedral gap (V8) position.56 atomic unit cell contains: eight lithium atoms, 16 mn atom, 32 oxygen atoms, the Mn3 + and Mn4 + 50% each. Because of the spinel structure of the cell length is general face-centered cubic (FCC) structure model of two times, therefore, each cell actually consists of 8 cubic unit. The eight cubic unit can be divided into a, b two types. Every two coplanar cubic unit belong to different types of structure, every two cubic unit belong to the similar structure of the edges. Each small cubic unit has four oxygen ions, which are located in the body of the diagonal point to the center of the vertex of diagonal 1/4 and 3/4 point. Its structure can be simply described as eight tetrahedral 8 a position by lithium ion, 16 octahedral position (16 d) occupied by manganese ions, 16 d position of manganese is Mn3 + and Mn4 + according to the proportion of 1:1, octahedral all 16 c position vacancy, oxygen ions octahedral 32 e position. This structure in the MnO6 oxygen octahedrons take associated edges, forming a continuous three-dimensional cubic arrangement, namely (M2) m1 spinel structure network for lithium ion diffusion provides a tetrahedral lattice 8 a, 48 f and octahedral crystal lattice 16 c coplanar formation of the three-dimensional empty word. When lithium ion diffusion in the structure, according to a sequential path on the 8th of 16 c - a - linear diffusion (tetrahedron 8 a location can run under oxygen octahedrons 16 16 c or d position can base), an Angle of 107 ° diffusion path, which is used as a secondary lithium ion battery cathode material of theoretical basis.

The production of lithium manganese acid

Spinel lithium manganese acid synthesis method has a lot of kinds, mainly include high temperature solid phase method, melt impregnation method, microwave synthesis method, sol-gel method, emulsion drying method, coprecipitation method, Pechini method and hydrothermal synthesis method.

Now on the market the main lithium manganese acid has the AB two classes, class A refers to the power battery material, its characteristic is mainly considering security and circularity. Substitute for class B refers to the mobile phone battery. Its characteristics are mainly high capacity.

Production mainly by the EMD of manganese acid lithium and lithium carbonate as raw material, cooperate with the corresponding additives, after mixing, firing, post processing steps such as the production. As for the characteristics of raw materials and production technology, production is non-toxic and environmentally friendly. Does not produce waste gas, wastewater can be recycled in the production of powder. Therefore has no impact on the environment.

Now main indicator of A kind of material is: the reversible capacity between 100 ~ 115, circularity can reach more than 500 times remain 80% of capacity.(1 c);Class B material capacity is higher, general requirements at around $120, but for the cyclical low relative requirements, ranging from 300 ~ 500, the capacity retention rate can reach more than 60%.Of course, the price of class A and class B, there is still A gap on the price.

Manganese acid lithium battery is correct use of manganese acid lithium batteries, lithium manganese acid battery its nominal voltage from 2.5 v to 4.2 v, manganese acid lithium battery with low cost, good safety and widely used.

The output voltage range: 2.5 ~ 4.2 v nominal capacity: 7500 mAh

Standard continuous discharge current: 0.2 C

Maximum continuous discharge current: 1 c

Working temperature: charging: 0 ~ 45 ℃

Discharge: - 20 ~ 60 ℃

Lead models: the marking UL3302/26 #, 50 mm white line for 10 k NTC

Protection plate parameters: (each parameter can be set up according to the customer the product)

The overcharge protection voltage/each string of 4.28 + / - 0.025 V

Discharge voltage protection 2.4 + / - 0.1 V

Flow value: 2 ~ 4 a

The positive materials of low cost, nice security, and low temperature performance is good, but the material itself is not so stable. It is easy to decompose and produce gas, so it tends to be used with other materials, in order to reduce the cost of batteries. But it has shorter cycle life, poorer high-temperature performance, and is prone to bulge. It is mainly used for large and medium-sized batteries and power battery. It nominal voltage is 3.7 V.

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