Search

DE-102015217747-B4 - Active material for a positive electrode of a battery cell, positive electrode and battery cell

DE102015217747B4DE 102015217747 B4DE102015217747 B4DE 102015217747B4DE-102015217747-B4

Abstract

Positive active material (A) (42) for a positive electrode (22) of a battery cell (2), comprising a first component (A1) which includes a compound of general formula (III): Li 2-z Na z MnO 3-y N y (III) where 3 > y >0; and 2 > z > 0.

Inventors

  • Thomas ECKL
  • Anika Marusczyk

Assignees

  • ROBERT BOSCH GMBH

Dates

Publication Date
20260513
Application Date
20150916

Claims (10)

  1. Positive active material (A) (42) for a positive electrode (22) of a battery cell (2), comprising a first component (A1) which includes a compound of general formula (III): Li 2-z Na z MnO 3-y N y (III) where 3 > y >0; and 2 > z > 0.
  2. Positive active material (A) (42) according to Claim 1 , characterized in that 1.5 ≥ y > 0, in particular 0.5 ≥ y > 0.
  3. Positive active material (A) (42) according to Claim 1 or 2 , characterized in that 1 ≥ z ≥ 0.1.
  4. Positive active material (A) (42) according to one of the Claims 1 until 3 , characterized in that the positive active material (A) (42) comprises a second component (A2) which contains LiMO 2 , wherein M is a transition metal selected from the elements nickel, cobalt and/or manganese.
  5. Positive active material (A) (42) according to Claim 4 , characterized in that the positive active material (A) (42) comprises a compound of formula (IV): x(LiMO 2 ):1-x(Li 2-z Na z MnO 3-y N y ) (IV) where 1 > x ≥ 0; 3 > y >0; and 2 > z > 0.
  6. Positive electrode (22) of a battery cell (2) comprising a positive active material (A) (42) according to one of the preceding claims.
  7. Positive electrode (22) after Claim 6 , characterized in that a coating (52) containing aluminium fluoride (AlF 3 ) is applied to the positive active material (A) (42).
  8. Positive electrode (22) after Claim 6 or 7 , characterized in that a coating (52) containing carbon is applied to the positive active material (A) (42).
  9. Battery cell (2) comprising at least one positive electrode (22) according to one of the Claims 6 until 8 .
  10. Use of a battery cell (2) according Claim 9 in an electric vehicle (EV), in a hybrid vehicle (HEV), in a plug-in hybrid vehicle (PHEV), in a tool or in a consumer electronics product.

Description

The invention relates to an active material (A) for a positive electrode of a battery cell, comprising a first component ( A1 ) containing Li₂MnO₃ doped with nitrogen ions. The invention also relates to a positive electrode of a battery cell comprising an active material (A) according to the invention, and to a battery cell comprising at least one positive electrode according to the invention. State of the art The storage of electrical energy has become increasingly important in recent decades. Electrical energy can be stored using batteries. Batteries convert chemical reaction energy into electrical energy. A distinction is made between primary and secondary batteries. Primary batteries are only functional once, while secondary batteries, also known as accumulators, are rechargeable. A battery comprises one or more battery cells. Lithium-ion battery cells are primarily used in accumulators. These are characterized, among other things, by high energy density, thermal stability, and extremely low self-discharge. Lithium-ion battery cells have a positive electrode and a negative electrode. Each positive and negative electrode includes a current collector onto which a positive or negative active material is applied, respectively. The positive and negative active material is characterized in particular by its ability to reversibly store and release lithium ions. The active material for the negative electrode is, for example, amorphous silicon, which can form intercalation compounds with lithium atoms. Carbon compounds, such as graphite, are also commonly used as active materials for negative electrodes. Lithium atoms are embedded within the active material of the negative electrode. The active material for the positive electrode is typically a lithium-containing metal oxide or a lithium-containing metal phosphate. Particularly in applications requiring high energy density, so-called high-energy materials such as HE (high-energy)-NCM (nickel-cobalt-manganese) electrodes (e.g., LiMO₂ : Li₂MnO₃ with M = Ni, Co, Mn) are used. A battery of this type that uses such an HE-NCM electrode is, for example , made of... DE 10 2012 208 321 A1 known. During operation of the battery cell, i.e., during a discharge process, electrons flow in an external circuit from the negative electrode to the positive electrode. Inside the battery cell, lithium ions migrate from the negative electrode to the positive electrode during discharge. In this process, the lithium ions are reversibly deposited from the active material of the negative electrode, a process also known as lithiation. During a charging process, the lithium ions migrate from the positive electrode to the negative electrode. In this process, the lithium ions are reversibly deposited back into the active material of the negative electrode, a process also known as lithiation. The electrodes of the battery cell are foil-like and wound into an electrode coil with a separator in between, which separates the negative electrode from the positive electrode. Such an electrode coil is also called a jelly roll. The electrodes can also be stacked on top of each other. The two electrodes of the electrode winding or electrode stack are electrically connected to the terminals of the battery cell via commutators. A battery cell typically comprises one or more electrode windings or electrode stacks. The electrodes and the separator are surrounded by an electrolyte, usually a liquid. This electrolyte is conductive for lithium ions, enabling their transport between the electrodes. EP 2 728 660 A deals with positive active materials for high-energy lithium-ion batteries based on HE-NCM materials. US 2014/0099559 A1 Disclosed is an electrode for a battery comprising an active material selected from LiCoO₂ , LiMn₂O₄ , Li₂MnO₃ , LiNiO₂ , LiMn₁₅Ni₀₅O₄ , LiFePO₄ , Li₂FePO₄F , Li₃CONiMnO₆ , Li( Li₃Ni₅Mn₅Co₂ ) O₂ , and mixtures thereof. The material may further be doped with other metals. In addition , a coating of the electrode with a nitrogen - containing carbon composition is disclosed. Conventional HE-NCMs are characterized by the fact that they deliver high cell voltages at the beginning of the cell's life, which are subject to significant losses over time (so-called voltage fade). The same applies to the cell's capacity (so-called capacity fade). Task The purpose of this invention is therefore to provide an active material for a positive electrode which maintains a high cell voltage and capacity even after a long cell lifetime. From the publication of Kong, F.; Longo, R.C.; Park, M.-S.; Yoon, J.; Yeon, O.-H.; Park, J,-H:; Wang, W.-H.; “Ab initio study of doping effects on LiMnO2 and Li2MnO3 cathode materials for Li-ion batteries,” Journal of Materials Chemistry A, Vol. 3, 2015, pp. 8489-8500 The investigation of the influence of 10 cationic (Mg, Ti, V, Nb, Fe, Ru, Co, Ni, Cu and Al) and 2 anionic dopants (N and F) on the phase stability, redox potential and ionic and electronic conductivity of